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1
Shen, Y., R. Lindenbergh, B. Hofland e R. Kramer. "CHANGE ANALYSIS OF LASER SCANS OF LABORATORY ROCK SLOPES SUBJECT TO WAVE ATTACK TESTING". ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W4 (13 de setembro de 2017): 139–47. http://dx.doi.org/10.5194/isprs-annals-iv-2-w4-139-2017.
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For better understanding how coastal structures with gentle slopes behave during high energy events, a wave attack experiment representing a storm of 3000 waves was performed in a flume facility. Two setups with different steepness of slope were compared under the same conditions. In order to quantify changes in the rock slopes after the wave attack, a terrestrial laser scanner was used to obtain 3D coordinates of the rock surface before and after each experiment. Next, through a series of processing steps, the point clouds were converted to a suitable 2D raster for change analysis. This allowed to estimate detailed and quantitative change information. The results indicate that the area around the artificial coast line, defined as the intersection between sloped surface and wave surface, is most strongly affected by wave attacks. As the distances from the sloped surface to the waves are shorter, changes for the mildly sloped surface, slope 1 (1 : 10), are distributed over a larger area compared to the changes for the more steeply sloped surface, slope 2 (1 : 5). The results of this experiment show that terrestrial laser scanning is an effective and feasible method for change analysis of rock slopes in a laboratory setting. Most striking results from a process point of view is that the transport direction of the rocks change between the two different slopes: from seaward transport for the steeper slope to landward transport for the milder slope.
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Kwon, Young-Hoo, Lonn Hutcheson, Jeffrey B. Casebolt, Joong-Hyun Ryu e Kunal Singhal. "The Effects of Railroad Ballast Surface and Slope on Rearfoot Motion in Walking". Journal of Applied Biomechanics 28, n.º 4 (agosto de 2012): 457–65. http://dx.doi.org/10.1123/jab.28.4.457.
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The purpose of this study was to investigate the effects of transversely sloped ballasted walking surface on gait and rearfoot motion (RFM) parameters. Motion analysis was performed with 20 healthy participants (15 male and 5 female) walking in six surface-slope conditions: two surfaces (solid and ballasted) by three slopes (0, 5, and 10 degrees). The gait parameters (walking velocity, step length, step rate, step width, stance time, and toe-out angle) showed significant surface effect (p= .004) and surface-slope interaction (p= .017). The RFM motion parameters (peak everted/inverted position, eversion/inversion velocity, and acceleration) revealed significant surface (p= .004) and slope (p= .024) effects. The ballasted conditions showed more cautious gait patterns with lower walk velocity, step length, and step rate and longer stance time. In the RFM parameters, the slope effect was more notable in the solid conditions due to the gait adaptations in the ballasted conditions. Ballast conditions showed reduced inversion and increased eversion and RFM range. The RFM data were comparable to other typical walking conditions but smaller than those from running.
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Zhu, Xiaoxiao, Sheng Nie, Cheng Wang, Xiaohuan Xi, Dong Li, Guoyuan Li, Pu Wang, Di Cao e Xuebo Yang. "Estimating Terrain Slope from ICESat-2 Data in Forest Environments". Remote Sensing 12, n.º 20 (11 de outubro de 2020): 3300. http://dx.doi.org/10.3390/rs12203300.
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The global digital elevation measurement (DEM) products such as SRTM DEM and GDEM have been widely used for terrain slope retrieval in forests. However, the slope estimation accuracy is generally limited due to the DEMs’ low vertical accuracy over complex forest environments. The Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) mission shows excellent potential for slope estimation because of the high elevation accuracy and unique design of beam pairs. This study aimed to explore the possibility of ICESat-2 data for terrain slope retrieval in the United States forests. First, raw ICESat-2 data were processed to obtain accurate ground surfaces. Second, two different methods based on beam pairs were proposed to derive terrain slopes from the ground surfaces. Third, the estimated slopes were validated by airborne LiDAR-derived slopes and compared with SRTM-derived slopes and GDEM-derived slopes. Finally, we further explored the influence of surface topography and ground elevation error on slope estimation from ICESat-2 data. The results show that the ground surface can be accurately extracted from all scenarios of ICESat-2 data, even weak beams in the daytime, which provides the basis for terrain slope retrieval from ICESat-2 beam pairs. The estimated slope has a strong correlation with airborne LiDAR-derived slopes regardless of slope estimation methods, which demonstrates that the ICESat-2 data are appropriate for terrain slope estimation in complex forest environments. Compared with the method based on along- and across-track analysis (method 1), the method based on plane fitting of beam pairs (method 2) has a high estimation accuracy of terrain slopes, which indicates that method 2 is more suitable for slope estimation because it takes full advantage of more ground surface information. Additionally, the results also indicate that ICESat-2 performs much better than SRTM DEMs and GDEMs in estimating terrain slopes. Both ground elevation error and surface topography have a significant impact on terrain slope retrieval from ICESat-2 data, and ground surface extraction should be improved to ensure the accuracy of terrain slope retrieval over extremely complex environments. This study demonstrates for the first time that ICESat-2 has a strong capability in terrain slope retrieval. Additionally, this paper also provides effective solutions to accurately estimate terrain slopes from ICESat-2 data. The ICESat-2 slopes have many potential applications, including the generation of global slope products, the improvement of terrain slopes derived from the existing global DEM products, and the correction of vegetation biophysical parameters retrieved from space-borne LiDAR waveform data.
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Xie, Huan, Hong Tang, Wenjia Du e Xiaohua Tong. "A Comparison of Surface Slopes Extracted from ICESat Waveform Data and High Resolution DEM". EPJ Web of Conferences 237 (2020): 01001. http://dx.doi.org/10.1051/epjconf/202023701001.
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Surface slope is an important topographic variable, accurate surface slope can support many research appliacations. Large footprint full waveform data has been used to estimate the surface slope and performes well. In this paper, surface slope within laser footprint is calculated using the Ice, Cloud, and land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) full waveform data and a high resolution Digital Elevation Model (REMA, the Reference Elevation Model of Antarctica). A comparison is done between two extracted surface slopes, the results show that the slopes extracted from full waveform data are close to slopes extracted from DEM, and the width of waveform can be used to extract surface slope in moderately sloping surface.
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Tang, Hua, Zhenjun Wu, Ailan Che, Conghua Yuan e Qin Deng. "Failure Mechanism of Rock Slopes under Different Seismic Excitation". Advances in Materials Science and Engineering 2021 (20 de fevereiro de 2021): 1–16. http://dx.doi.org/10.1155/2021/8866119.
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In earthquake-prone areas, special attention should be paid to the study of the seismic stability of rock slope. Particularly, it becomes much more complicated for the rock slopes with weak structural surfaces. In this study, numerical simulation and the shaking table test are carried out to analyze the influence of seismic excitation and structural surface in different directions on dynamic response of rock slope. Huaping slope with bedding structural surfaces and Lijiang slope with discontinuous structural surfaces besides Jinsha River in Yunnan Province are taken as research objects. The results of numerical simulation and the model test both show that discontinuous structure surface has influence on the propagation characteristics of seismic wavefield. For Huaping slope, the seismic wavefield responses repeatedly between the bedding structural surface and slope surface lead to the increase of the amplification effect. The maximum value of seismic acceleration appears on the empty surface where terrain changes. Horizontal motion plays a leading role in slope failure, and the amplification coefficient of horizontal seismic acceleration is about twice that of vertical seismic acceleration. The failure mode is integral sliding along the bedding structural surface. For Lijiang slope, seismic acceleration field affected by complex structural surface is superimposed repeatedly in local area. The maximum value of seismic acceleration appears in the local area near slope surface. And the dynamic response of slope is controlled by vertical and horizontal motion together. Under the seismic excitation with an intense of 0.336 g in X direction and Z direction, the amplification coefficients of seismic acceleration of Lijiang slope are 3.23 and 3.18, respectively. The vertical motion leads to the cracking of the weak structural surface. Then, Lijiang slope shows the toppling failure mode under the action of horizontal motion.
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Dixon, Philippe C., e David J. Pearsall. "Gait Dynamics on a Cross-Slope Walking Surface". Journal of Applied Biomechanics 26, n.º 1 (fevereiro de 2010): 17–25. http://dx.doi.org/10.1123/jab.26.1.17.
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The purpose of this study was to determine the effect of cross-slope on gait dynamics. Ten young adult males walked barefoot along an inclinable walkway. Ground reaction forces (GRFs), lower-limb joint kinematics, global pelvis orientation, functional leg-length, and joint reaction moments (JRMs) were measured. Statistical analyses revealed differences across limbs (up-slope [US] and down-slope [DS]) and inclinations (level; 0°; and cross-sloped, 6°). Adaptations included increases of nearly 300% in mediolateral GRFs (p< .001), functional shortening the US-limb and elongation of the DS-limb (p< .001), reduced step width (p= .024), asymmetrical changes in sagittal kinematics and JRM, and numerous pronounced coronal plane differences including increased US-hip adduction (and adductor moment) and decreased DS-hip adduction (and adductor moment). Data suggests that modest cross-slopes can induce substantial asymmetrical changes in gait dynamics and may represent a physical obstacle to populations with restricted mobility.
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Tang, Xiao Song, Ying Ren Zheng e Hui Ming Tang. "Numerical Analysis on the Evolutionary Features of Deformation and Failure Modes of Slope". Applied Mechanics and Materials 204-208 (outubro de 2012): 144–54. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.144.
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The failure of slope is a gradual accumulation process. Under the effect of many interior and exterior factors, some parts in the slope reach yield with the increase of stress; sliding surface forms gradually till complete transfixion; with the plastic strain continuous increases, overall failure happens on the slope. Traditional analysis method cannot display the mechanic conditions and the whole process of deformation, transfixion of sliding surfaces and failure. Meanwhile, FEM strength reduction can quantitatively show the deformation features and the process of occurrence and development of sliding surface. Based on the previous researches, the paper classifies slopes according to the features of rock and soil and the slope structure. Through analyzing the graphs of deformation and the nephograms of plastic strain under different reduction factors or safety factors, the researchers can directly find the deformation tendency of slopes and the whole process of the extension, transfixion and failure of sliding surface with the reduction of safety factor. So, the failure mechanism of slope can be found intuitively, which can provide effective basis for the prevention and governance of slopes.
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Li, Xun, Yujing Jiang e Satoshi Sugimoto. "Research on the Influence of Spatial Dimensions on the Stability of Large-Scale Slopes under Heavy Rainfall". GeoHazards 5, n.º 3 (18 de julho de 2024): 732–54. http://dx.doi.org/10.3390/geohazards5030037.
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In engineering practice, slope stability is commonly assessed using a two-dimensional (2D) analysis under the assumption of plane strain conditions. However, when dealing with the complex surface geometries of three-dimensional (3D) slopes, especially under short-term heavy rainfall conditions, relying solely on a 2D cross-sectional analysis may not always yield conservative results compared to 3D slope stability assessments. To investigate the applicability of using 2D cross-sections to represent 3D slopes, this study examines the influence of surface geometries on 3D slope stability. By varying the degree and frequency of surface undulations along a certain longitudinal length of the slope, as well as different variations in slope gradient, the impacts of these factors on the safety factor of 3D slopes under rainfall conditions are analyzed. The findings indicate that for 3D slopes with significant surface undulations and high-frequency variations, the safety factor is generally lower compared to that obtained from the 2D cross-sectional analysis. Furthermore, the variation in slope gradient has a more pronounced effect on the safety factor of 3D slopes compared to surface undulations, particularly when the slope gradients are larger than 50°. Therefore, the influence of spatial dimensions on the stability of slopes can be significant when dealing with complex surface geometries of 3D large-scale slopes. It is highly recommended to conduct both 3D and 2D analyses to ensure the accuracy of the slope stability analysis.
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Wen, Sen, Li Min Zhao e Yu Qing Yuan. "Study on Slope Surface Shape of Homogeneous Soil Slope". Applied Mechanics and Materials 170-173 (maio de 2012): 1158–61. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.1158.
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The research on slope is concentrated on stability analysis at present. Although there is little research on slope surface shape, it has important theoretical and practical significance. Based on guaranteeing the same earthwork, the shape of slope surfaces between single gradient slope surface and two-gradient slope surface whose lower part is steeper than upper part are compared. It’s concluded that (1) based on guaranteeing the same earthwork, two-gradient slope surface, whose lower part is steeper than upper part, is stabler than single gradient slope surface and when the lower part is vertical wall, the slope is stablest; (2) the height of vertical wall has a knee point, i.e. when more than this value ,the stability of slope decreases.
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MIYAZAKI, KATURA. "KNOTS THAT HAVE MORE THAN TWO ACCIDENTAL SLOPES". Journal of Knot Theory and Its Ramifications 13, n.º 06 (setembro de 2004): 749–61. http://dx.doi.org/10.1142/s0218216504003445.
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An accidental surface in the exterior of a knot in the 3-sphere is a closed essential surface for which there is an annulus in the knot exterior X connecting a loop in the surface and a nontrivial loop in ∂X, the peripheral torus of the knot. The isotopy class of the loop in ∂X is called an accidental slope; each accidental surface has a unique accidental slope. It is known that accidental slopes are integral or 1/0, and there is a knot with two accidental slopes 0 and 1/0. We show that for any integer m≥0, there is a hyperbolic knot which has m+1 accidental surfaces with accidental slopes 0,1,…,m.
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Yang, Yu-chuan, Hui-ge Xing, Xing-guo Yang e Jia-wen Zhou. "Determining the Critical Slip Surface of Three-Dimensional Soil Slopes from the Stress Fields Solved Using the Finite Element Method". Mathematical Problems in Engineering 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/7895615.
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The slope stability problem is an important issue for the safety of human beings and structures. The stability analysis of the three-dimensional (3D) slope is essential to prevent landslides, but the most important and difficult problem is how to determine the 3D critical slip surface with the minimum factor of safety in earth slopes. Basing on the slope stress field with the finite element method, a stability analysis method is proposed to determine the critical slip surface and the corresponding safety factor of 3D soil slopes. Spherical and ellipsoidal slip surfaces are considered through the analysis. The moment equilibrium is used to compute the safety factor combined with the Mohr-Coulomb criteria and the limit equilibrium principle. Some assumptions are introduced to reduce the search range of center points and the radius of spheres or ellipsoids. The proposed method is validated by a classical 3D benchmark soil slope. Simulated results indicate that the safety factor of the benchmark slope is 2.14 using the spherical slip surface and 2.19 using the ellipsoidal slip surface, which is close to the results of previous methods. The simulated results indicate that the proposed method can be used for the stability analysis of a 3D soil slope.
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Huang, Kang, Haipeng Duan, Yuelin Yi, Fei Yu, Shanxiong Chen e Zhangjun Dai. "Laboratory Model Tests on Flow Erosion Failure Mechanism of a Slope Consisting of Anqing Group Clay Gravel Layer". Geofluids 2021 (13 de março de 2021): 1–14. http://dx.doi.org/10.1155/2021/5559052.
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The Anqing group clay gravel layer is a special geological body composed of gravel and clay. In excavation projects, involving this soil, such a gravel layer, is prone to slope collapse and instability under the influence of rainfall. To clearly understand the failure mechanism and influencing factors of clay gravel slopes, an indoor artificial rainfall erosion model testing was carried out to analyse the effect of various slope ratios, gravel contents, and rainfall intensities. The slope erosion damage form, runoff rate, infiltration rate, scoured material, and slope stability of the clay gravel slope were studied. The test results show that sloping surfaces of the gentle slope were mainly damaged by erosion, and the degree of damage gradually increased from the top to the bottom of the sloping surface; however, the stability of the surface was good. In the case of the sloping surface layer of the steep slope, large-scale landslides occurred, and the stability of the surface was poor. When the gravel content was small, the surface failure was manifested as a gully failure. When the gravel content was large, it was manifested as a “layer-by-layer sliding” failure. The degree of influence of different conditions on the stable runoff rate was as follows: rainfall intensity>slope ratio>gravel content. The degree of influence of the parameters on the stable infiltration rate was as follows: slope ratio>rainfall intensity>gravel content. On gentle slopes, the total mass of the scoured material was inversely proportional to the gravel content and directly proportional to the rainfall intensity; on a steep slope, the total mass of the scoured material increased with an increase in the rainfall intensity and gravel content. Moreover, the slope ratio was the key influencing factor to decide whether there was gravel in the scoured material.
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Zhang, Q., J. Wang e F. Wu. "Spatial heterogeneity of surface roughness on tilled loess slopes in erosion stages". Soil and Water Research 13, No. 2 (13 de abril de 2018): 90–97. http://dx.doi.org/10.17221/130/2017-swr.
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The main soil erosion areas of the Chinese Loess Plateau are tilled slopes. The knowledge of their spatial heterogeneity will contribute to the understanding of erosion mechanisms on a microtopographic scale. In this study, the spatial heterogeneity of four conventionally tilled slopes was examined under simulated rainfall conditions using a semivariogram-based methodological framework. Results show that all tilled slopes have a relatively stable spatial structure and the erosion stages of all tilled slopes have a similar spatial variability. The rainfall in the splash, sheet, and rill erosion stages has a degree of relief effect, strengthening effect, and relief effect on the surface roughness, respectively. However, the effects of tillage practices and slope gradient on the spatial heterogeneity are much larger than those of the rainfall. The spatial heterogeneity decreases with increasing slope gradient. The general autocorrelation scale of the tilled slopes is 3.15 m and their fractal dimension ranges from 1.59 to 1.85. The tilled slopes have certain anisotropy with respect to the slope direction from 10° to 22.5° while they show isotropy or weaker anisotropy in other directions. In this work, a semivariogram-based methodological framework was established for the spatial heterogeneity of microtopographic-scale slopes. The results also provide a theoretical foundation for future tillage measures on sloping fields of the Loess Plateau.
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Zhang, Bin, Maosheng Zhang, Hao Liu, Pingping Sun, Li Feng, Tonglu Li e Yimin Wang. "Water Flow Characteristics Controlled by Slope Morphology under Different Rainfall Capacities and Its Implications for Slope Failure Patterns". Water 14, n.º 8 (14 de abril de 2022): 1271. http://dx.doi.org/10.3390/w14081271.
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The high sensitivity of loess slopes to water has been emphasized in many studies. However, it is still limited in terms of the understanding of slope morphological differentiation on the overall and local failure patterns in slopes, as well as on the acquisition method of hydrological dynamics. In this study, rainfall characteristics and slope surface morphological differences were introduced. Geoelectric and environmental factors were monitored. On this basis, apparent resistivity corrected by seasonal temperature and its relationship with soil water content was calibrated. The water migration characteristics and potential failure patterns of three slope morphologies were evaluated. The results are: (i) the improved resistivity method can better reflect the water flow movement within the slope, and it performs well after being corrected by temperature; (ii) the characteristics of surface runoff and water infiltration are directly affected by the cumulative rainfall value, and especially when the cumulative rainfall is >70 mm threshold, the surface runoff quickly infiltrates into the deep of the slope along the preferential paths; (iii) the interception ability of loess slope morphology to the surface runoff is concave slope > convex slope > linear slope; (iv) with the continuous rainfall, the convex surface of a slope is prone to be damaged by saturated mud flow. When the cumulative rainfall threshold is 70 mm, the preferential flow is easily excited on the concave surface of the slope, resulting in local collapse at the slope toe and mid-deep landslides.
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Harmon, John M., Morgan L. Cable, Scott J. Moreland e José E. Andrade. "Predicting the Effect of Surface Properties on Enceladus for Landing". Planetary Science Journal 4, n.º 8 (1 de agosto de 2023): 150. http://dx.doi.org/10.3847/psj/acec49.
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Abstract The prospect of landing on the surface of Enceladus comes with the question of whether the surface conditions permit selection and certification of one or more safe landing sites in an area of high science value. On Enceladus, the search for biosignatures in plume materials is a high science value objective that correlates with proximity to the south polar terrain, where the plume deposition rate is highest; however, such areas may be unsafe if unsintered particles make the landing site unstable. To investigate this, the surface of Enceladus was modeled using the level set discrete element method. This method models the kinetics and kinematics of large groups of individual ice particles both in contact and sintered together. Using the model, a rigid footpad was initialized at a 1 m s−1 descent just above the ice surface under Enceladus gravity. Parameters studied were the sintering amount, particle size distribution, footpad geometry, and surface slope. The model predicted that some sintering is required for the surface to support a lander; however, too much sintering can cause a lander to bounce. For tests on sloped surfaces, landing could be possible on slopes as steep as 20° for certain conditions, but it is safest to land in areas with a slope angle of 15° or less. While slope angle and sintering level were much more important than footpad geometry, the hemisphere footpad had the best performance (lowest slipping) in most cases compared to the cone or disk.
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Chalaturnyk, R. J., J. D. Scott, D. H. K. Chan e E. A. Richards. "Stresses and deformations in a reinforced soil slope". Canadian Geotechnical Journal 27, n.º 2 (1 de abril de 1990): 224–32. http://dx.doi.org/10.1139/t90-026.
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Nonlinear finite element analyses were performed on a nonreinforced embankment and a polymeric reinforced embankment, with 1:1 side slopes, constructed on competent foundations. The nonreinforced and reinforced embankment analyses are compared to examine the influence of polymeric reinforcement within a soil slope. It is shown that significant reductions in the shearing, horizontal, and vertical strains within the slope occur because of the presence of the reinforcement.The finite element analysis of the reinforced embankment construction gives the magnitude and distribution of load within the reinforcement. For all embankment heights, the maximum reinforcement load did not occur in the lowest reinforcing layer but in the reinforcing layer placed 0.4H above the foundation, where H is the height of the slope. The displacement patterns and surface deformations of the nonreinforced and reinforced slopes are compared to show the marked reduction in slope movements resulting from the presence of the reinforcement.The location and shape of potential shear surfaces within the homogeneous reinforced slope are examined. The position of the maximum load in each reinforcing layer within the reinforced slope indicates that, for the example studied, a circular-shaped slip surface represents a probable failure mechanism within the slope. Key words: soil reinforcement, geotextiles, finite element, slope stability, geogrids, limit equilibrium, reinforced slope.
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Zuievska, N., L. Shaidetska, T. Kosenko e Z. Hutsuliak. "Application of engineering measures for the stabilization of the soil slope". Collection of Research Papers of the National Mining University 73 (junho de 2023): 187–96. http://dx.doi.org/10.33271/crpnmu/73.187.
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Purpose. Analysis of the application of engineering measures to stabilize the soil slope with a building located near its edge using the Slide software package Methodology. To achieve this goal, calculations were made to determine the coefficient of slope stability when performing various engineering measures that would stabilize the slope and, if possible, save costs. In conditions of dense urban development, measures to stabilize the slope are chosen on the basis of not only taking into account geological conditions. It is necessary to analyze architectural solutions, landscape, the presence of neighboring structures, and so on. The method of round-the-cylindrical sliding surfaces is used, which is based on the calculation of possible sliding surfaces during displacements. The task of the calculation is to determine the stability coefficient of the slope for the most dangerous sliding surface. The results of the study. The calculated parameters of shear stability are determined: stability margin coefficient, coordinate of the sliding surface start, sliding depth, sliding surface end coordinate. To ensure the stability of the slope or slope, it is necessary that the stability margin coefficient is greater than 1, but it must be borne in mind that, depending on the class of responsibility of the structure, the required value of the stability reserve coefficient can be in the range of 1.25 – 1.80 and is regulated by the relevant type and class of construction standards (DBN). Scientific novelty. The possibility of predicting the behavior of natural slopes and artificial slopes in the process of their development and economic activity is obtained. Practical value. The used method of circular-cylindrical slip surfaces involves a large amount of monotonous calculations to determine the stability coefficient for each probable slip line and therefore the use of the software package will more effectively determine the parameters of slope stability, you can solve the issue of choosing the location of structures and designing measures to protect the territory from landslide processes on the slopes.
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Wu, Qing, Yuee Chen e Lu Zhang. "Experimental Study of Influence of Grass Coverage on Runoff Shear Force of the Slope Surface". Advanced Materials Research 430-432 (janeiro de 2012): 1791–94. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1791.
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Through outdoor artificial simulation test, the influence of the grass coverage on runoff shear force of the slope surface was studied. The results showed that the slope surface runoff shear force decreased with the increase of the grass coverage. In the experimental condition of 30° slope and 5L/min flow magnitude, runoff average shear force of the bare slope, low coverage and high coverage of the slope surface were respectively 0.9 Pa, 0.5 Pa and 0.3 Pa. The fluctuation changing range along the riser and the test diachronic of the slope surface runoff shear force of all kinds of slopes decreased with the increasing of the grass coverage.
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Repadi, J. A., F. Bari, F. A. Ismail, A. Andriani e A. Hakam. "A new slip surface in noncohesive slopes". IOP Conference Series: Materials Science and Engineering 1212, n.º 1 (1 de janeiro de 2022): 012033. http://dx.doi.org/10.1088/1757-899x/1212/1/012033.
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Abstract Determining the slope slip surface is difficult, prominent and uncertain. Slip-surface are utilized to estimate slope safety. This study aimed at investigating the slip surface caused by statistical loads by using experimental testing methods. The experimental method was conducted by providing a statistical load on the sand slope The load was used until the slope collapsed. Sand slopes were modeled in a glass box measuring 110 cm x 40 cm x 10 cm. The sand material used was sand that passed through sieve no.10 and was held by sieve no. 200. At a distance of 2.5 cm horizontally and at a distance of 5 cm vertically, colored marks were used to see the pattern of grain movement. Observations were conducted until the slope collapsed. The collapse pattern revealed in the experimental method is non-circular.
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Pingree, R. D., e B. Le Cann. "Structure, strength and seasonality of the slope currents in the Bay of Biscay region". Journal of the Marine Biological Association of the United Kingdom 70, n.º 4 (novembro de 1990): 857–85. http://dx.doi.org/10.1017/s0025315400059117.
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Slope currents in the Bay of Biscay show a consistent poleward transport but seasonal trends and vertical current structure appear more variable. Indeed more long term records are required to establish seasonal trends firmly.In the south of the region (Spanish slopes, mooring 118), the upper-slope (water depth 1005 m) flow exhibited a strong vertical structure with the maximum surface inflow occurring in the winter period, and this effect may be wind induced. Satellite imagery shows that this flow originates from the Iberian slope and that a decreasing along-slope surface transport occurs along the north Spanish slopes at this time of year.In the north of the region (Porcupine Seabight slopes) vertical structure was again evident in the upper slope (~1000–m depth) flow. At mooring 114 the flow at mid–depth showed a weakening along-slope flow and an on-slope tendency in the March/April period; a complete reversal in the slope current occurred at mid–depths at the position of mooring 112 during March.In the central region (Celtic and -Armorican slopes) seasonal variations in the upper layers on the slopes were also present. In this region, the upper–slope transport (2500m depth) reached maximum values of 3–5 Sv in late summer. Upper flows at the rise (mooring 8002) were directed on-slope during the period of maximum upper–slope transport but changed direction in the March/April period.In this region on the Celtic shelf (DB1), the surface flow is in a counter–current sense and wind-induced and so the seasonal variations here reflect seasonality in the wind stress.
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Yi, Donghui, H. Jay Zwally e Xiaoli Sun. "ICESat measurement of Greenland ice sheet surface slope and roughness". Annals of Glaciology 42 (2005): 83–89. http://dx.doi.org/10.3189/172756405781812691.
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AbstractThe Ice, Cloud and land Elevation Satellite (ICESat) in its 8 day repeat orbit mode provided data not only on the along-track surface slope, but also on the cross-track surface slope from adjacent repeat ground tracks. During the first 36 days of operation, four to five such repeat orbits occurred within 1 km in the cross-track direction. This provided an opportunity to use ICESat data to measure surface slope in the cross-track direction at 1 km scale. An algorithm was developed to calculate the cross-track surface slope. Combining the slopes in the cross-track and along-track directions gives a three-dimensional surface slope at 1 km scale. The along-track surface slope and surface roughness at 10km scale are also calculated. A comparison between ICESat surface elevation and a European Remote-sensing Satellite (ERS-1) 5 km digital elevation model shows a difference of 1–2 m in central Greenland where the surface slope is small, and >20m at the edge of Greenland where the surface slope is large. The large elevation difference at the edge is most likely due to the slope-induced error in radar altimeter measurement. Accurate surface slope data from ICESat will help to correct the slope-induced error of radar altimeter missions such as Geosat, ERS-1 and ERS-2.
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Zhao, Lianheng, Nan Qiao, Zhigang Zhao, Shi Zuo e Xiang Wang. "Comparative study of material point method and upper bound limit analysis in slope stability analysis". Transportation Safety and Environment 2, n.º 1 (abril de 2020): 44–57. http://dx.doi.org/10.1093/tse/tdaa002.
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Abstract The upper bound limit analysis (UBLA) is one of the key research directions in geotechnical engineering and is widely used in engineering practice. UBLA assumes that the slip surface with the minimum factor of safety (FSmin) is the critical slip surface, and then applies it to slope stability analysis. However, the hypothesis of UBLA has not been systematically verified, which may be due to the fact that the traditional numerical method is difficult to simulate the large deformation. In this study, in order to systematically verify the assumption of UBLA, material point method (MPM), which is suitable to simulate the large deformation of continuous media, is used to simulate the whole process of the slope failure, including the large-scale transportation and deposition of soil mass after slope failure. And a series of comparative studies are conducted on the stability of cohesive slopes using UBLA and MPM. The proposed study indicated that the slope angle, internal friction angle and cohesion have a remarkable effect on the slip surface of the cohesive slope. Also, for stable slopes, the calculation results of the two are relatively close. However, for unstable slopes, the slider volume determined by the UBLA is much smaller than the slider volume determined by the MPM. In other words, for unstable slopes, the critical slip surface of UBLA is very different from the slip surface when the slope failure occurs, and when the UBLA is applied to the stability analysis of unstable slope, it will lead to extremely unfavorable results.
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Palermo, Vincenzo. "Slope-controlled surface instabilities". Philosophical Magazine Letters 84, n.º 3 (março de 2004): 157–64. http://dx.doi.org/10.1080/09500830310001660080.
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Nearing, Mark A., Viktor O. Polyakov, Mary H. Nichols, Mariano Hernandez, Li Li, Ying Zhao e Gerardo Armendariz. "Slope–velocity equilibrium and evolution of surface roughness on a stony hillslope". Hydrology and Earth System Sciences 21, n.º 6 (30 de junho de 2017): 3221–29. http://dx.doi.org/10.5194/hess-21-3221-2017.
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Abstract. Slope–velocity equilibrium is hypothesized as a state that evolves naturally over time due to the interaction between overland flow and surface morphology, wherein steeper areas develop a relative increase in physical and hydraulic roughness such that flow velocity is a unique function of overland flow rate independent of slope gradient. This study tests this hypothesis under controlled conditions. Artificial rainfall was applied to 2 m by 6 m plots at 5, 12, and 20 % slope gradients. A series of simulations were made with two replications for each treatment with measurements of runoff rate, velocity, rock cover, and surface roughness. Velocities measured at the end of each experiment were a unique function of discharge rates, independent of slope gradient or rainfall intensity. Physical surface roughness was greater at steeper slopes. The data clearly showed that there was no unique hydraulic coefficient for a given slope, surface condition, or rainfall rate, with hydraulic roughness greater at steeper slopes and lower intensities. This study supports the hypothesis of slope–velocity equilibrium, implying that use of hydraulic equations, such as Chezy and Manning, in hillslope-scale runoff models is problematic because the coefficients vary with both slope and rainfall intensity.
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Higgin, Dwight, Alexander Krupka, Omid Haji Maghsoudi, Alexander N. Klishko, T. Richard Nichols, Mark A. Lyle, Boris I. Prilutsky e Michel A. Lemay. "Adaptation to slope in locomotor-trained spinal cats with intact and self-reinnervated lateral gastrocnemius and soleus muscles". Journal of Neurophysiology 123, n.º 1 (1 de janeiro de 2020): 70–89. http://dx.doi.org/10.1152/jn.00018.2019.
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Sensorimotor training providing motion-dependent somatosensory feedback to spinal locomotor networks restores treadmill weight-bearing stepping on flat surfaces in spinal cats. In this study, we examined if locomotor ability on flat surfaces transfers to sloped surfaces and the contribution of length-dependent sensory feedback from lateral gastrocnemius (LG) and soleus (Sol) to locomotor recovery after spinal transection and locomotor training. We compared kinematics and muscle activity at different slopes (±10° and ±25°) in spinalized cats ( n = 8) trained to walk on a flat treadmill. Half of those animals had their right hindlimb LG/Sol nerve cut and reattached before spinal transection and locomotor training, a procedure called muscle self-reinnervation that leads to elimination of autogenic monosynaptic length feedback in spinally intact animals. All spinal animals trained on a flat surface were able to walk on slopes with minimal differences in walking kinematics and muscle activity between animals with/without LG/Sol self-reinnervation. We found minimal changes in kinematics and muscle activity at lower slopes (±10°), indicating that walking patterns obtained on flat surfaces are robust enough to accommodate low slopes. Contrary to results in spinal intact animals, force responses to muscle stretch largely returned in both SELF-REINNERVATED muscles for the trained spinalized animals. Overall, our results indicate that the locomotor patterns acquired with training on a level surface transfer to walking on low slopes and that spinalization may allow the recovery of autogenic monosynaptic length feedback following muscle self-reinnervation. NEW & NOTEWORTHY Spinal locomotor networks locomotor trained on a flat surface can adapt the locomotor output to slope walking, up to ±25° of slope, even with total absence of supraspinal CONTROL. Autogenic length feedback (stretch reflex) shows signs of recovery in spinalized animals, contrary to results in spinally intact animals.
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Xie, Jiren, Taro Uchimura, Chao Huang, Zain Maqsood e Jingli Tian. "Experimental Study on the Relationship between the Velocity of Surface Movements and Tilting Rate in Pre-Failure Stage of Rainfall-Induced Landslides". Sensors 21, n.º 18 (7 de setembro de 2021): 5988. http://dx.doi.org/10.3390/s21185988.
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With the development of deformation measuring technology at slope surfaces, prediction methods for rainfall-induced landslides based on the surface movements and tilting of slopes in the pre-failure stage have been recognized as a promising technique for risk reduction of slope failure triggered by rainfall. However, the correlation and possible mechanism for these prediction methods were rarely discussed. In this study, the comparison between the prediction methods of slope failure based on the time history of surface displacements and tilting in the acceleration stage was carried out by conducting a series of laboratory tests and field tests under rainfall, in which the movements and tilting behaviors at the slope surface were measured. The results show that the predicted failure time of tested slopes obtained by different prediction methods is consistent, and the correlation between these landslide prediction methods were also detected. A proportional relationship between the velocity of surface displacements and tilting rate was observed, and a possible mechanism for the sliding behavior was discussed based on this linear relationship as well. In addition, an expression for the linear relationship between the rate of the surface tilting and displacement was also established in this study, and the results could have significance for the understanding of the sliding behavior in the failure process in rainfall-induced landslides.
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Wang, Na, Lei Wang, Liang Jin, Jiajun Wu, Min Pang, Dan Wei, Yan Li et al. "Rainfall Runoff and Nitrogen Loss Characteristics on the Miyun Reservoir Slope". Water 16, n.º 5 (6 de março de 2024): 786. http://dx.doi.org/10.3390/w16050786.
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Rainfall intensity and slope gradient are the main drivers of slope surface runoff and nitrogen loss. To explore the distribution of rainfall runoff and nitrogen loss on the Miyun Reservoir slopes, we used artificial indoor simulated rainfall experiments to determine the distribution characteristics and nitrogen migration paths of surface and subsurface runoff under different rainfall intensities and slope gradients. The initial runoff generation time of subsurface runoff lagged that of surface runoff, and the lag time under different rainfall intensity and slope conditions ranges from 3.97 to 12.62 min. Surface runoff rate increased with increasing rainfall intensity and slope gradient; compared with a rainfall intensity of 40 mm/h, at a slope of 15°, average surface runoff rate at 60 and 80 mm/h increased by 2.38 and 3.60 times, respectively. Meanwhile, the subsurface runoff rate trended upwards with increasing rainfall intensity, in the order 5 > 15 > 10°. It initially increased and then decreased with increasing slope gradient, in the order 5 > 10 > 15°. Total nitrogen (TN) loss concentration of surface runoff shows a decrease followed by a stabilization trend; the concentration of TN loss decreases with decreasing rainfall intensity, and the stabilization time becomes earlier and is most obvious in 5° slope conditions. TN loss concentration in subsurface runoff decreased with increasing rainfall intensity, i.e., 40 > 60 > 80 mm/h. The surface runoff rainfall coefficient was mainly affected by rainfall intensity, a correlation between αs and slope gradients S was not obvious, and the fitting effect was poor. The subsurface runoff rainfall coefficient was mainly affected by slope gradient, the R2 of all rainfall intensities was <0.60, and the fitting effect was poor. The main runoff loss pathway from the Miyun Reservoir slopes was surface runoff, which was more than 62.57%. At the same time, nitrogen loss was subsurface runoff, more than 51.14%. The proportion of surface runoff to total runoff increases with the increase of rainfall intensity and slope, with a minimum of 62.57%, and the proportion of nitrogen loss from subsurface runoff also decreases with increasing rainfall intensity but does not change with slope gradient. The order of different runoff modulus types was mixed runoff (surface and subsurface runoff occur simultaneously) > surface runoff > subsurface runoff. The surface and mixed runoff modulus increased significantly with increasing rain intensity under different rain intensities and slope gradients. Overall, rainfall intensity significantly affected slope surface runoff, and slope gradient significantly affected nitrogen loss.
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Liu, Chuanzheng, Gang Wang e Wei Han. "Effect of Slip Surface’s Continuity on Slope Dynamic Stability Based on Infinite Slope Model". Mathematics 7, n.º 1 (8 de janeiro de 2019): 58. http://dx.doi.org/10.3390/math7010058.
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The slip surface is an important control structure surface existing in the landslide. It not only directly affects the stability of the slope through the strength, but also affects the stress field by affecting the propagation of the stress wave. Many research results have been made on the influence of non-continuous stress wave propagation in rock and soil mass and the dynamic response to seismic slopes. However, the effect of the continuity of the slip surface on the slope dynamic stability needs further researches. Therefore, in this paper, the effect of slip surface on the slope’s instantaneous safety factor is analyzed by the theoretical method with the infinite slope model. Firstly, three types of slip surface model were established, to realize the change of sliding surface continuity in the infinite slope. Then, based on wave field analysis, the instantaneous safety factor was used to analyze the effect of continuity of slip surface. The results show that with the decreasing of slip surface continuity, the safety factor does not simply increase or decrease, and is related to slope features, incident wave and continuity of slip surface. The safety factor does not decrease monotonically with the increasing of slope angle and thickness of slope body. Moreover, the reflection of slope surface has a great influence on the instantaneous safety factor of the slope. Research results in this paper can provide some references to evaluate the stability of seismic slope, and have an initial understanding of the influence of structural surface continuity on seismic slope engineering.
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Telhan, Gaurav, Jason R. Franz, Jay Dicharry, Robert P. Wilder, Patrick O. Riley e D. Casey Kerrigan. "Lower Limb Joint Kinetics During Moderately Sloped Running". Journal of Athletic Training 45, n.º 1 (1 de janeiro de 2010): 16–21. http://dx.doi.org/10.4085/1062-6050-45.1.16.
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Abstract Context: Knowledge of the kinetic changes that occur during sloped running is important in understanding the adaptive gait-control mechanisms at work and can provide additional information about the poorly understood relationship between injury and changes in kinetic forces in the lower extremity. A study of these potential kinetic changes merits consideration, because training and return-to-activity programs are potentially modifiable factors for tissue stress and injury risk. Objective: To contribute further to the understanding of hill running by quantifying the 3-dimensional alterations in joint kinetics during moderately sloped decline, level, and incline running in a group of healthy runners. Design: Crossover study. Setting: Three-dimensional motion analysis laboratory. Patients or Other Participants: Nineteen healthy young runners/joggers (age = 25.3 ± 2.5 years). Intervention(s): Participants ran at 3.13 m/s on a treadmill under the following 3 different running-surface slope conditions: 4° decline, level, and 4° incline. Main Outcome Measure(s): Lower extremity joint moments and powers and the 3 components of the ground reaction force. Results: Moderate changes in running-surface slope had a minimal effect on ankle, knee, and hip joint kinetics when velocity was held constant. Only changes in knee power absorption (increased with decline-slope running) and hip power (increased generation on incline-slope running and increased absorption on decline-slope running in early stance) were noted. We observed an increase only in the impact peak of the vertical ground reaction force component during decline-slope running, whereas the nonvertical components displayed no differences. Conclusions: Running style modifications associated with running on moderate slopes did not manifest as changes in 3-dimensional joint moments or in the active peaks of the ground reaction force. Our data indicate that running on level and moderately inclined slopes appears to be a safe component of training regimens and return-to-run protocols after injury.
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Zhabko, A. V. "A variational method of slope stability assessment". Mining Industry Journal (Gornay Promishlennost), n.º 3S/2024 (10 de agosto de 2024): 6–13. http://dx.doi.org/10.30686/1609-9192-2024-3s-06-13.
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The article discusses the variational method of assessing slope stability, which is based on the limit equilibrium method, but in contrast to the engineering techniques of stability assessment allows a mathematical justification (the variational calculus) of a single most dangerous slip surface in the rock mass, including the torsion angles and distribution of the interslice forces in its various sections. The main ideas and provisions of the proposed theory or concept, i.e. the variational method of slope stability calculation, are: 1) definition of the shape and position of the slip surface in the rock mass should be justified by strict mathematical (variational) methods, rather than by selection of the slip surface of a specified shape, for example, a circular slip surface; 2) calculation or assessment of stability, and more specifically, calculation of the shear and cohesion forces at various sections of the slip surface, depending on the geometry of the slip surface and the slope, as well as mechanical characteristics of the rocks and contact surfaces, is carried out using different composite functions (summarized force). The author demonstrates in the article that when applying engineering methods for calculating the stability of slopes for various types of their stability loss, in contrast to the variational method, their limiting (design) parameters are sharply overestimated. The author believes this to be the root cause of many accidents associated with the failure of slope structures. Application of the variational method of slope stability assessment allowed to establish new forms of slope stability loss and explain the abnormally steep slope angles of shear sites observed in practice.
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Nian, T. K., R. Q. Huang, S. S. Wan e G. Q. Chen. "Three-dimensional strength-reduction finite element analysis of slopes: geometric effects". Canadian Geotechnical Journal 49, n.º 5 (maio de 2012): 574–88. http://dx.doi.org/10.1139/t2012-014.
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The vast majority of slopes, both natural and constructed, exhibit a complex geometric configuration and three-dimensional (3D) state, whereas slopes satisfying the assumption of plane strain (infinite length) are seldom encountered. Existing research mainly emphasizes the 3D dimensions and boundary effect in slope stability analysis; however, the effect of complex geometric ground configuration on 3D slope stability is rarely reported. In this paper, an elastoplastic finite-element method using strength-reduction techniques is used to analyze the stability of special 3D geometric slopes. A typical 3D slope underlain by a weak layer with groundwater is described to validate the numerical modeling, safety factor values, and critical slip surface for the 3D slope. Furthermore, a series of special 3D slopes with various geometric configurations are analyzed numerically, and the effects of turning corners, slope gradient, turning arcs, and convex- and concave-shaped surface geometry on the stability and failure characteristics of slopes under various boundary conditions are discussed in detail.
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Yuan, L., F. Li, S. Zhang, S. Xie, F. Xiao, T. Zhu e Y. Zhang. "ANTARCTIC ICE SHEET SLOPE AND ASPECT BASED ON ICESAT’S REPEAT ORBIT MEASUREMENT". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W7 (14 de setembro de 2017): 1579–83. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w7-1579-2017.
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Accurate information of ice sheet surface slope is essential for estimating elevation change by satellite altimetry measurement. A study is carried out to recover surface slope of Antarctic ice sheet from Ice, Cloud and land Elevation Satellite (ICESat) elevation measurements based on repeat orbits. ICESat provides repeat ground tracks within 200 meters in cross-track direction and 170 meters in along-track direction for most areas of Antarctic ice sheet. Both cross-track and along-track surface slopes could be obtained by adjacent repeat ground tracks. Combining those measurements yields a surface slope model with resolution of approximately 200 meters. An algorithm considering elevation change is developed to estimate the surface slope of Antarctic ice sheet. Three Antarctic Digital Elevation Models (DEMs) were used to calculate surface slopes. The surface slopes from DEMs are compared with estimates by using in situ GPS data in Dome A, the summit of Antarctic ice sheet. Our results reveal an average surface slope difference of 0.02 degree in Dome A. High resolution remote sensing images are also used in comparing the results derived from other DEMs and this paper. The comparison implies that our results have a slightly better coherence with GPS observation than results from DEMs, but our results provide more details and perform higher accuracy in coastal areas because of the higher resolution for ICESat measurements. Ice divides are estimated based on the aspect, and are weakly consistent with ice divides from other method in coastal regions.
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Ketcheson, Scott J., e Jonathan S. Price. "Comparison of the hydrological role of two reclaimed slopes of different ages in the Athabasca oil sands region, Alberta, Canada". Canadian Geotechnical Journal 53, n.º 9 (setembro de 2016): 1533–46. http://dx.doi.org/10.1139/cgj-2015-0391.
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Establishing hydrological connectivity in reconstructed landscapes, and understanding how this connectivity evolves over time, is critical for the development of effective water management strategies after oil sands extraction. In the current study, the dominant controls on the soil water regimes and runoff generation mechanisms on two contrasting reclaimed slopes (2 and 6 years after reclamation) in the Athabasca oil sands region are investigated. The most recently reclaimed slope demonstrated a hydrologic regime with limited soil water storage due to a low surface infiltration capacity that constrained percolation of rainfall. Accordingly, this slope generated a substantial amount of surface runoff controlled primarily by precipitation intensity. Conversely, the older slope had a greater surface infiltration capacity, more dynamic soil water regime, and infrequent surface runoff. Topography controlled soil water distribution on the older slope more strongly than the newer slope due to more efficient water redistribution. This suggests that changes in the hydrophysical properties of reclamation materials following construction result in a shift in the hydrological role of reclaimed slopes at the watershed scale. Thus, over time, reclaimed slopes produce less overland flow and shift from water conveyors to water storage features in constructed watershed systems.
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Wang, Feichao, Guoce Xu, Lin Li, Zhanbin Li, Peng Li, Jianwen Zhang e Yuting Cheng. "Response Relationship between Microtopographic Variation and Slope Erosion under Sand-Cover". Water 11, n.º 12 (26 de novembro de 2019): 2488. http://dx.doi.org/10.3390/w11122488.
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Slope microtopography is an important factor that affects the process of slope erosion. We quantified the responses between microtopography and the amount of erosion on overland sand slope and loess slopes through an indoor artificial simulated rainfall experiment. Three continuous rainfall tests under 1.5 mm/min rain intensity were used to analyze the spatial variation of slope microtopography and soil erosion with three-dimensional laser scanning technology. Our results show that under 0.5, 1.0, and 1.5 cm sand-covered slopes, the runoff time of the first rainfall is delayed by 18, 19, and 23 min, respectively, compared with the loess slope. Furthermore, the average sediment concentration on the slope decreased with subsequent rainfall events. The total erosion of the slope under 0.5, 1.0, and 1.5 cm sand was 4.24, 3.57, and 5.40 times that of the loess slope, respectively. The erosion of the sand-covered slopes was much larger than that of the loess slope. The length of the main sand production area was about 2.4 times that of the loess slope and the peaks of the erosion amount of the slope were mostly distributed in the lower part of the slope. As the rainfall progressed, the microtopographic factors of the loess slopes increased significantly (p < 0.05), and the microtopographic factors of the sand slopes increased, but not significantly (p > 0.05). We found that the microtopographic factors with the strongest erosion responses to the loess slope and the sand-covered slope were surface incision and surface roughness. The response relationship between microtopographic variation and erosion of the loess slope was stronger than the sand-covered slope, and suggests that other, unaccounted-for factors may be affecting the erosion of sand-covered slopes. This study provides a reference for erosion mechanisms of the wind–water erosion crisscross region.
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Sasahara, Katsuo, Nobutaka Hiraoka, Naotaka Kikkawa e Kazuya Itoh. "Development of the surface displacement velocity in a full-scale loamy model slope under multistep excavation". Bulletin of Engineering Geology and the Environment 80, n.º 6 (24 de abril de 2021): 4389–403. http://dx.doi.org/10.1007/s10064-021-02226-1.
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AbstractMultistep excavations were implemented at the toe of a large-scale slope model, and the surface displacements in the slope were measured to examine the validity of the relationship between the velocity and acceleration proposed by Fukuzono for excavated slopes. The surface displacement increased both during and after slope excavation, among which the latter was due to creep deformation under a constant stress. The rate of increase in the surface displacement was initially high and then decreased to zero during creep deformation after the excavation without slope failure. However, the surface displacement exhibited an accelerated increase during creep deformation after the final excavation prior to slope failure; the surface displacement increased with small fluctuations even before slope failure occurred. The surface displacement velocity and acceleration also fluctuated notably due to variations in the surface displacement. The trendlines for the derived relationships between the velocity and acceleration were in good general agreement with the measured data at certain locations in the model slope. These relationships were unique at different locations on the slope, while the inclination of the relationship trendline suddenly decreased just prior to slope failure. The steeper trendlines predicted an earlier failure time if the displacement was large and close to the failure condition, whereas they resulted in worse predictions if the displacement was small and far from causing slope failure according to the prediction method proposed by Fukuzono.
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Machuga, Oleg, Mykola Borys e Yurii Lusta. "Methods of the terrain allowable slope determining for safe operation of specialized equipment under the non-stationary load action". Mechanics and Advanced Technologies 6, n.º 2 (1 de outubro de 2022): 130–38. http://dx.doi.org/10.20535/2521-1943.2022.6.2.257604.
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The operation of modern high-tech equipment requires a clear delineation of safe conditions for its operation. To a large extent, this applies to machines that move and work on untreated soil surface: forestry machinery, agricultural machinery, road construction machinery, military equipment, and so on. Asymmetry of the location of the working bodies, work on surfaces with a lateral slope, non-stationary interaction with the working environment - these are the factors that increase operational risks. Objective of this study is to establish the limits of safe operation of specialized machines operating on a rough surface with a slope to the horizon. The methods of determining safe slopes for the above-described equipment in the conditions of its non-stationary interaction with the subject of work are considered in the work. In particular, dangerous slopes that can cause the car to overturn or roll sideways are identified. The realization of this goal is achieved by building a mathematical model and appropriate calculation schemes that cover both possibilities of loss of stability. Graphs are plotted to display the maximum slopes due to the overturning and sliding of the machine on the slope for the specified operating loads. The integral characteristic of the slope limit value covers both of the above risks. The application of the proposed methods is illustrated by the calculation of the safe slope for firing tanks for different angles of deviation of the gun from the surface of the movement on the slope and the type of ground surface of the movement. The following results were obtained: methods for calculating the allowable slopes for the possibility of operating specialized machines on them, taking into account soil conditions, and demonstrated the application of the approach to the case of military equipment. The use of these results is a necessary factor for the implementation in the design of technological processes for specialized machines in order to minimize operational risks.
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Hazelton, Andrew T., Robert Rogers e Robert E. Hart. "Shear-Relative Asymmetries in Tropical Cyclone Eyewall Slope". Monthly Weather Review 143, n.º 3 (27 de fevereiro de 2015): 883–903. http://dx.doi.org/10.1175/mwr-d-14-00122.1.
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Abstract Recent studies have analyzed the azimuthal mean slope of the tropical cyclone (TC) eyewall. This study looks at the shear-relative azimuthal variability of different metrics of eyewall slope: the 20-dBZ surface, the radius of maximum wind (RMW), and an angular momentum (M) surface passing through the RMW. The data used are Doppler radar composites from the NOAA Hurricane Research Division (HRD). This study examines 34 TCs, with intensities ranging from 3 to 75 m s−1 and shear magnitudes ranging from 0 to 10 m s−1. Calculation of the mean slope in each quadrant for all cases shows that RMW slope has the strongest asymmetry, with downshear slope larger than upshear in 62% of cases. Slopes of momentum surfaces and dBZ surfaces are also greater downshear in some cases (65% for M and 47% for dBZ), but there is more variance than in the RMW slope. The azimuthal phase of maximum slope occurs most often downshear, particularly downshear left, consistent with the depiction of a mean vortex tilt approximately 10° left of shear. Filtering the cases into high and low shear illustrates that the tendency for greater slope downshear is magnified for high-shear cases. In addition, although the dBZ slope shows less shear-relative signal overall, the difference between the dBZ slope and momentum slope is an important factor in distinguishing between strengthening and weakening or steady TCs. Intensifying TCs tend to have dBZ surfaces that are more upright than M surfaces. Further investigation of these results will help to illustrate the ways in which vertical shear can play a role in altering the structure of the TC core region.
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Fan, Junwei, Shijiao Yang, Bo Deng, Bing Sun e Taoying Liu. "A New Technique of Lattice Beam Construction with Pre-Anchoring for Strengthening Cut Slope: A Numerical Analysis of Temporary Stability during Excavation". Buildings 12, n.º 11 (9 de novembro de 2022): 1930. http://dx.doi.org/10.3390/buildings12111930.
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In consideration of the temporary stability of the cutting slope during construction and its permanent stability under long-term service, a new technique of lattice beam construction with anchors pre-set in the slope from the original ground surface before cutting was proposed, and its construction process was briefly introduced. Compared with the model without pre-set anchors, the effectiveness of pre-setting anchors to strengthen the cutting slope during multi-excavation was verified in the numerical software FLAC3D. Various factors such as the factor of safety (FOS) and the maximum shear strain increment (MSSI) as well as the displacement for different stages were discussed. The results show that the anchors pre-set in the slope provide reinforcement step-by-step with excavations which changes the mechanical responses of the cutting slope and increases the factor of safety with a variation of 15.9–44.1% compared to the case without setting anchors. In addition, with excavations, the axial forces of the anchors pre-set in the stratum increase gradually, and the positions of the maximum axial forces gradually transfer from the vicinity of the cutting surface to the depth of the design slope. Numerical simulations prove that this new technique is beneficial for ensuring the temporary stability of the slope during excavations and is especially suitable for the advance anchorage of the cutting slope, in which the inclined original ground surface is cut at an angle steeper than it can stand safely and is close to the design slope surface after cutting. After the completion of slope excavation, the cast-in-place concrete lattice beam is immediately set on the design slope surface and connected with the anchor heads exposed on the cut slope surface to ensure the permanent stability of the slope. Therefore, this new technology has important guiding significance for both the temporary stability of slopes during construction and the permanent stability of slopes in service.
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Picard, Ghislain, Marie Dumont, Maxim Lamare, François Tuzet, Fanny Larue, Roberta Pirazzini e Laurent Arnaud. "Spectral albedo measurements over snow-covered slopes: theory and slope effect corrections". Cryosphere 14, n.º 5 (7 de maio de 2020): 1497–517. http://dx.doi.org/10.5194/tc-14-1497-2020.
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Abstract. Surface albedo is an essential variable to determine the Earth's surface energy budget, in particular for snow-covered areas where it is involved in one of the most powerful positive feedback loops of the climate system. In situ measurements of broadband and spectral albedo are therefore common. However they are subject to several artefacts. Here we investigate the sensitivity of spectral albedo measurements to surface slope, and we propose simple correction algorithms to retrieve the intrinsic albedo of a slope from measurements, as if it were flat. For this, we first derive the analytical equations relating albedo measured on a slope to intrinsic direct and diffuse albedo, the apportionment between diffuse and direct incoming radiation, and slope inclination and aspect. The theory accounts for two main slope effects. First, the slope affects the proportion of solar radiation intercepted by the surface relative to that intercepted by the upward-looking, horizontal, sensor. Second, the upward- and downward-looking sensors receive reduced radiation from the sky and the surface respectively and increased radiation from neighbouring terrain. Using this theory, we show that (i) slope has a significant effect on albedo (over 0.01) from as little as a ≈1∘ inclination, causing distortions of the albedo spectral shape; (ii) the first-order slope effect is sufficient to fully explain measured albedo up to ≈15∘, which we designate “small-slope approximation”; and (iii) for larger slopes, the theory depends on the neighbouring slope geometry and land cover, leading to much more complex equations. Next, we derive four correction methods from the small-slope approximation, to be used depending on whether (1) the slope inclination and orientation are known or not, (2) the snow surface is free of impurities or dirty, and (3) a single or a time series of albedo measurements is available. The methods applied to observations taken in the Alps on terrain with up to nearly 20∘ slopes prove the ability to recover intrinsic albedo with a typical accuracy of 0.03 or better. From this study, we derive two main recommendations for future field campaigns: first, sloping terrain requires more attention because it reduces the measurement accuracy of albedo even for almost invisible slopes (1–2∘). Second, while the correction of the slope effect is possible, it requires additional information such as the spectral diffuse and direction partitioning and if possible the actual slope inclination and aspect, especially when the absence of impurities can not be assumed.
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Michalowski, Radoslaw L. "Expanding collapse in partially submerged granular soil slopes". Canadian Geotechnical Journal 46, n.º 12 (dezembro de 2009): 1371–78. http://dx.doi.org/10.1139/t09-064.
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The traditional approach to stability analysis of granular slopes leads to the safety factor that is associated with a planar failure surface approaching the slope face, whether the slope is “dry” or submerged. However, for partially submerged slopes, a more critical, nonplanar failure surface can be formed. A family of geometrically similar surfaces can be found that is characterized by the same safety factor. If the safety factor drops down to unity and the slope becomes unstable, then a mechanism of any size can form. Alternatively, the failure may start at some small region and then the volume of the mechanism of failure can expand, giving rise to a progressive failure of a different kind that is typically associated with slopes. This progression has the character of a “disturbance” or a shock-like kinematic discontinuity propagating into the soil at rest. A quantitative analysis is presented and it is demonstrated that the soil dilates while the mechanism expands, leaving the slope weakened and susceptible to a deep failure. This is a plausible mode of failure of partially submerged slopes, the type that is most likely responsible for large subaqueous landslides, and is similar to the well-documented instability propagation in “quick clay.”
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Haupt, S., B. Sibolla e L. W. Mdakane. "TIME SERIES INSAR ANALYSIS FOR SLOPE STABILITY MONITORING USING SENTINEL-1 IN OPEN PIT MINING". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-1/W2-2023 (13 de dezembro de 2023): 945–51. http://dx.doi.org/10.5194/isprs-archives-xlviii-1-w2-2023-945-2023.
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Abstract. Surface mining is an important economic activity in many regions where mineral resources are located close to the surface. The process of ore extraction is characterised by high pit walls with steep slopes. The mining process introduces significant stress and strain changes that could lead to movement on the slope face. Slope failure on the pit walls can occur without warning and can lead to loss of life and disruptions to the mining process. The monitoring of slopes remains the most reliable way to detect movement on unstable slopes. Therefore, slope monitoring programmes have been established to monitor and measure slope movement to help mine management with the stability status of open pit slopes. Conventional monitoring techniques include visual inspections and in situ instrumentation that are point-based, time-consuming, and costly. Open-source remote sensing techniques such as Synthetic Aperture Radar interferometry have been used to monitor slope movements on open-pit mine walls. Time series interferometric Synthetic Aperture Radar (InSAR) can be used to overcome limitations of in-situ monitoring for monitoring slope movements in open-pit mines.
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Wang, Shuhong, Chengjin Zhu, Pengyu Wang e Zishan Zhang. "Stability Analysis of Slope with Multiple Sliding Surfaces Based on Dynamic Strength-Reduction DDA Method". Advances in Civil Engineering 2019 (11 de novembro de 2019): 1–12. http://dx.doi.org/10.1155/2019/2183732.
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The present study aims to elucidate the problem of a rock mass structural plane with a range of damage degrees and the numerical model selection for analysis of a slope with multiple sliding surfaces. Based on the relative displacement between blocks, the dynamic strength reduction-discontinuous deformation analysis (hereinafter referred to as DSR-DDA) method is proposed for studying slopes with multiple sliding surfaces. The slope-slider classic case was used to test the displacement threshold. The model was applied to the stability analysis of multiple sliding surfaces of a high rock slope in the Fushun West Open-Pit Mine. The results show that when the displacement threshold is set to 1 mm, the error between the DSR-DDA results and the theoretical solution is within 0.5%, which satisfies the calculation requirements. The most dangerous slip surface in the Fushun West Open-Pit Mine slope was identified. Based on the numerical slope model after the first landslide, the position of the secondary slip surface was then identified. The failure mode is traction sliding failure, and the middle and lower oil shales play a key role in the slope stability. This study recommends that mining of the remaining oil shale should stop to avoid causing large-scale landslides in the upper part of the slope and landslides at the pit-city boundary.
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Wang, Y., e B. Wu. "IMPROVED LARGE-SCALE SLOPE ANALYSIS ON MARS BASED ON CORRELATION OF SLOPES DERIVED WITH DIFFERENT BASELINES". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W1 (25 de julho de 2017): 155–61. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w1-155-2017.
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The surface slopes of planetary bodies are important factors for exploration missions, such as landing site selection and rover manoeuvre. Generally, high-resolution digital elevation models (DEMs) such as those generated from the HiRISE images on Mars are preferred to generate detailed slopes with a better fidelity of terrain features. Unfortunately, high-resolution datasets normally only cover small area and are not always available. While lower resolution datasets, such as MOLA, provide global coverage of the Martian surface. Slopes generated from the low-resolution DEM will be based on a large baseline and be smoothed from the real situation. In order to carry out slope analysis at large scale on Martian surface based low-resolution data such as MOLA data, while alleviating the smoothness problem of slopes due to its low resolution, this paper presents an amplifying function of slopes derived from low-resolution DEMs based on the relationships between DEM resolutions and slopes. First, slope maps are derived from the HiRISE DEM (meter-level resolution DEM generated from HiRISE images) and a series of down-sampled HiRISE DEMs. The latter are used to simulate low-resolution DEMs. Then the high-resolution slope map is down- sampled to the same resolution with the slope map from the lower-resolution DEMs. Thus, a comparison can be conducted pixel-wise. For each pixel on the slope map derived from the lower-resolution DEM, it can reach the same value with the down-sampled HiRISE slope by multiplying an amplifying factor. Seven sets of HiRISE images with representative terrain types are used for correlation analysis. It shows that the relationship between the amplifying factors and the original MOLA slopes can be described by the exponential function. Verifications using other datasets show that after applying the proposed amplifying function, the updated slope maps give better representations of slopes on Martian surface compared with the original slopes.
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Zhang, J., L. M. Zhang e Wilson H. Tang. "New methods for system reliability analysis of soil slopes". Canadian Geotechnical Journal 48, n.º 7 (julho de 2011): 1138–48. http://dx.doi.org/10.1139/t11-009.
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A slope may have many possible slip surfaces. As sliding along any slip surface can cause slope failure, the system failure probability of a slope is different from the probability of failure along an individual slip surface. In this paper, we first suggest an efficient method for evaluating the system failure probability of a slope that considers a large number of possible slip surfaces. To obtain more insights into the system failure probability of a slope, we also propose a method to identify a few representative slip surfaces most important for system reliability analysis among a large number of potential slip surfaces and to calculate the system failure probability based on these representative slip surfaces. An equation for estimating the bounds of system failure probability based on the failure probability of the most critical slip surface is also suggested. The system failure probability is governed by only a few representative slip surfaces. For a homogenous slope, the failure probability of the most critical slip surface is a good approximation of the system failure probability. For a slope in layered soils, the system failure probability can be significantly larger than the failure probability of the most critical slip surface.
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Rumbyarso, Yonas Prima Arga, e Gali Pribadi. "Analisis Stabilitas Lereng dengan Metode Bishop pada Proyek Geotechnical Investigation Jalur Transportasi Pelabuhan Batubara Marangkayu Kabupaten Kutai Kartanegara". JURNAL KRIDATAMA SAINS DAN TEKNOLOGI 5, n.º 02 (28 de dezembro de 2023): 562–77. http://dx.doi.org/10.53863/kst.v5i02.987.
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A slope is a surface that has a slope and forms a certain angle to the horizontal plane and is not protected. The slope and angle formed cause the slopes to have differences in surface height. Differences in slope surface height result in forces acting to push, and also forces in the soil acting to resist or resist, so that the position of the soil remains stable. The stability of a slope is expressed in the slope safety factor which is obtained or obtained by comparing the holding force and the pushing force. Based on topographic data of ground investigation drilling points on the Marangkayu Coal Port transportation route, Kutai Kartanegara Regency, it is known that there are several drilling points with soil conditions in the form of slopes or hills, so it is predicted that they could cause the potential for landslides because these points will become transportation routes for loading and unloading materials. coal. The aim of this research is to determine the slope safety figures, and to obtain a safe slope with the original slope conditions. The method used to analyze slope stability in this research uses Geostudio Slope Bishop method software. The results of the analysis of the original slope conditions at the OLC-FBH-03 and OLC-FBH-06 test points showed that the slope safety value was obtained with the result being that the slope condition was safe from landslides (FK>1.25). With this, it can be concluded that the Marangkayu Coal Harbor transportation route, Kutai Kartanegara Regency is safe from landslides.Keywords: Bishop Method, Geostudio Slope, Slope Stability, Slope Safety Value
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Zhi, Song, e Liu Yang. "Dynamic Response Differences Between Bedding and Counter-Tilt Rock Slopes with Intercalated Weak Layers". Journal of Disaster Research 11, n.º 4 (1 de agosto de 2016): 681–90. http://dx.doi.org/10.20965/jdr.2016.p0681.
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Bedding and counter-tilt rock slope with intercalated weak layers are common geological bodies in west China, the dynamic response research will guide the anti-seismic reinforcement of bedding and counter-tilt rock slope with intercalated weak layer effectively. Two test models of bedding rock slope with intercalated weak layer and counter-tilt rock slope with intercalated weak layer, which are in the same size, have been designed and developed. A large scale shaking table test has been performed to analyze the dynamic response difference of bedding and counter-tilt rock slope with intercalated weak layer. The study results show that the acceleration amplification coefficient inside the bedding slope is smaller than that inside the counter-tilt rock slope; at the middle and upper parts of the slope body (relative height > 0.4), the acceleration amplification coefficient at bedding rock slope surface is larger than that of counter-tilt rock slope. At the lower part of the slope (relative height le 0.4), the acceleration amplification coefficient at bedding rock slope surface is close to that of counter-tilt rock slope. The slope surface displacement of both bedding and counter-tilt rock slopes increases with increasing input seismic wave amplitude. The slope surface displacement of the bedding rock is larger than that of counter-tilt rock slope. The seismic stability of counter-tilt rock slope is stronger than bedding rock slope. The dynamic failure form of bedding rock slope mainly includes vertical tension crack at back edge, bedding sliding along intercalated weak layer and rock collapse at slope crest; whereas the dynamic failure form of counter-tilt slope mainly includes intersection of horizontal and vertical cracks on slope surface, extrusion of intercalated weak layer and shattering of slope crest.
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Lee, Kyutae, Ali R. Firoozfar e Marian Muste. "Technical Note: Monitoring of unsteady open channel flows using the continuous slope-area method". Hydrology and Earth System Sciences 21, n.º 3 (30 de março de 2017): 1863–74. http://dx.doi.org/10.5194/hess-21-1863-2017.
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Abstract. The advent of low-cost pressure transducers capable of directly measuring water surface elevation enables continuous measurements of dynamic water surface slopes. This opens up a new possibility of dynamically monitoring unsteady flows (i.e., hysteresis) during the course of flood wave propagation. Hysteresis in this context refers to a looped stage–discharge rating caused by unsteadiness of flows. Hysteresis is monitored in this study using a continuous slope area (CSA) method, which uses Manning's equation to calculate unsteady discharges based on continuously measured water surface slopes. In the rising stage, water surface slopes become steeper than a steady water surface slope, resulting in higher discharges than steady-based discharges, while the trends are reversed in the falling stage. The CSA method applied to Clear Creek near Oxford (Iowa, USA) estimates the maximum differences of peak discharges by 30–40 %, while it shows sound agreements for a low to medium range of discharges against USGS steady-based records. The primary cause of these differences is the use of a single channel bed slope in deriving Manning's roughness coefficients. The use of a single channel bed slope (conceptually equal to the water surface slopes at every stage in uniform flow conditions) causes substantial errors in estimating the channel roughness, specifically at high stages, because non-uniformities of natural channels result in varying (non-uniform) steady water surface slopes at each stage. While the CSA method is promising for dynamically tracking unsteady water surface slopes and flows in natural streams, more studies are still needed to increase the accuracy of the CSA method in future research.
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Li, Wei, Jie Cao e Rui Hua Zheng. "Centrifuge Modeling of Vertical Bearing Behavior of Bolt-Shotcrete Supported Slope". Advanced Materials Research 446-449 (janeiro de 2012): 1468–71. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1468.
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This paper presented the results of centrifuge model tests conducted to investigate the behavior of cohesive soil slopes under the vertical surface load, considering the bolt-shotcrete supported slopes. The cement layer and bolts influenced the behavior of the slope when surface vertical load was applied. The analysis of bearing capacity and displacement threw light on the failure and displacement distribution of the slope.
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Winkler, Antoniony S., Jaqueline T. da Silva, José M. B. Parfitt, Claudia F. A. Teixeira-Gandra, Germani Conceço e Luis C. Timm. "Surface drainage in leveled land: Implication of slope". Revista Brasileira de Engenharia Agrícola e Ambiental 22, n.º 2 (fevereiro de 2018): 77–82. http://dx.doi.org/10.1590/1807-1929/agriambi.v22n2p77-82.
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ABSTRACT In the lowlands of Rio Grande do Sul, land leveling is mostly carried out with no slope for the purpose of rice production. In this environment, soils with a low hydraulic conductivity are predominant owing to the presence of a practically impermeable B-horizon near the surface. Land leveling leads to soil accommodation resulting in the formation of depressions where water accumulates after heavy rainfalls, subsequently leading to problems with crops implanted in succession to rice, such as soybeans. The objective of this research was to quantify the areas and volumes of water accumulation in soil as a function of the slope of land leveling. Five typical leveled lowland areas were studied as a part of this research. The original areas presented slopes of 0, 0.20, 0.25, 0.28 and 0.40%, which were used to generate new digital elevation models with slopes between 0 and 0.5%. These newly generated digital models were used to map the depressions with surface water storage. In conclusion, land leveling with slopes higher than 0.1% is recommended to minimize problems with superficial water storage in rice fields.
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Varakian, Matthew, Nancy Chanover, Joseph Masiero e Dagmara Oszkiewicz. "3 μm Phase Curves of Main-belt Asteroids from NEOWISE Photometry". Planetary Science Journal 5, n.º 1 (1 de janeiro de 2024): 14. http://dx.doi.org/10.3847/psj/ad0c4d.
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Abstract The shapes of asteroid phase curves are influenced by the physical properties of asteroid surfaces. The variation of an asteroid’s brightness as a function of the solar phase angle can tell us about surface properties such as grain size distribution, roughness, porosity, and composition. Phase curves are traditionally derived from photometric observations at visible wavelengths, but phase curves using infrared data can also provide useful information about an asteroid surface. Using photometric observations centered near ∼3.4 μm from the W1 band of the Near-Earth Object Wide-field Infrared Survey Explorer mission, we construct thermally and rotationally corrected infrared phase curves for a sample of main-belt asteroids, which includes asteroids observed by the AKARI satellite, as well as subsets of the Themis and Flora dynamical families. We calculate the linear slope of the phase curves as a measure of their shape and compare W1 phase slopes to band depths of absorption features associated with hydrated materials, spectral slopes, visible albedos, W1 albedos, and diameters. We observe a steepening of the W1 phase slope of C-type asteroids with increasing 2.7 μm band depth but little correlation between the phase slope and 3 μm band depth or 3 μm spectral slope. The C-types in our sample exhibit steeper average W1 phase slopes than M- or S-types, similar to visible-light phase slopes. We also observe steeper W1 phase slopes for smaller-diameter objects within the Themis family and explore comparisons to Jupiter-family comets in phase slope versus albedo space.