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1
Zhang, Hong, Bang Zhang, Can Wu e Kun Chen. "Macro and micro analysis on coal-bearing soil slopes instability based on CFD-DEM coupling method". PLOS ONE 16, n. 9 (17 settembre 2021): e0257362. http://dx.doi.org/10.1371/journal.pone.0257362.
Testo completoAbstract (sommario):
By combining the discrete element method (DEM) with computational fluid dynamics (CFD), this study proposes a three-dimensional CFD–DEM fluid–solid coupling microscopic computational model for analyzing the micromechanisms of instability and failure in a coal-bearing soil slope during rainfall. The CFD–DEM fluid–solid coupling model indicated that the main failure mode of the coal-bearing soil slopes was rainwater washing, and the slope sliding surface was predicted as an approximately linear segment. The adaptability of this numerical method was verified by comparing its results with those of rain-washed slopes in an outdoor model test. Rainfall changed the microscopic parameters such as the force chain, coordination number, and porosity of the slope soil particles. The porosity of the slope’s top particles increased from 0.35 in the initial state to 0.80 in the unstable state. This change was directly related to the macroscopic mechanics of the slope soil. By analyzing the changes in the microscopic parameters of the particles, the failure evolution law of the coal-bearing soil slopes during rainfall was explored from a microscopic perspective. This study not only provides a theoretical basis for the protection design and construction of coal-bearing soil slopes in the region but can also analyze macroscopic mechanical laws of discrete media from a micro–macro perspective in geotechnical engineering.
2
Tan, Mengxi, e Sai K. Vanapalli. "Performance estimation of a shallow foundation on an unsaturated expansive soil slope subjected to rainfall infiltration". MATEC Web of Conferences 337 (2021): 03009. http://dx.doi.org/10.1051/matecconf/202133703009.
Testo completoAbstract (sommario):
In the last two decades, there has been a significant increase in infrastructure development on slopes of hilly regions of the world, due to population growth. There are many infrastructures on unsaturated expansive slopes, especially in semi-arid and arid regions. Rainfall infiltration is one of the major factors that contributes to the slope and infrastructure foundations failures on hilly slopes with unsaturated expansive soils. In the current study, a rational approach is proposed considering the combined influence of the foundation-slope behavior based on the principles of unsaturated soil mechanics. This is achieved by a novel numerical modelling approach using the commercial software Geo-studio to investigate the performance of strip foundation located on the top of the unsaturated expansive soil slope subjected to various rainfall infiltration conditions. Hydro-mechanical coupling analysis is conducted to evaluate the rainfall water infiltration influence combined with slope stability analysis using limit equilibrium method. Comparisons are made between both the foundation bearing capacity, slope stability before and after rainfall water infiltration. Different failure mechanisms of the foundation and slope system are presented with and without foundation loading for various rainfall scenarios. Results summarized in this paper are helpful for the geotechnical engineers for understanding the performance of shallow foundations on unsaturated expansive soil slopes considering the influence of rainfall infiltration conditions.
3
Chen, Bozhou, Wei Shui, Yuanmeng Liu e Ruyue Deng. "Analysis of Slope Stability with Different Vegetation Types under the Influence of Rainfall". Forests 14, n. 9 (13 settembre 2023): 1865. http://dx.doi.org/10.3390/f14091865.
Testo completoAbstract (sommario):
Rainfall-prone shallow landslides account for one-fifth of the global land area, and rainfall is critical to the mechanics and hydrology of shallow slopes. In typical geological disaster-prone areas, the hydrodynamic responses of slopes with different vegetation types under rainfall conditions require further study. The purpose of this study was to analyze the hydraulic stability of soils with different vegetation types under rainfall conditions and their effects on slope stability. Thus, the soil–water characteristic curves and water-stable aggregate characteristics of soils with three vegetation types were analyzed. A two-dimensional finite element model was used to simulate the slope stability of extreme rainfall environments with different rainfall durations. The results showed that the matric suction of soil with trees was less affected by rainfall with a better stability of water-stable aggregates than that of soil with shrubs and grass. The plastic strain cloud map showed that the maximum plastic strain occurred at the toe of the slope. In addition, the potential slip depth of slopes with trees was smaller than that of slopes with shrubs and grass. Under the two rainfall durations, the factor of safety (FoS) of slopes with trees changed by 0.06, whereas that of slopes with shrubs and grass changed by 0.1. The findings of this study provide valuable insights into changes in the stability of slopes with different vegetation types under varying rainfall conditions. It is of great significance to provide a scientific basis for the application of ecological measures in the prevention and control of mountain disasters and guide the implementation of appropriate land management measures.
4
Ma, Kuo-Chen, Yong-Jun Lin, Shyh-Yuan Maa e Yih-Chi Tan. "Evaluation of the effect of hysteretic flow and root system on shallow landslide". Soil Research 50, n. 7 (2012): 616. http://dx.doi.org/10.1071/sr12104.
Testo completoAbstract (sommario):
This paper analyses the mechanics of slope stability with regard to the hysteretic flow of unsaturated soil and the root system of the covering vegetation. The hysteresis of the soil water retention curves and root strength are important factors in the evaluation of unsaturated shear strength. Engineers should consider how the transportation of the soil water content and the plant root strength influence evaluation of surficial slope stability analysis. The integrated slope stability analysis considering the hysteretic flow and root strength were calculated on variations of the safety factor (SF) and in accordance with different infiltration profiles and several species of vegetation. The results show that it is possible to predict shallow landslide on unsaturated slopes covered by different vegetation types. Tree planting, in combination with mechanical reinforcement, on the slope’s toe was found to improve stability, in addition to having economic benefits. This process allows for the selection and comparison of combinations and densities of vegetation types, in order to find the optimum location for increased SF. This will quickly improve shallow slope stability before it is destroyed. A better understanding of the process mechanics, as provided by the model, is critical for a reliable and appropriate design for slope stabilisation.
5
Darban, Reza, Emilia Damiano, Aldo Minardo, Lucio Olivares, Luciano Picarelli e Luigi Zeni. "An Experimental Investigation on the Progressive Failure of Unsaturated Granular Slopes". Geosciences 9, n. 2 (29 gennaio 2019): 63. http://dx.doi.org/10.3390/geosciences9020063.
Testo completoAbstract (sommario):
Slope failure is a complex process which depends on several factors concerning nature and properties of soil, slope morphology and structure, past stress history, groundwater regime, boundary conditions, and their changes. As a consequence, the mechanism of slope failure is typically characterized by the development of a highly non-uniform strain field, which does not allow an easy prediction of the failure conditions. Usually, the process which will bring the slope to final collapse starts with local soil failure, which then leads to formation and propagation of a shear zone, and finally to general slope failure. This mechanical process is called progressive failure. However, in spite of the progresses in the knowledge of the slope behavior, a complete framework about the progressive failure is still missing; in particular, information about the response of granular unsaturated sloping soils is very poor. This paper reports the results of a couple of small-scale experiments on slopes reconstituted with unsaturated pyroclastic soils and subjected to continuous rainfall. The use of miniaturized sensors and optical fibers provided useful data to read some aspects of the mechanics of failure.
6
Hunter, Gavan, e Robin Fell. "Travel distance angle for "rapid" landslides in constructed and natural soil slopes". Canadian Geotechnical Journal 40, n. 6 (1 dicembre 2003): 1123–41. http://dx.doi.org/10.1139/t03-061.
Testo completoAbstract (sommario):
"Rapid" landslides in constructed and natural soil slopes have the potential to cause loss of life, destruction of property, and damage to the natural environment because the velocity of the slide mass is such that persons in the travel path do not have time to evacuate and the kinetic energy is such that even small landslides can severely damage buildings and other structures. This paper presents methods for prediction of the post-failure travel distance for "rapid" landslides from constructed cut and fill slopes and natural soil slopes derived from a database of some 350 "rapid" landslides in predominantly soil slopes. The characteristics of soils, both dilative and contractive on initial shearing, and the slope conditions for which landslides are susceptible to development into slides of "rapid" post-failure velocity are discussed. Methods for estimating the travel distance angle of the post-failure travel of the slide mass have been developed and are based on consideration of the failure mechanics of the initial slide (whether contractive or dilative on initial shearing), the type of slope, the slide volume, the geometry of the slope at and below the slide source area, and the degree of confinement of the travel path of the landslide.Key words: "rapid" landslide, flow slide, debris flow, debris slide, travel distance angle, failure mechanism.
7
Mburu, Joram Wachira, An-Jui Li, Horn-Da Lin e Chih-Wei Lu. "Investigations of Unsaturated Slopes Subjected to Rainfall Infiltration Using Numerical Approaches—A Parametric Study and Comparative Review". Sustainability 14, n. 21 (3 novembre 2022): 14465. http://dx.doi.org/10.3390/su142114465.
Testo completoAbstract (sommario):
In the past 30 years, research on rainfall-induced landslides has grown remarkably. The contribution of matric suction to soil strength and the physics of water flow in unsaturated soils are widely accepted phenomena among researchers. However, the adoption of unsaturated soil mechanics in geotechnical engineering practice has been relatively slow, in part due to the practicality of design solutions available to the engineer. This paper conducts a parametric study on unsaturated silty slopes under a vertical steady flow rate to identify the suitable slope and hydrologic conditions to incorporate unsaturated conditions for preliminary stability analysis. Notably, the contribution of suction is most significant for silt/clay slopes with a water table located below the mid-height of the slope. For slopes with slope height ≥20 m and a fairly high water table, the slope height is a primary controlling factor of slope stability. Two case studies based on distinct failure mechanisms are presented to review the application of common geotechnical software in rainfall seepage and stability analyses of unsaturated slopes. Focus is placed on the pre-failure and failure stages of each case study. The slip surface search method, failure mode, and coupling approach integrated into each computer program caused notable differences in output results.
8
Wang, Lei, Yongsheng Yao, Jue Li, Kefei Liu e Fei Wu. "A State-of-the-Art Review of Organic Polymer Modifiers for Slope Eco-Engineering". Polymers 15, n. 13 (29 giugno 2023): 2878. http://dx.doi.org/10.3390/polym15132878.
Testo completoAbstract (sommario):
In slope ecological restoration projects, reinforcing soil and promoting vegetation growth are essential measures. Guest soil spraying technology can be used to backfill modified soil and vegetation seeds onto the slope surface, resulting in successful ecological restoration. The use of organic polymer modifiers to reinforce soil has several benefits, such as high strength, effective results, and low pollution levels. Organic polymer soil modifiers can be divided into two categories: synthetic polymer modifiers and biopolymer modifiers. This paper provides a thorough review of the properties and interaction mechanisms of two types of polymer modifiers in soil consolidation. The properties of organic polymer modifiers make them applicable in soil and vegetation engineering on slopes. These modifiers can enhance soil mechanics, infiltration, and erosion resistance and promote vegetation growth. Therefore, the suitability of organic polymer modifiers for soil and vegetation engineering on slopes is demonstrated by their properties and potential for improvement in key areas. Furthermore, challenges and future prospects for slope protection technology using organic polymer modifiers are suggested.
9
A. N. Pluhin, L. V. Trikoz, O. S. Herasimenko, A. A. Pluhin, D. A. Pluhin e Al. A. Pluhin. "The development of some aspects of colloid chemistry and physicochemistry mechanics of disperse systems and materials are used in stability slopes". Science and Transport Progress, n. 39 (25 dicembre 2011): 150–56. http://dx.doi.org/10.15802/stp2011/6904.
Testo completoAbstract (sommario):
In the article the motive force of the movement the particles in dispersed systems, which include soils, when load is just sole weight of the array was investigated. It is shown that the shearing force of the weight of the soil and the specific cohesion which taken into account in calculating the stability of slopes of embankments and landslides on the slopes, much less than real. The calculations showed that the electrophoretic mechanism is a very real explanation of the observed sliding the upper part of the slope.
10
Lade, Poul V. "The mechanics of surficial failure in soil slopes". Engineering Geology 114, n. 1-2 (giugno 2010): 57–64. http://dx.doi.org/10.1016/j.enggeo.2010.04.003.
Testo completo
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Putra, Irza Tri, Guskarnali Guskarnali e Irvani Irvani. "APLIKASI SOFTWARE GEOSTUDIO 2007 SLOPE/WUNTUK ANALISIS KESTABILAN LERENG DI TAMBANG MUARA TIGA BESAR UTARA PT BUKIT ASAM (PERSERO) Tbk SUMATERA SELATAN". MINERAL 2, n. 2 (30 gennaio 2020): 78–89. http://dx.doi.org/10.33019/mineral.v2i2.1562.
Testo completoAbstract (sommario):
PT Bukit Asam (Persero) Tbk is one of the State Owned Enterprises engaged in coal mining. Presente of Mine Muara slopes at Muara Tiga Besar Utara would be harmful to workers and the mechanical vehicle, because the soil/ rock is likely to experience landslides or falling. This study was conducted to determine the value of slope safety factor RKAP 2017 and redesign the slopes with a safe condition. The data used in this study include the value of cohesion (c’) the angle of friction (ϕ’) and density (γ). Retrieval of research data obtained from the test results did not drainage unconsolidated triaxial (UU) and test weight of soil/rock with Paraffin Wax Method, and then did the processing of data by using Software Geostudio 2007 Slope/w to determine the value of the safety factor of the slope. Factors affecting slope instability in Mine Muara Tiga Besar Utara were the geometry of the slope, weather/climate, vibration, and physical properties and mechanics of soil/rock composed of the density (γ), ie 1.203 to 2.025 gr/cm3, the value of cohesion (c’), which is 34 to 266 kPa and the shear angle value (ϕ’), ie 17.65 to 35.210. The results of slope stability analysis indicate that the value of slope safety factor RKAP 2017 was below 1.25, so the potential occurrence of landslides, while the redesign slope slope with the security condition had a value of safety factor is above 1.25, so that no potential landslides.
12
Ghosh, Debayan, Aritra Banerjee, Anand J. Puppala e Prince Kumar. "Exploring the Influence of Climate Change on Earthen Embankments with Expansive Soil". Geosciences 14, n. 2 (30 gennaio 2024): 37. http://dx.doi.org/10.3390/geosciences14020037.
Testo completoAbstract (sommario):
Climate change is known to cause alterations in weather patterns and disturb the natural equilibrium. Changes in climatic conditions lead to increased environmental stress on embankments, which can result in slope failures. Due to wetting–drying cycles, expansive clayey soil often swells and shrinks, and matric suction is a major factor that controls the behavior. Increased temperature accelerates soil evaporation and drying, which can cause desiccation cracks, while precipitation can rapidly reduce soil shear strength. Desiccated slopes on embankments built with such soils can cause surficial slope failures after intense precipitation. This study used slope stability analysis to quantify how climate-change-induced extreme weather affects embankments. Historic extreme climatic events were used as a baseline to estimate future extremes. CMIP6 provided historical and future climatic data for the study area. An embankment was numerically modeled to evaluate the effect on slope stability due to the precipitation change induced by climate change. Coupled hydro-mechanical finite element analyses used a two-dimensional transient unsaturated seepage model and a limit equilibrium slope stability model. The study found that extreme climatic interactions like precipitation and temperature due to climate change may reduce embankment slope safety. The reduction in the stability of the embankment due to increased precipitation resulting from different greenhouse gas emission scenarios was investigated. The use of unsaturated soil strength and variation of permeability with suction, along with the phase transition of these earthen embankments from near-dry to near-saturated, shows how unsaturated soil mechanics and the hydro-mechanical model can identify climate change issues on critical geotechnical infrastructure.
13
Guo, Yanglin, e Chao Ma. "Elucidating the role of soil hydraulic properties on aspect-dependent landslide initiation". Hydrology and Earth System Sciences 27, n. 8 (20 aprile 2023): 1667–82. http://dx.doi.org/10.5194/hess-27-1667-2023.
Testo completoAbstract (sommario):
Abstract. Aspect-dependent landslide initiation is an interesting finding, and previous studies have attributed this to the mechanical effects of plant roots. In the present study, an overwhelming landslide probability on a south-facing slope over a north-facing slope was found in a localized area with only granite underneath and high cover of Larix kaempferi. These observations cannot be attributed to plant roots but may result from factors related to hillslope hydrology. Differential weathering associated with hillslope hydrology behaviors such as rainfall water storage and leakage, pore water pressure, particle component, and hillslope stability fluctuation were used to examine these observations. Remote sensing interpretation using the high-resolution GeoEye-1 image, digitalized topography, and field investigations showed that landslides on south-facing slopes have a higher probability, larger basal area, and shallower depth than those on a north-facing slope. The lower limits of the upslope-contributing area and slope gradient condition for south-facing landslides were less than those for north-facing landslides. The higher basal areas of south-facing landslides than those of the north-facing landslides may be attributed to the high peak values and slow dissipation of pore water pressure. The absorbed and drained water flow in a given time interval, together with the calculated water storage and leakage measured during the rainy season, demonstrate that the soil mass above the failure zone for south-facing slope is more prone to pore water pressure, which results in slope failures. In comparison, the two stability fluctuation results from the finite and infinite models further verified that landslides on south-facing slopes may fail under conditions of prolonged antecedent precipitation and intensive rainfall. Meanwhile, those on north-facing slopes may fail only in response to intensive rainfall. The results of this study will deepen our knowledge of aspect-dependent landslide initiation from both classical mechanics and the state of stress.
14
Liao, Hong Jian, Cheng Lin Tian e Hang Zhou Li. "Analysis of Slope Failure Mechanisms Considering Micropile-Soil Interaction". Key Engineering Materials 535-536 (gennaio 2013): 565–68. http://dx.doi.org/10.4028/www.scientific.net/kem.535-536.565.
Testo completoAbstract (sommario):
A large scale model test was carried out in loess slope, in which the stress and deformation characteristics of slopes reinforced with different arrangements of micropiles were studied. The mechanism of the micropile-soil interaction and the reinforcement effect of micropiles in loess slope were analysed. Based on the scale of in-situ loess slope and the physical mechanics parameters of loess soil, a numerical model was established by using finite difference method. For a reasonable arrangement of micropiles in step-shaped slope, the critical slip surfaces were determined considering the influence of slope inclination, ratio of step height and loading position. The micropiles were arranged in the step-shaped slope based on the critical slip surface, and the relationship between the ultimate bearing capacity of slope and shear strength parameters of loess soil was studied. The maximum shear strain of micropile-soil and moment of micropiles were calculated, and then the mechanism of the micropile-soil interaction was analysed.
15
Hrushetskiy, Hrushetskiy, Yuriy Pavelchuk, Ihor Babyn e Oleg Lyashuk. "MODELING OF TECHNOLOGICAL PROCESS OF SOWING GRAIN CROPS BY OPENERS FOR DIRECT SOWING ON SLOPE". ENGINEERING, ENERGY, TRANSPORT AIC, n. 2(117) (30 agosto 2022): 34–46. http://dx.doi.org/10.37128/2520-6168-2022-2-4.
Testo completoAbstract (sommario):
To date, sowing is one of the most urgent tasks, therefore, universal sowing equipment is widely in demand, which should ensure a uniform distribution of the number of plants per unit area to create the same conditions for development. Theoretical studies were carried out using the methods of theoretical mechanics, strength of materials, probability theory, mathematical analysis and modeling. Research is carried out on the basis of numerous implementations of the equations of continuum dynamics in applied engineering calculation programs - CAE systems. The article provides a theoretical analysis of the interaction of the soil layer with the surface of the working body of the seeder for the implementation of the technological process of sowing seeds of grain crops on the slopes. We have obtained a diagram of the forces acting on the soil during the working process, a diagram of the forces acting on the soil layer while moving along the slope, a diagram for determining the parameters of the working plane, initial and limiting conditions for the interaction of the working body with the soil environment, a diagram for determining the speed of the soil layer, a diagram changes in the speed of the soil layer on the slopes, the scheme of forces acting on the soil layer on the slopes, the dependence of the gravity force of the soil layer on the surface of the working body and the backing force on the angle of the slope, the dependence of the backing force on the angle. The initial and limiting conditions of the mathematical model of the technological process are considered, and a technique for implementing the mathematical model of the technological process of the work of the working body on slopes with different values of the angle of inclination of the working surface is developed. A mathematical model of the technological process of tillage on different types of agricultural landscapes by experimental working bodies has been developed. The initial and limiting conditions of the mathematical model of the technological process of processing are established, taking into account the slope of the working surface of the field.
16
Ladanyi, Branko. "Creep of frozen slopes and ice-filled rock joints under temperature variation". Canadian Journal of Civil Engineering 33, n. 6 (1 giugno 2006): 719–25. http://dx.doi.org/10.1139/l05-112.
Testo completoAbstract (sommario):
Owing to climate warming trends, there has been an increasing interest in recent years in the accelerating creep of rock glaciers and frozen slopes. In the field of glaciology, the creep of glaciers has been extensively studied, observed, and analyzed for more than 100 years. Many valuable and detailed theoretical models have been proposed through the years for simulating the creep behavior of glaciers. This synthesis paper has no intention of proposing another one. Its purpose is only to supply to these models a potential geotechnical background, borrowed from the connected fields of frozen ground mechanics, rock mechanics, and the mechanics of mixtures. In particular, this paper attempts to extend some known models of mechanical behavior of unfrozen soil and rock masses to masses containing ice and to apply these models to large-scale creep of ice–rock mixtures and ice–rock interface problems under variable temperature and stress conditions.Key words: ice, rock, mixture, rock joints, slope stability, creep, temperature.
17
Hou, Hengjun, Zhengwei Zhu, Bo Wang e Wenhao Zhou. "A Practical Model Study on the Mechanism of Clay Landslide under Static Loads: From the Perspective of Major Crack–Stress–Displacement". Applied Sciences 12, n. 7 (22 marzo 2022): 3224. http://dx.doi.org/10.3390/app12073224.
Testo completoAbstract (sommario):
Stability assessment of cracked clay slopes has been a research hotspot in geotechnical engineering in recent years. The assessment work should include crack initiation/development and stability evaluation. However, there has been no universal method for predicting crack evolution until now. In addition, scholars have paid little attention to the coupling relationship between the evolution of cracks and the progressive failure process of macroscopic clay slopes and have seldom studied the ubiquitous diagonal cracks in clay slopes. In this work, the stress mechanism for initiation and development of major cracks was derived based on unsaturated soil mechanics and critical state soil mechanics considering the tensile, compression, and shear properties of clay. The correctness of the proposed theory was verified by constructing a large-scale, arc-shaped slip surface clay slope model. In the model test, earth pressure cells and displacement gauge were employed to monitor development of stresses within the clay slope and horizontal displacement of the slope shoulder, respectively, under the set load sequence. The results showed that the stress mechanism proposed in this paper could judge not only vertical cracks but also diagonal cracks. Horizontal stresses near the primary crack appeared as a result of stress saltation. The locations and depths of the major cracks could be determined by analyzing the differences in horizontal stress between adjacent measuring points under the same load step. The development of major crack–horizontal stress–displacement had intrinsic consistency, and the initiation and development of major cracks aggravated changes in displacement and horizontal stresses. The perspective of major crack–stress–displacement is helpful to wholly grasp the progressive failure process of cracked clay slopes and provide a reference for prediction of clay landslides.
18
Karapa, Enos, Tri Harianto, A. B. Muhiddin e Rita Irmawaty. "Slope Reinforcement Model Scale Test With X-Block". Civil Engineering Journal 8, n. 3 (1 marzo 2022): 612–21. http://dx.doi.org/10.28991/cej-2022-08-03-014.
Testo completoAbstract (sommario):
This study aims to determine the material composition and dimensions of X-block, develop a slope reinforcement model using X-block, evaluate the mechanical behavior of slopes that are reinforced with rock-bound by X-block, and analyze the performance of slope reinforcement using X-block. This research was conducted at Hasanuddin University's soil mechanics and civil engineering structure laboratory. The model scale test was employed in this study. The geometrical speciation of the test box is 150 cm in length, 60 cm in width, and 100 cm in height. The X-block model was produced using concrete with a FC of 25 MPa. The X-block was divided into two types: X-block type 1 and X-block type 2. Tensile strength testing is performed on the X-block. The slopes are made of clay soil and have a slope angle of 70 degrees. The loading test was conducted in three stages: without block, with X-block type 1, and with X-block type 2. The loading test uses a hydraulic pump equipped with a load cell and LVDT. The tensile strength of X-block type 1 is 2.56 MPa, whereas X-block type 2 has a tensile strength of 4.35 MPa. The development of the type X-block design, which is used as a retaining wall material, has shown that it can effectively withstand landslides on the slopes under consideration. The slope safety factor rose dramatically after being reinforced with type X-blocks, reaching 2.73 for both X-block type 1 and X-block type 2. Doi: 10.28991/CEJ-2022-08-03-014 Full Text: PDF
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Smith, John Victor. "Interaction of Strength and Stress in High, Steep Rock Slopes". Journal of Geography and Geology 8, n. 1 (6 gennaio 2016): 14. http://dx.doi.org/10.5539/jgg.v8n1p14.
Testo completoAbstract (sommario):
The strength of rock mass and the stress in a slope are each complex fields of investigation. They are also intimately related as increasing confining stress makes a rock mass stronger and the strength of a rock mass can limit the magnitude of stress. Whereas these interactions are comparatively well understood for soils, principally through the advances of laboratory soil mechanics, the scale of rock masses, principally the presence of discontinuity surfaces, limits the capacity for laboratory investigation. The interaction of strength and stress in rock slopes is most evident in high, steep slopes where stress is typically greater. The slope angle and failure mechanisms occurring in the rock slope can reveal the ways that strength and stress interact to produce the observed morphology. McKay Bluff, near Nelson, South Island, New Zealand, is a high, steep rock slope affected by marine coastal erosion at its base. Finite element modeling illustrates sensitivities in determination of the stress magnitude in the slope. Engineering geology methods demonstrate the difficulty in precise determination of the rock mass strength. The ranges of these parameters are compared to find a compatible range for the interacting factors. The stress in a range of other high, steep slope types is reviewed and the implications for geomorphic analysis are discussed.
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Xiaolei, JI, XU Lanlan e YANG Guoping. "Influence of Root Morphology on Ecological Slope Protection". E3S Web of Conferences 198 (2020): 04036. http://dx.doi.org/10.1051/e3sconf/202019804036.
Testo completoAbstract (sommario):
Ecological slope protection is of great importance for preventing the water and soil loss on bare slopes, improving the ecological environment, and realizing the sustainable ecosystem development. The root-soil composite slope consisting of homogenous soil mass and oleander root system was taken as the study object. Based on the mechanics principle of soil reinforcement by roots in ecological slope protection, the influences of the lateral root quantity of plants and included angle between main root and lateral root on the slope protection were investigated via the finite element (FE) software ABAQUS. The simulation results show that the larger the quantity of lateral roots, the more obvious the displacement reduction of the soil mass on the slope surface will be. The slope protection effect varies with the root morphology, the included angle between main root and lateral root is an important factor influencing the slope protection effect of plants, and the slope protection effect at included angle of 30° is apparently superior to that at 90°. The research results can provide a theoretical support for the plant selection in the ecological slope protection.
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Francis, S. C. "The Limitations and Interpretation of the “Angle of Repose” in Terms of Soil Mechanics: a Useful Parameter?" Geological Society, London, Engineering Geology Special Publications 2, n. 1 (1986): 235–40. http://dx.doi.org/10.1144/gsl.1986.002.01.43.
Testo completoAbstract (sommario):
AbstractPrevious workers including Terzaghi (1943), Skempton (1945) and Lambe & Whitman (1979) have suggested that an “angle of repose” of a granular soil is approximately equal to ϕ′cv. Unfortunately a variety of definitions of different angles of repose exist, with up to six different angles having been identified. To minimise further confusion, it is recommended that the term should either be avoided or standardised.Following an evaluation of the variability of repose slopes, the findings of a detailed study of the relationship between this parameter and ϕ′cv for a variety of artificial and natural soils is presented, ϕ′cv measurements were made using both 60 mm and 100 mm shearboxes under wet and dry conditions at low confining stresses, and repose measurements were made both in air and under water. Overall, correlation between the two angles was good, with some of the scatter in results being attributable to identifiable soil particle characteristics.Observation of the repose slope during measurement gave a preliminary insight into avalanching mechanisms, which are more problematic than was expected. An explanation of repose slope behaviour is then proposed, which also provides an explanation of the similarity in slope angles of subaerial and subaqueous sand dunes. Practical implications of the correlation are then discussed.
22
Nasiri, Mehran, e Mojtaba Mohamadzade. "Cut slope stability assessment along forest roads using the limit equilibrium approaches and Slide software". Journal of Forest Science 68, No. 5 (26 maggio 2022): 182–89. http://dx.doi.org/10.17221/21/2022-jfs.
Testo completoAbstract (sommario):
Calculating the factor of safety (FS) as slope stability factor is necessary to prevent environmental damage. Therefore, this paper aims to (i) calculate FS using the limit equilibrium approaches and Slide software and (ii) investigate the stability of slopes according to calculated FS (Janbu and Bishop methods) and status of different sites in the study area (Hyrcanian forest of Iran). Six landslides were selected along the forest road by a field survey. Landslide dimensions including length, width, and height were measured using meters. Slope gradients were measured using the Suunto clinometer. The Slide software was used to evaluate the stability analysis of slopes. According to laboratory tests on soil samples the average of the liquid limit was recorded as 58%. The results of the direct shear test showed that the rate of soil cohesion (c) and coefficient of friction angle (φ) decreased with an increase in moisture content. According to the results, the factors of safety for landslide sites (Sites 1–6) were calculated to be 1.3, 0.65, 0.76, 0.55, 1.19 and 1.51, respectively. These calculated FS can accurately determine the slope status in terms of slope stability. According to the software classification, the status of Site 1 is “susceptible to landside”. Sites 2, 3 and 4 are “very high risk”. Also, the status of Sites 5 and 6 are “high risk” and “stable”, respectively. The instability of the slopes in studied sites is related to the drainage system (lack of culverts or ditches) as well as marlstone as bedrock. According to the calculated FS in different sites and comparison of the obtained results with the real conditions of sites, it can be concluded that the slope stability analysis in the Slide software is very accurate and it can be used to determine the factor of safety under different conditions in terms of morphology, hydrology and soil mechanics.
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Satyanaga, Alfrendo, Martin Wijaya, Qian Zhai, Sung-Woo Moon, Jaan Pu e Jong R. Kim. "Stability and Consolidation of Sediment Tailings Incorporating Unsaturated Soil Mechanics". Fluids 6, n. 12 (24 novembre 2021): 423. http://dx.doi.org/10.3390/fluids6120423.
Testo completoAbstract (sommario):
Tailing dams are commonly used to safely store tailings without damaging the environment. Sand tailings (also called Sediment tailings) usually have a high water content and hence undergo consolidation during their placement. As the sediment tailings are usually placed above the ground water level, the degree of saturation and permeability of the sediment tailing is associated with the unsaturated condition due to the presence of negative pore-water pressure or suction. Current practices normally focus on the analyses saturated conditions. However, this consolidation process requires the flow of water between saturated and unsaturated zones to be considered. The objective of this study is to investigate the stability and consolidation of sediment tailings for the construction of road pillars considering the water flow between saturated and unsaturated zones. The scope of this study includes the unsaturated laboratory testing of sediments and numerical analyses of the road pillar. The results show that the analyses based on saturated conditions overestimate the time required to achieve a 90% degree of consolidation. The incorporation of the unsaturated soil properties is able to optimize the design of slopes for road pillars into steeper slope angles.
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Al-Badran, Yasir, e Tom Schanz. "Volume change behavior of bentonite-sand mixture under constant suction condition". MATEC Web of Conferences 162 (2018): 01028. http://dx.doi.org/10.1051/matecconf/201816201028.
Testo completoAbstract (sommario):
The unsaturated state of soil can raise many geotechnical problems upon wetting-drying cycles such as volume change resulting in collapse or swell, change in the shear strength, and change in the hydraulic conductivity. The classical principles of soil mechanics for saturated soil are often not suitable for explaining these phenomena. An experimental work was carried out to study the volume change behavior of Bentonite-Sand mixture under constant suction condition. A mixture of 30% Calcigel bentonite and 70 % Haider sand (30B) were tested in this study. The applied suction was kept constant through the tests. Thirteen 30B specimens were tested under constant suction condition. Two different initial states (slurry and loose) were chosen to examine the effect of initial state on the volume change at unsaturated state. The results of first group (initially slurry state) show that once the suction was applied the compressibility of the specimens in this group followed the isotropic NCL up to 255 kPa suction. Subsequently, the slope of compression curve decreased. The results of increasing suction for initially slurry state show that the slope of compression lines became near to zero for suction higher than 600 kPa. Moreover, when applied suction is lower than the air-entry value, saev, the soil behaviors as the saturated soil. Therefore, the effective stress equation can be applied. The results of second group (initially loose state) show that the unsaturated preconsolidation pressure increases as the constant suction increases. The slopes of the unsaturated over consolidated paths in all tests were closed to the slope of saturated over consolidated path (Cr), while the slopes of the unsaturated normal consolidated (yield) state are higher than the slope of saturated NCL. Finally the results show that the slope of the unsaturated NCL is higher (steeper) than the slope of saturated NCL.
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Theocharis, Alexandros, Ioannis Zevgolis e Nikolaos Koukouzas. "Numerical analysis of rainfall effects on the slope stability of open pit coal mines". E3S Web of Conferences 382 (2023): 13006. http://dx.doi.org/10.1051/e3sconf/202338213006.
Testo completoAbstract (sommario):
As the world transitions away from coal, vast areas of closed coal mines and waste dumps must be appropriately reclaimed. One critical element for these areas’ safety is slope stability, given the massive slopes of these mines and dumps. This work examines the effect of extreme rainfall on coal mines’ slopestability by incorporating unsaturated soil mechanics principles in a practical way. Past extreme rainfall events recorded for a Greek lignite mining area were used, and climate projections concluded that this intensity is not expected to change. Then, rainfall infiltration was simulated using the Finite Element Method; a typical slope was employed concerning a lignite mining excavation of 200m height and 14° inclination on fine-grained soils. Finally, the stability was calculated using the Limit Equilibrium Method. Rainfall infiltration caused the Safety Factor to decrease, leading to failure. The groundwater rose at theslope’s face from the slope’s toe upwards and led to the development of a smaller and more local than the initial (before rainfall) sliding surface with a lower Safety Factor. Although this is a smaller surface than the initial one, it is still more than 50m high, proposing a significant hazard with severe consequences for the area.
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M, Sampath Kumar, e Dr Sreedhar M.V.S. "Application of Geo Textiles in Erosion Control – A Review Paper". International Journal of Engineering Research in Mechanical and Civil Engineering (IJERMCE) 9, n. 8 (1 agosto 2022): 28–33. http://dx.doi.org/10.36647/ijermce/09.08.a006.
Testo completoAbstract (sommario):
Geo textiles are a possible great alternative before vegetation establishes itself, and provides immediate control on soil erosion on different types of slopes. In this study, different geo textiles have been used for better erosion control over different soils. Different structurally modified geomeshes are tested for runoff erosion control, culmination discharge over different types of soils at different slope angles and at different rainfall intensities. Though these geo textile products are in use since a long time, the selection of product is mostly based on the manufacturer’s recommendations. Hence, there is a great necessity to understand the mechanics involved and to develop a comprehensive design methodology. In line with this, in the present study a review was done about the research takes place so far across the world.
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Chen, Guan-yi, Peng He, Gang Wang, Shang-qu Sun e Jie Xiao. "Shallow Layer Destruction Law of Expansive Soil Slope under Rainfall and the Application of Geogrid Reinforcement". Geofluids 2021 (8 luglio 2021): 1–14. http://dx.doi.org/10.1155/2021/6636894.
Testo completoAbstract (sommario):
A large number of instability cases and laboratory tests of expansive soil slopes show that its shallow layer destruction happens because of the insufficient shear strength under the usual action of low stress and repeated dry-wet cycles. We can obtain the strength nonlinear distribution law fitted by generalized power function based on a series of shear strength tests of expansive soil considering low stress and can construct the numerical model considering the nonlinear strength distribution by FISH, to realize the shear strength dynamic distribution with the vertical stress. Based on the numerical model, the whole-process contrastive analysis has been conducted on the stress field, the slip surface depth, and the seepage field of plain soil and reinforced expansive soil cut slope under different rainfall conditions. Besides, the mechanics characteristic of the geogrid under various design schemes has been compared and analyzed. A further explanation has been given for the expansive soil cut slope prone to shallow layer failure after rainfall and on the effect of geogrid reinforcement. The numerical results provide a reference for slope stability analysis in rainy expansive soil areas.
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Li, Shaoling, Chi Qiu, Jiankun Huang, Xiaoping Guo, Yucun Hu, Al-Shami Qahtan Mugahed e Jin Tan. "Stability Analysis of a High-Steep Dump Slope under Different Rainfall Conditions". Sustainability 14, n. 18 (6 settembre 2022): 11148. http://dx.doi.org/10.3390/su141811148.
Testo completoAbstract (sommario):
The existing slope stability research, which is based on the fluid–solid coupling theory, is mainly focused on the slopes of central and eastern China. The impact of rainfall on the stability of the dump slope has often been ignored. It is worthwhile to reveal the mechanism of the fluid–solid coupling mechanics of dump slopes in the arid desertification area of northwest China under the maximum precipitation. The method of combining the seepage mechanics theory with the geomechanics theory was adopted. Darcy’s law and the mass conservation law were introduced to derive and establish the fluid–solid coupling analysis method. Taking the Xinxing Coal Mine in Wuhai City, China, as an example, the finite element software ABAQUS was used to construct the fluid–solid coupling model for slope stability analysis with unsaturated soil. The equivalent rainfall intensity of 68 mm/h for 1 h and 18 mm/h for 24 h was designed in the simulation, respectively. Four different types of initial water content (i.e., 1.72%, 7.34%, 14.69%, and 22.03%) of the dump slopes were defined as the initial conditions. The high-steep slope was compared to the standard slope. Therefore, a set of sixteen rainfall schemes was proposed. The variation regularity of slope stability was thoroughly discussed in regards to four areas: vertical deformation, pore water pressure distribution, equivalent plastic strain, and safety factor. As was expected, the research showed that the slope height and angle have a significant effect on the slope stability. When high-intensity rainfall occurs for a short duration, the slope tends to be more stable as the initial water content increases on the slope. When low-intensity rainfall occurs over a long period, the slope stability reduces if the initial water content is too high or too low in the slope.
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Michalowski, Radoslaw L., e Dowon Park. "Three‐dimensional ridge collapse mechanism for narrow soil slopes". International Journal for Numerical and Analytical Methods in Geomechanics 45, n. 13 (18 giugno 2021): 1972–87. http://dx.doi.org/10.1002/nag.3251.
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Xiao, Shiguo, Tingju Chen e Wei Dong Guo. "Bearing capacity of rigid strip footings near soil slopes". Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics 173, n. 4 (dicembre 2020): 173–87. http://dx.doi.org/10.1680/jencm.18.00045.
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McGreal, W. S., e D. Craig. "Mass-movement activity: an illustration of differing responses to groundwater conditions from two sites in Northern Ireland". Irish Geography 10, n. 1 (26 dicembre 2016): 28–35. http://dx.doi.org/10.55650/igj.1977.851.
Testo completoAbstract (sommario):
Field investigation of slope failure in north-eastern Ireland, at Kilkeel, Co. Down, and Minnis North, Co. Antrim, suggests that groundwater level is an important factor influencing the incidence of failure. However, the pattern of mass-movement in slopes of glacial origin at Kilkeel compared to the Lias clays of Minnis North implies that different types of mass-movement demonstrate different responses to general groundwater conditions. These observations indicate that the traditional formulas used by geomorphologists for soil mechanics problems may need to be modified with respect to the observed character of groundwater conditions.
32
Stille, Håkan, Bruce Ashcroft, Conrad Boley, Vincent Labiouse e Paulo Pinto. "Felsmechanische Planung in der geotechnischen Werkzeugkiste von morgen: Eurocode 7 – Geotechnische Bauwerke: Böschungen, Flachgründungen und Stützkonstruktionen (EN 1997‐3:2024)". Geomechanics and Tunnelling 16, n. 5 (ottobre 2023): 524–35. http://dx.doi.org/10.1002/geot.202300025.
Testo completoAbstract (sommario):
AbstractThe second generation of Eurocode 7 includes both soil and rock. In addition to the current practice of ground engineering, this document aims at incorporating rock engineering, improving the ease of use, the harmonization of regulations and covering new developments. This paper provides an overview of some of the significant changes to Eurocode 7 in rock engineering design, taking into consideration limit state design, robustness, durability, and reliability. It focuses on the design of slopes, spread foundations, and retaining structures.The clauses focus on soil mechanics, but also include special rock mechanical issues such as the influence of discontinuities and strength anisotropy on the limit states. Many matters associated to verification of rock mechanical design are linked to the use of prescriptive rules and shall be given in National Annexes. For geotechnical structures in rock, it is mentioned that geotechnical mapping and documentation is important to verify the limit states. However, the basic issues with partial factor methods for verification of the ground‐structure interaction of reinforced slopes and retaining structures are not fully resolved. This has caused some difficulties in setting up partial factors and obtaining a sufficient overview of the application of partial factor method, especially in rock engineering.The design of slopes, spread foundations and retaining structures must likewise consider other clauses in the Eurocode. Rock support for slopes and retaining structures is described in Clause 13 ”Rock Bolts and Surface Support“. Groundwater‐related issues are described in clause 12 ”Ground water control“ which influence the design and limit states for the actual geotechnical structure. Dams and levees are featured in Clause 4 ”Slopes, Cuttings and Embankments“.
33
Operstein, V., e S. Frydman. "The stability of soil slopes stabilised with vegetation". Proceedings of the Institution of Civil Engineers - Ground Improvement 6, n. 4 (gennaio 2002): 163–68. http://dx.doi.org/10.1680/grim.2002.6.4.163.
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Operstein, V., e S. Frydman. "The stability of soil slopes stabilised with vegetation". Ground Improvement 6, n. 4 (dicembre 2002): 163–68. http://dx.doi.org/10.1680/grim.6.4.163.40918.
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Kacimov, A. R., e Yu V. Obnosov. "Analytical Determination of Seeping Soil Slopes of a Constant Exit Gradient". ZAMM 82, n. 6 (giugno 2002): 363. http://dx.doi.org/10.1002/1521-4001(200206)82:6<363::aid-zamm363>3.0.co;2-5.
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Gan, JianJun, e Y. X. Zhang. "Analysis of Model Tests of Rainfall-Induced Soil Deposit Landslide". Advances in Civil Engineering 2020 (22 luglio 2020): 1–13. http://dx.doi.org/10.1155/2020/6431247.
Testo completoAbstract (sommario):
A large number of deposit landslides are induced by rainfall, and those with different weak layers may be subject to catastrophic failure. This research investigates the rainfall infiltration effect on the stability of deposit landslides with a weak layer at different slope angles. Four rainfall physical model tests were conducted with fixed double penetration artificial rainfall technique and dynamic sensor technologies by using the rainfall test methods as modified in the paper. Deformation and mechanics parameters, as well as water content parameters in the key position in the deposit landslide, were monitored by means of various displacement monitoring sensors, dynamic soil pressure sensors, pore water pressure (PWP) monitoring sensors, and water content sensors. The results show that, under the same rainfall conditions, the rule of displacement and mechanical changes of deposit slope with different angles are similar, that the displacement, soil pressure, and PWP are characterized by two stages of rising and falling, and that the displacement of deposit slope with weak layer remains creep after rainfall. In addition, the displacement at the rear edge of the slope with a small angle is larger than that at the front of the steep slope, but the displacement in the front of the slope is opposite. Furthermore, the slope with a smaller angle is prone to form a tensile crack in the back of the slope, and its deformation and failure have the characteristics of a progressive and thrust-type landslide. While the failure in front of a steep slope (slope angle more than 60°) occurred first, the slope failure was characterized by sudden and retrogressive modes. The mathematical analysis of the model is also conducted which shows that deformation and failure can be divided into three stages, i.e., creep inoculation, accumulation uplift, and speed-up sliding. The test results can provide a reference for the investigation, design, and assessment of similar deposit slopes.
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Picarelli, L., G. Urciuoli, A. Mandolini e M. Ramondini. "Softening and instability of natural slopes in highly fissured plastic clay shales". Natural Hazards and Earth System Sciences 6, n. 4 (14 giugno 2006): 529–39. http://dx.doi.org/10.5194/nhess-6-529-2006.
Testo completoAbstract (sommario):
Abstract. Softening is often considered to be the main cause of first-time slides in OC clay, but so far the mechanics of softening has not been satisfactorily explained. Bearing on laboratory data and field observations about landslides in tectonized highly plastic clay shales of Italian Apennines, the paper describes a process of soil weakening that could explain some failures of natural slopes.
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Sabhahit, N., P. K. Basudhar e Madhira R. Madhav. "A generalized procedure for the optimum design of nailed soil slopes". International Journal for Numerical and Analytical Methods in Geomechanics 19, n. 6 (giugno 1995): 437–52. http://dx.doi.org/10.1002/nag.1610190605.
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Quinn, P. E., M. S. Diederichs, R. K. Rowe e D. J. Hutchinson. "Development of progressive failure in sensitive clay slopes". Canadian Geotechnical Journal 49, n. 7 (luglio 2012): 782–95. http://dx.doi.org/10.1139/t2012-034.
Testo completoAbstract (sommario):
The development of progressive failure in sensitive clay slopes is analysed using principles from fracture mechanics, where failure stress depends on a material property (toughness) and length of an existing weakness, unlike traditional soil mechanics where failure stress is generally assumed to be only a function of material strength. An existing weakness, or partially developed failure surface, can propagate due to sudden loads, as might be induced by seasonal erosion cycles, small local landslides at a river bank or earthquake shaking. The paper examines the growth of the failure surface over time due to such loads. The analysis shows that a large landslide in sensitive clay can occur after a number of seasonal erosion cycles with no obvious trigger. It also shows that a larger load due to either a small landslide or earthquake can cause a developing failure surface to propagate freely toward general collapse. Large landslides in sensitive clay are often preceded by a smaller landslide at the river bank, but can be triggered by large earthquakes or may occur for no obvious reason. The agreement between predictions and real behaviour suggests that the model for progressive failure of large landslides in sensitive clay deserves further consideration.
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Bulolo, Sam, e Eng Choon Leong. "Modelling shear strength of compacted soils". E3S Web of Conferences 92 (2019): 15007. http://dx.doi.org/10.1051/e3sconf/20199215007.
Testo completoAbstract (sommario):
Compacted soils constitute most engineering projects such as earth dams, embankments, pavements, and engineered slopes because of their high shear strength and low compressibility. The shear strength of compacted soils is a key soil parameter in the design of earth structures but it is seldom determined correctly due to their unsaturated state. The shear strength of compacted soils can be better evaluated under the framework of unsaturated soil mechanics. Saturated and unsaturated tests were conducted on compacted specimens using conventional direct shear apparatus under constant water content condition. Tests were conducted at different water contents and net normal stresses. The main objective of this study is to develop a shear strength model for compacted soils. Initial matric suction was measured before the test using the filter paper method. The two-stress state variables together with the extended Mohr-Coulomb failure criterion for unsaturated soils were used to obtain a lower bound model of the shear strength. The model was demonstrated using published data.
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Scotto di Santolo, A., A. M. Pellegrino e A. Evangelista. "Experimental study on the rheological behaviour of debris flow". Natural Hazards and Earth System Sciences 10, n. 12 (7 dicembre 2010): 2507–14. http://dx.doi.org/10.5194/nhess-10-2507-2010.
Testo completoAbstract (sommario):
Abstract. A model able to describe all the processes involved in a debris flow can be very complex owing to the sudden changing of the material that turns from solid into liquid state. The two phases of the phenomenon are analysed separately referring to soil mechanics procedures with regard to the trigger phase, and to an equivalent fluid for the post-failure phase. The present paper is devoted to show the experimental results carried out to evaluate the behaviour assumed by a pyroclastic-derived soil during the flow. A traditional fluid tool has been utilized: a standard rotational rheometer equipped with two different geometries. The soils tested belong to deposits that cover the slopes of the Campania region, Italy, often affected by debris flows. The influence of solid concentration Cv and grain size distribution was tested: the soils were destructurated, sieved and mixed with water starting from the in situ porosity. All material mixtures showed a non-Newtonian fluid behaviour with a yield stress τy that increases with a solid volumetric concentration and decreases for an increase of sand fraction. The experimental data were fitted with standard model for fluids. A simple relation between Cv and τy was obtained. The yield stress seems to be a key parameter for describing and predicting the post-failure behaviour of debris flows. These results suggest that in the field a small change in solid fraction, due to rainfall, will cause a slight decrease of the static yield stress, readily inducing a rapid flow which will stop only when the dynamic yield stress is reached, namely on a much smoother slope. This can explain the in situ observed post-failure behaviour of debris flows, which are able to flow over very long distances even on smooth slopes.
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Kang, Xing-Pei, Ya-Fei Wang, Zhan-Rong Zhang, Hao Xie e Yun Yang. "3D Limit Equilibrium Stability Analysis of Concave and Convex Slopes Considering Kinematic Constraints". Shock and Vibration 2022 (18 agosto 2022): 1–15. http://dx.doi.org/10.1155/2022/1625765.
Testo completoAbstract (sommario):
In the previous limit equilibrium stability analyses of concave and convex slopes, the kinematic constraints are not considered in the generation of slip surfaces. To tackle this problem, this technical note proposes a method to compute safety factors of concave and convex slopes, combining the simplified Bishop method with an adaptive “point-by-point” technique. Through the adaptive “point-by-point” technique, the failure surfaces of slopes are linked by numerous lines that connect two neighboring discretized points, at which the velocity compatibilities are strictly satisfied. Stress analyses are made for the vertical discretized slices where the lateral pressure on the interface between soil slices is represented by the Rankine active earth pressure. Based on the simplified Bishop method and the strength reduction method, the safety factor and failure surfaces of concave and convex slopes are derived, which are verified by numerical simulations. Comparative outcomes show that the results would be closer to those of numerical simulations if the strength reduction is made for the Rankine active earth pressure on the interface between soil slices. And the proposed discretized slip surface considering kinematic constraints is more consistent with the shear bands by numerical simulation, as compared with the circular arc slip surface. Under homogeneous soil conditions, the proposed discretized slip surface can degenerate into a logarithmic spiral.
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Schwarz, M., F. Giadrossich e D. Cohen. "Modeling root reinforcement using a root-failure Weibull survival function". Hydrology and Earth System Sciences 17, n. 11 (6 novembre 2013): 4367–77. http://dx.doi.org/10.5194/hess-17-4367-2013.
Testo completoAbstract (sommario):
Abstract. Root networks contribute to slope stability through complex interactions with soil that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamics of root turnover, the quantification of root reinforcement on steep slopes is challenging and consequently the calculation of slope stability also. Although considerable progress has been made, some important aspects of root mechanics remain neglected. In this study we address specifically the role of root-strength variability on the mechanical behavior of a root bundle. Many factors contribute to the variability of root mechanical properties even within a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field data sets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the equations of the tensile force, the elasticity of the roots, and the root distribution are the most important steps. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows for the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.
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Wang, Long, Wei Hu, De'an Sun e Lin Li. "3D stability of unsaturated soil slopes with tension cracks under steady infiltrations". International Journal for Numerical and Analytical Methods in Geomechanics 43, n. 6 (20 gennaio 2019): 1184–206. http://dx.doi.org/10.1002/nag.2889.
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Σφέικος, A., Θ. Στιμάρατζης, A. Κίλιας e Β. Χρηστάρας. "BEHAVIOR OF PINDOS LIMESTONE DURING HIGH SLOPE EXCAVATION. AN APPROACH TO INTERPRETE AND SIMULATE THE BEHAVIOR OF THE FORMATION USING SLOPE STABILTY ANALYSIS METHODS". Bulletin of the Geological Society of Greece 36, n. 4 (1 gennaio 2004): 1853. http://dx.doi.org/10.12681/bgsg.16659.
Testo completoAbstract (sommario):
The Acheloos river diversion project includes also works which improve the condition of the infrastructure network in the area. One of them was the improvement of a section at the Mouzaki - Arta national road. The road is developed through geological formations of the Pindos Zone. In the Argithea area, Karditsa County, it cuts through Cretaceous limestone bearing Calpionella. This formation develops high and steep slopes, over 50 m high. It consists of thin to medium bedded limestone, showing locally chert intercalations, and gradational transition to siliceous limestone. Thin silt or clay layers separate bedding. The formations is strongly folded and intensively jointed. The initial design proposed the construction of a slope with H:V relationship of 1:4 and benches every 20 m. The designed geometry was during and soon after excavation destroyed, due to sliding of rock particles. A new geometry was developed possessing a more stable state of dynamic equilibrium. Our task is to investigate and simulate the behavior of this formation. Based on data from both laboratory analysis and literature we ascribed the limestone formation values for its geotechnical properties. Using these values we estimate the values for the Safety Factor for the geometrical features of the slope. We control the stability of the slope using both rock mechanics and soil mechanic methods. The results point that rock formations, like the Cretaceous limestone which exhibit variation in their composition, and high contrast between the geotechnical characteristics values of the composing elements, may be considered as a material with soil properties. The Safety Factor calculation using these assumptions for the above mentioned slope, resulted a geometry close to the one developed. Therefore we conclude that such rock material and formations may successfully be simulated as materials with soil geotechnical behavior.
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Deepa, V., e B. V. S. Viswanadham. "Centrifuge model tests on soil-nailed slopes subjected to seepage". Proceedings of the Institution of Civil Engineers - Ground Improvement 162, n. 3 (agosto 2009): 133–44. http://dx.doi.org/10.1680/grim.2009.162.3.133.
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Rahardjo, H., V. A. Santoso, E. C. Leong, Y. S. Ng, C. P. H. Tam e A. Satyanaga. "Use of recycled crushed concrete and Secudrain in capillary barriers for slope stabilization". Canadian Geotechnical Journal 50, n. 6 (giugno 2013): 662–73. http://dx.doi.org/10.1139/cgj-2012-0035.
Testo completoAbstract (sommario):
A capillary barrier is a two-layer cover system having distinct hydraulic properties to minimize water infiltration into the underlying soil by utilizing unsaturated soil mechanics principles. In this study, a capillary barrier system was designed as a cover system for a residual soil slope to maintain stability of the slope by minimizing infiltration during heavy rainfalls in the tropics. The capillary barrier system (CBS) was constructed using fine sand as the fine-grained layer and recycled crushed concrete aggregates as the coarse-grained layer. The coarse-grained layer is commonly constructed using gravels or granite chips. However, due to scarcity of aggregates and in consideration of environmental sustainability, recycled crushed concrete aggregates were used as the coarse-grained layer in this project. The suitability of recycled crushed concrete aggregates as a material within the coarse-grained layer of a CBS is subject to the hydraulic property requirement. For comparison, another CBS was constructed using fine sand as the fine-grained layer and a geosynthetic (Secudrain) as the coarse-grained layer. The performance of each constructed CBS on the residual soil slope was monitored using tensiometers installed at different depths — from 0.6 to 1.8 m below the slope surface — and a rainfall gauge mounted on the slope. An adjacent original slope without the CBS was also instrumented using tensiometers and piezometers to investigate the performance and effectiveness of the CBS in reducing rainwater infiltration and maintaining negative pore-water pressures in the slope. Real-time monitoring systems were developed to examine pore-water pressure, rainfall, and groundwater level in the slopes over a 1 year period. Characteristics of pore-water pressure distributions in the residual soil slope under a CBS with recycled crushed concrete aggregates and in the original slope during typical rainfalls are highlighted and compared. The measurement results show that the CBS was effective in minimizing rainwater infiltration and therefore, maintaining stability of the slope.
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D.N. Sharma, Ziaullah Shareef e K.K. Sharma. "Soil and Rock Mechanics Investigations for the Assessment of Strata Behaviour of an Opencast Coal Mine". Global Journal of Earth Science and Engineering 2, n. 1 (30 giugno 2015): 7–13. http://dx.doi.org/10.15377/2409-5710.2015.02.01.2.
Testo completoAbstract (sommario):
Abstract: The Singareni Collieries Company Limited (SCCL) planned for deepening the Opencast projects from the present depth of 250m to 400m. For successful operation and forecasting of strata behaviour in pre-mining was recognized. In this direction, SCCL had tie-up with CSIRO, Australia to work jointly, with a lead research provider. As part of these studies, to meet the requirement of generating needy data to conduct Numerical Modelling, extensive program was organized to take up different Physico Mechanical Properties (PMP) tests. In light of this, different tests suggested were taken up in SCCL and NIRM laboratories. The data thus generated were analyzed statistically to make use of the same for Numerical Modelling by CSIRO, Australia. The data generated during the course of organizing different tests, are synthesized and discussed in this paper. The paper deals with the methodology evolved in generation of desired soil and Rock Mechanics data to assess the stability of pit slopes, internal dump and OB dumps.
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Poulos, Harry G. "Design of reinforcing piles to increase slope stability". Canadian Geotechnical Journal 32, n. 5 (1 ottobre 1995): 808–18. http://dx.doi.org/10.1139/t95-078.
Testo completoAbstract (sommario):
This paper describes an approach for the design of piles to reinforce slopes, involving three main steps: (1) evaluating the shear force needed to increase the safety factor to the desired value; (2) evaluating the maximum shear force that each pile can provide to resist sliding of the potentially unstable portion of the slope; and (3) selection of the type and number of piles, and the most suitable location of these piles within the slope. For step 1, stability analyses can be used to assess the required additional shear force for stability. Step 2 involves the use of a computer analysis for the response of a pile to laterally moving soil. This analysis can be implemented via a computer program ERCAP, and enables the resisting shear force developed by the piles to be evaluated as a function of pile diameter and flexibility and the relative depth of the soil movement in relation to the pile length. Step (3) involves the use of engineering judgement in conjunction with the analysis results from steps 1 and 2. The paper describes the ERCAP analysis and the characteristics of pile behaviour it reveals. The application of the approach to a highway bypass problem in Newcastle, Australia, is described in detail. In the final design, a total of 64 bored piles 1.2 m in diameter were used over a total length of slope cutting of about 250 m. The pile lengths ranged between 6 and 12 m, with the spacings varying between 3.2 and 6.0 m. Key words : analysis, boundary element, piles, soil–pile interaction, slope stabilization, soil mechanics.
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Chen, Jian, Jian-Hua Yin e C. F. Lee. "Rigid Finite Element Method for Upper Bound Limit Analysis of Soil Slopes Subjected to Pore Water Pressure". Journal of Engineering Mechanics 130, n. 8 (agosto 2004): 886–93. http://dx.doi.org/10.1061/(asce)0733-9399(2004)130:8(886).
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