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1
Zhu, Wei, Liang Gao, Yingai Zhao, Chao Yang, Wei Sun und Pengqiang Yu. „Stability Analysis of Jointed Rock Cutting Slope Based on Discrete Element Method“. Advances in Civil Engineering 2022 (16.07.2022): 1–10. http://dx.doi.org/10.1155/2022/4915820.
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The joints in the rock mass are essential for the stability of rocky slopes, and the destabilization damage of the slope is often directly related to the joints. In this study, in order to reveal the instability process and mechanism of rock slopes from a microscale perspective, the DEM simulations for rocky slopes of the K88 + 400∼K88 + 540 section of Zhongkai Expressway are carried out considering the influence of joints. Based on the findings of the on-site jointed structural surfaces, a rocky slope model containing two sets of intermittent joints was constructed, and the linear parallel bond model and the smooth joint model are used to characterize the rock body and joints, respectively. The evolution of microfracture, contact force chain, and particle displacement are analyzed to explore the micromechanism of slope instability. Finally, the triple reinforcement scheme of anchor cable frame and grass planting is proposed. The research results can provide a reference for stability analysis and reinforcement of similar rocky slope projects.
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Shevchuk, Ruslan, Volodymyr Filipovych, Anton Mychak und Mykola Lybskyi. „Satellite monitoring features of crystalline rocks mining territories within Zhitomyr region based on optical and radar remote sensing data“. Ukrainian journal of remote sensing, Nr. 22 (01.10.2019): 12–21. http://dx.doi.org/10.36023/ujrs.2019.22.157.
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Opportunities of optical and radar satellite data application for ecological state and reclamation quality assessment of disturbed by crystalline rocks open cast mining lands are considered in the article. Digital elevation models analysis is proposed for the problem of identification of mines among rock dumps and rocky outcrops solution. Radar interferograms were used as source data for DEM creating. The research was performed on three study sites within Korostishiv, Cherniahiv and Khoroshiv districts of Zhitomir region. As result of the study an abandoned quarry with no reclamation done and an illegal stone processing waste dump were found. It is stated that environmental impact of crystalline rock open cast mining not as serious as ilmenite or amber open cast mining impacts and facts of violation of law caused by mining activities were not found.
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Laptev, V. V. „Numerical modelling of fragmented mined rock flow during ore drawing using the ROCKY DEM programme“. Vestnik MGTU 22, Nr. 1 (März 2019): 149–57. http://dx.doi.org/10.21443/1560-9278-2019-22-1-149-157.
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Liu, J., G. Q. Zhou, B. Jia, T. Yue und X. Y. Peng. „KARST ROCKY DESERTIFICATION ANALYSIS BASED ON HISTORICAL DISP DATA TAKE TWO REGIONS FOR EXAMPLE“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W10 (08.02.2020): 871–74. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w10-871-2020.
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Abstract. Karst rocky desertification (KRD) is used to characterize the processes that transform a karst area covered by vegetation and soil into a rocky landscape almost devoid of soil and vegetation. This situation seriously affects and threatens the living environment and standards of local people, which results in a series of social problems. In view of the importance and harmfulness of KRD, many scholars have studied the spatial and temporal evolution of KRD and its driving forces. In this paper, the Visual Interpretation Marks of Rocky Desertification in Southwest China in 1960s are constructed by using the DISP image of the United States, combined with DEM data and Hydrogeological data. The area of rocky desertification in Guangnan and Funing counties, where rocky desertification is more serious, is about 2457.729 km2. The area of rocky desertification can be used as the basic data for studying the historical changes in southwestern China by researchers.
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Lvov, Vladislav, und Leonid Chitalov. „Semi-Autogenous Wet Grinding Modeling with CFD-DEM“. Minerals 11, Nr. 5 (01.05.2021): 485. http://dx.doi.org/10.3390/min11050485.
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The paper highlights the features of constructing a model of a wet semi-autogenous grinding mill based on the discrete element method and computational fluid dynamics. The model was built using Rocky DEM (v. 4.4.2, ESSS, Brazil) and Ansys Fluent (v. 2020 R2, Ansys, Inc., United States) software. A list of assumptions and boundary conditions necessary for modeling the process of wet semi-autogenous grinding by the finite element method is presented. The created model makes it possible to determine the energy-coarseness ratios of the semi-autogenous grinding (SAG) process under given conditions. To create the model in Rocky DEM the following models were used: The Linear Spring Rolling Limit rolling model, the Hysteretic Linear Spring model of the normal interaction forces and the Linear Spring Coulomb Limit for tangential forces. When constructing multiphase in Ansys Fluent, the Euler model was used with the primary phase in the form of a pulp with a given viscosity and density, and secondary phases in the form of air, crushing bodies and ore particles. The resistance of the solid phase to air and water was described by the Schiller–Naumann model, and viscosity by the realizable k-epsilon model with a dispersed multiphase turbulence model. The results of the work methods for material interaction coefficients determination were developed. A method for calculating the efficiency of the semi-autogenous grinding process based on the results of numerical simulation by the discrete element method is proposed.
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Yao, M., G. Zhou, W. Wang, Z. Wu, Y. Huang und X. Huang. „STUDY ON KARST INFORMATION IDENTIFICATION OF QIANDONGNAN PREFECTURE BASED ON RS AND GIS TECHNOLOGY“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (30.04.2018): 2121–25. http://dx.doi.org/10.5194/isprs-archives-xlii-3-2121-2018.
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Karst area is a pure natural resource base, at the same time, due to the special geological environment; there are droughts and floods alternating with frequent karst collapse, rocky desertification and other resource and environment problems, which seriously restrict the sustainable economic and social development in karst areas. Therefore, this paper identifies and studies the karst, and clarifies the distribution of karst. Provide basic data for the rational development of resources in the karst region and the governance of desertification. Due to the uniqueness of the karst landscape, it can’t be directly recognized and extracted by computer in remote sensing images. Therefore, this paper uses the idea of “RS + DEM” to solve the above problems. this article is based on Landsat-5 TM imagery in 2010 and DEM data, proposes the methods to identify karst information research what is use of slope vector diagram, vegetation distribution map, distribution map of karst rocky desertification and other auxiliary data in combination with the signs for human-computer interaction interpretation, identification and extraction of peak forest, peaks cluster and isolated peaks, and further extraction of karst depression. Experiments show that this method achieves the “RS + DEM” mode through the reasonable combination of remote sensing images and DEM data. It not only effectively extracts karst areas covered with vegetation, but also quickly and accurately locks down the karst area and greatly improves the efficiency and precision of visual interpretation. The accurate interpretation rate of karst information in study area in this paper is 86.73 %.
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Lee, Hoseung, Jihyun Moon und Hoonyol Lee. „Activity of Okgye Limestone Mine in South Korea Observed by InSAR Coherence and PSInSAR Techniques“. Remote Sensing 14, Nr. 24 (10.12.2022): 6261. http://dx.doi.org/10.3390/rs14246261.
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The Okgye limestone mine, which is the largest open-pit limestone mine located in a mountainous area in Korea, suffered a collapse in 2012 that claimed four casualties. Restoration work on the rocky mined-out slopes, as well as mining and dumping activities, are still in progress. Monitoring slope stability is important to prevent the sudden collapse of slopes, which can be efficiently performed by satellite-based interferometric synthetic aperture radar (InSAR) techniques. Firstly, we obtained elevation changes using InSAR-generated Copernicus 30 m DEM in 2014 and an SRTM 1Sec DEM in 2000, through which the area was roughly classified into the mining area, tailings storage area, and the mined-out area. A time series of 12-day coherence images produced by Sentinel-1B SAR were averaged annually to produce an RGB-composite image to observe the change in mining activities during 2018, 2019, and 2020. We found many persistent scatterers (PS) when observing the ground displacement, both in the ascending and descending orbits, from which we decomposed this into the vertical and east components. The largest displacement of 63.6 mm/year was observed during 2019 and 2020 in the tailings storage area in the direction of the dumping slope. For the rocky outcrops and the transmission tower, we found a seasonal oscillation, which can be interpreted as the thermal expansion of limestone and iron. This paper demonstrated that the surface stability and deformation of open-pit mines could be effectively monitored by combining InSAR DEM, coherence, and PSInSAR techniques.
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Piacentini, Daniela, Francesco Troiani, Davide Torre und Marco Menichetti. „Land-Surface Quantitative Analysis to Investigate the Spatial Distribution of Gravitational Landforms along Rocky Coasts“. Remote Sensing 13, Nr. 24 (09.12.2021): 5012. http://dx.doi.org/10.3390/rs13245012.
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The increasing availability of high-quality digital elevation models (DEMs) has been associated with a growing interest in developing quantitative analyses aimed at taking advantage of these detailed, updated, and promising digital datasets. Land-surface quantitative (LSQ) analysis is valuable for describing the land-surface topography and performing measures of the signature of specific geomorphic processes, taking into account site-specific geological contexts and morphoclimatic settings, proving to be particularly effective in transitional environments, such as rocky coasts. This paper presents the results of research aimed at investigating the spatial distribution of gravitational landforms along rocky coasts, by means of LSQ analysis based on a DEM with a ground resolution of 2 m, derived from airborne LiDAR (light detection and ranging) surveys. The study area is at Mt. San Bartolo (Northern Marche, Italy) and characterized by a sea cliff diffusely affected by gravitational phenomena of different sizes and types. Geomorphological and geological field data, interpretations of remotely sensed datasets derived from ad hoc unmanned aerial vehicle (UAV) flights, and DEM-derived hillshades were also adapted to support LSQ analysis. In detail, four morphometric variables (slope, roughness, terrain ruggedness index, and elevation standard deviation) were computed and the outputs evaluated based on visual–spatial inspections of derived raster datasets, descriptive statistics, and joint comparison. Results reveal the best performing variables and how combined interpretations can support the identification and mapping of zones characterized by varying spatial distribution of gravitational landforms of different types. The findings achieved along the Mt. San Bartolo rocky coast confirm that an approach based on land-surface quantitative analysis can act as a proxy to efficiently investigate gravitational slope processes in coastal areas, especially those that are difficult to reach with traditional field surveys.
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Imaichi, Kenta, Lawrence K. Nordell, Brandt Porter und Alexander Potapov. „Development and Performance Variation of Energy Saving Type Comminution Machine Using General Purpose DEM Simulation Soft “ROCKY”“. Journal of the Society of Powder Technology, Japan 54, Nr. 10 (2017): 666–72. http://dx.doi.org/10.4164/sptj.54.666.
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Chakraborty, M., S. Panigrahy und S. Kundu. „Semi-automated Technique to Extract Boundary of Valley/mountain Glaciers using Glacio-morphological Information from Digital Elevation Model“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (28.11.2014): 511–16. http://dx.doi.org/10.5194/isprsarchives-xl-8-511-2014.
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A semi automated technique has been developed to extract the spatial extension of valleys and mountain glaciers. The method is based on morphological properties of glaciated area extracted from Digital Elevation Model (DEM). Identification of glacial boundary based on spectral information from optical remote sensing imageries produces errors due to misclassification of debris-covered ablation area with surrounding rocky terrain and perennially snow-covered slope with debris free glaciated area. Elevation information DEM of Shuttle Radar Topography Mission (SRTM), CartoDEM and ASTER DEM have been used. A part of western Himalayas was selected as the study area that contains large glaciated basins, e.g., Bhagirathi, Baspa, Chandra basin. First order derivatives, slope aspect, and second order derivatives like, profile and plan curvatures are computed from the DEM. The derivatives are used to quantify and characterise the morphological aspects of the glaciated area and used in the decision rule models to generate the glacial boundaries. The ridge lines of the study areas are also generated from the plan curvature and used in the model to delineate the catchments areas of the glaciers. The slope based boundary is checked for consistency with the boundary from profile curvature and combined manually to generate the final glacier boundary. Area and length under the derived boundary of Gangotri glacier of Bhagirathi catchments are 90.25 sq km and 30.5 km. The result has been checked with high resolution optical data. This objective approach is important to delineate glaciated area, measure the length, width and area and generate glacial hypsometry, concentration factor of the glaciers. Accuracy of the result depends up on the quality of the DEM. DEM generated by SAR interferometric technique is found superior over DEM generated from other interpolation techniques.
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Kasai, Mio, Manabu Ikeda, Toshihiro Asahina und Kazunori Fujisawa. „LiDAR-derived DEM evaluation of deep-seated landslides in a steep and rocky region of Japan“. Geomorphology 113, Nr. 1-2 (Dezember 2009): 57–69. http://dx.doi.org/10.1016/j.geomorph.2009.06.004.
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Alemayehu, Daniel, Meseret Tadesse und Mohammed Abdul Athick. „Application of TPI for Analysis of Landforms and LULC of Adama Wereda, Ethiopia“. Journal of Geographical Studies 2, Nr. 2 (08.06.2019): 100–109. http://dx.doi.org/10.21523/10.21523/gcj5.18020205.
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Topographic Position Index (TPI) algorithm is useful for landform classification using Digital Elevation Model (DEM) to identify upper, middle and lower parts of the landscape. Topographic slope positions and landform classifications can be automated and measured by employing the Jenness algorithm based on the Set of Rules in the TPI. Adama Wereda in Ethiopia has been selected to study the different landforms classified using DEM (30m resolution) and Landsat 8 OLI data. Spatial statistics and GIS applications were also used to distinguish the geomorphologic properties of DEM. Adama Wereda encompasses 2.15% of the valley, 33.79% of flat lands, 15.85 % of lower slope, 33.07% of average slope, 12.85% of upper slope and 2.24% of ridges. Nine land use and land cover (LULC) classes, specifically rocky terrain, built up area, forests, water bodies, roads, agriculture, barren land, hill/mountain and fallow land have been analyzed. Landforms of Adama Wereda are ranging from large-scale features such as plains and mountain ranges to minor features such as hills and valleys. The built-up area and agriculture are covering most of the landform classes. U shaped valley was observed in water bodies. The various classifications of TPI and landform can be used in precision agriculture, land-use alteration studies, etc.
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Tri Sutrisno, Pendi, Sigit Heru Murti und Eko Haryono. „Sidik Cepat Potensi Karst Rocky Desertification (KRD) Menggunakan Citra Landsat 8 OLI: Studi di Kawasan Karst Gunungsewu Bagian Barat“. Majalah Geografi Indonesia 34, Nr. 2 (28.09.2020): 150. http://dx.doi.org/10.22146/mgi.43013.
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Abstrak. Proses identifikasi kondisi lingkungan dapat dilakukan melalui adanya sidik cepat pemetaan Karst Rocky Desertification (KRD), termasuk di kawasan karst Gunungsewu bagian barat. Tujuan dari kajian ini adalah untuk mengetahui secara cepat potensi intensitas proses KRD yang terjadi di wilayah kajian, menggunakan metode analisis data citra penginderaan jauh multispektral. Metode yang digunakan adalah pengolahan citra secara digital menjadi citra indeks NDVI dan BI ditunjang dengan menggunakan analisis Digital Elevation Model (DEM) untuk menghasilkan data kemiringan lereng. Kriteria kelas potensi terjadinya KRD yang dihasilkan yaitu non KRD, potensi KRD rendah, potensi KRD sedang dan potensi KRD tinggi dengan luas total wilayah kajian 56.686,17 Ha. Wilayah kajian masih didominasi kelas non KRD dengan luas 32.140,56 Ha, sedangkan potensi KRD rendah seluas 24.447,72 Ha, kelas potensi KRD sedang seluas 96,53 Ha dan potensi KRD tinggi seluas 1,36 Ha. Abstract. Identification of environmental conditions can be done through the rapid mapping of karst rocky desertification (KRD) process. The purpose of this study is to know rapidly the potential of KRD processes, using Landsat 8 OLI multispectral image that covering the western part of Gunungsewu karst area. The method used is digital image processing of NDVI and BI index supported by using Digital Elevation Model (DEM) analysis to produce slope data. Criteria of KRD potential in this study are non KRD, low KRD potential, medium KRD potential and high KRD potential for total study area of 56.686,17 Ha. The study area dominated by non-KRD class with an area of 32.140,56 Ha, while the low KRD potential is 24.447,72 Ha, the medium KRD potential is 96,53 Ha and high KRD potential is 1,36 Ha.
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Dubinkin, D. M., und A. V. Yalyshev. „Determination of static loads on the body sides of a mining dump truck“. Mining Industry Journal (Gornay Promishlennost), Nr. 6/2022 (15.01.2023): 137–44. http://dx.doi.org/10.30686/1609-9192-2022-6-137-144.
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The article considers design schemes for determining static loads on the body sides of a mining dump truck. Methods for determining the static loads are described. Calculations of the pressure on the retaining wall using an analytical method were carried out. Simulation modeling of the body side loading with the method of discrete elements using the Rocky DEM software was performed. The parameters for discrete elements (with coal as the bulk material) are given. The calculated values and the previously obtained values of physical tests and studies are analyzed. Graphs and dependences of the influence of the body side height on the pressure on the retaining wall are obtained. Recommendations are given for determining the active pressure on the body side of a mining dump truck.
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Troiani, Francesco, Salvatore Martino, Gian Marco Marmoni, Marco Menichetti, Davide Torre, Giulia Iacobucci und Daniela Piacentini. „Integrated Field Surveying and Land Surface Quantitative Analysis to Assess Landslide Proneness in the Conero Promontory Rocky Coast (Italy)“. Applied Sciences 10, Nr. 14 (13.07.2020): 4793. http://dx.doi.org/10.3390/app10144793.
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Rock slopes involved in extensive landslide processes are often characterized by complex morphodynamics acting at different scales of space and time, responsible for different evolutionary scenarios. Mass Rock Creep (MRC) is a critical process for long-term geomorphological evolution of slopes and can likewise characterize actively retreating coastal cliffs where, in addition, landslides of different typologies and size superimpose in space and time to marine processes. The rocky coast at the Conero promontory (central Adriatic Sea, Italy) offers a rare opportunity for better understanding the predisposing role of the morphostructural setting on coastal slope instability on a long-time scale. In fact, the area presents several landslides of different typologies and size and state of activity, together with a wide set of landforms and structural features effective for better comprehending the evolution mechanisms of slope instability processes. Different investigation methods were implemented; in particular, traditional geomorphological and structural field surveys were combined with land surface quantitative analysis based on a Digital Elevation Model (DEM) with ground-resolution of 2 m. The results obtained demonstrate that MRC involves the entire coastal slope, which can be zoned in two distinct sectors as a function of a different morphostructural setting responsible for highly differentiated landslide processes. Therefore, at the long-time scale, two different morphodynamic styles can be depicted along the coastal slopes that correspond to specific evolutionary scenarios. The first scenario is characterized by MRC-driven, time-dependent slope processes involving the entire slope, whereas the second one includes force-driven slope processes acting at smaller space–time scales. The Conero promontory case study highlights that the relationships between slope shape and structural setting of the deforming areas are crucial for reaching critical volumes to induce generalized slope collapse as the final stage of the MRC process. The results from this study stress the importance of understanding the role of morphostructures as predisposing conditions for generalized slope failures along rocky coasts involved in MRC. The findings discussed here suggest the importance of the assessment of the slope instability at the long time scale for a better comprehension of the present-day slope dynamics and its major implications for landslide monitoring strategies and the hazard mitigation strategies.
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Kovanič, Ľudovít, Peter Blistan, Rudolf Urban, Martin Štroner, Monika Blišťanová, Karol Bartoš und Katarína Pukanská. „Analysis of the Suitability of High-Resolution DEM Obtained Using ALS and UAS (SfM) for the Identification of Changes and Monitoring the Development of Selected Geohazards in the Alpine Environment—A Case Study in High Tatras, Slovakia“. Remote Sensing 12, Nr. 23 (28.11.2020): 3901. http://dx.doi.org/10.3390/rs12233901.
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The current trend in the use of remote sensing technologies is their use as a tool for monitoring hard-to-reach areas, objects or phenomena in the alpine environment. Remote sensing technology is also effectively used to monitor geohazards and the development of human-made changes in the country. Research presented in this study demonstrates the results for the usability of the publicly available national digital elevation model DEM 5.0 obtained by utilizing the airborne laser scanning (ALS) survey to monitor the development of erosion, morphological changes of talus cones, or the dynamics of movement of rock blocks between stages of measurement in the alpine environment of the High Tatras mountains. The reference methods for this study are the terrestrial laser scanning (TLS) and structure-from-motion (SfM) photogrammetric approach using unmanned aerial systems (UASs). By comparing the created DEMs, the ALS point cloud’s accuracy on mostly rocky areas of different sizes was verified. The results show that the standard deviation of the ALS point cloud ranges from 19 to 46 mm depending on the area’s size and characteristics. The maximum difference ranges from 100 to 741 mm. The value of systematic displacement of data obtained by different technologies ranges from 1 to 29 mm. This research confirms the suitability of the ALS method with its advantages and limits for the detection of movement of rock blocks or change of position of any natural or anthropogenic objects with a size from approximately 1 m2.
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Yang, Meng, Christian Hirt, Moritz Rexer, Roland Pail und Dai Yamazaki. „The tree-canopy effect in gravity forward modelling“. Geophysical Journal International 219, Nr. 1 (07.06.2019): 271–89. http://dx.doi.org/10.1093/gji/ggz264.
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SUMMARY High resolution and accurate digital terrain models (DTMs) are frequently used as input data sets to define the topographic masses in gravity forward modelling, for example, for terrain corrections in the context of regional gravity modelling. However, over vegetated areas such as forests and scrublands, the radar- and image-based digital elevation models (DEMs) may contain a tree bias, and therefore do not represent the bare-ground surface. The presence of vegetation-induced signals in DEMs, denoted here the tree-canopy effect, will introduce errors in the gravity forward modelling. In this study, the role of the tree-canopy effect in gravity forward modelling calculations is numerically investigated. First, spectral forward modelling techniques were applied to analyse a global tree-canopy bias model with a horizontal resolution of 1 km x 1 km and to quantify its effect on global gravity forward modelling results. We demonstrate that tree-canopy signals in the DEM produce a positive bias in the topographic gravitational field over vegetated areas, with values ranging from 0 to ∼2.7 mGal for gravity disturbances. Second, the role of the tree-canopy effect in high-frequency gravity forward modelling is studied using well-known residual terrain modelling (RTM) techniques. As DEM data sets, we used the 3″ SRTM (Shuttle Radar Topography Mission Digital 9 m Elevation Database) V4.1 (containing vegetation biases) and the 3″ MERIT-DEM (Multi-Error-Removed Improved-Terrain Digital elevation model) as a representation of the bare-ground elevations. Using Tasmania and the Amazon rainforest regions as test areas with significant tree-canopy signals we show that the tree-height effect on RTM calculations is of high-frequency nature, with rather small signals which reach in extreme cases amplitudes of ∼1–2 mGal occurring at forest boundaries. Third, using ground gravity observations, validation experiments were performed over the Australian Alps, Tasmania and the Canadian Rocky Mountains. All validation experiments show that the bare-ground elevation model MERIT-DEM performs better than SRTM V4.1 in terms of reduction of the discrepancies between modelled and observed gravity values. As a general conclusion, bare-ground DEM models should be preferred in any gravity forward modelling application to avoid or reduce the tree-canopy effect.
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Li, Hongcheng, Rong Zeng, Zhiyou Niu und Junqi Zhang. „A Calibration Method for Contact Parameters of Maize Kernels Based on the Discrete Element Method“. Agriculture 12, Nr. 5 (04.05.2022): 664. http://dx.doi.org/10.3390/agriculture12050664.
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Clarifying the maize kernel movement during the crushing process is critical for improving the design and optimization of the impact mill. Rather than through experiments, maize kernel movement can be quantitatively analyzed through the discrete element method (DEM), and this could contribute more to the study of the crushing mechanism and equipment optimization. However, having an accurate particle model and contact parameters are prerequisites to ensure the accuracy of the DEM simulation. In this study, we proposed a maize kernel model construction method for the Rocky DEM simulation and a calibration method to calibrate contact parameters. The three-axis size, volume, and shape information of real maize kernels were obtained by 3D scanning, and then the maize kernel model was constructed by the section method. The particle–low-carbon-plate (p–w) and particle–particle (p–p) restitution coefficients were calibrated by using the improved inclined surface drop method. In addition, the angle of repose (AoR) and discharging time were considered together to calibrate the dynamical friction coefficients of p–w and p–p through the funnel method. Additionally, the maize kernel model and calibrated parameter values were used in a DEM simulation of the inclined surface drop test and the funnel test. The maximum relative errors between the simulation values and the measured values of the inclined surface drop test and the funnel test were 4.38% and 6.98%, respectively, which further verified that the proposed maize kernel model construction and contact parameter calibration methods are feasible and accurate. The research method used in this study is a novel idea that can be applied for the construction of the particle model and calibration of the contact parameters of granular materials with complex geometric structures, as well as the maize kernel model, and shows that calibrated contact parameters can provide a reference for the maize kernel crushing simulation to optimize the impact mill.
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McCleary, Richard J., und Marwan A. Hassan. „Predictive modeling and spatial mapping of fish distributions in small streams of the Canadian Rocky Mountain foothills“. Canadian Journal of Fisheries and Aquatic Sciences 65, Nr. 2 (01.02.2008): 319–33. http://dx.doi.org/10.1139/f07-161.
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We developed an automated procedure for modeling spatial distribution of fish occurrence using logistic regression models and geographic information system (GIS) tools. Predictors were measured from a digital elevation model (DEM) and stream layers. We evaluated the accuracy of GIS measures of reach slope through a comparison with field measures. Resource selection function models were used to explain presence-absence of bull trout (Salvelinus confluentus), rainbow trout, (Oncorhynchus mykiss), nonnative brook trout (Salvelinus fontinalis), and all fishes. Our models were extrapolated based on low, medium, and high levels of probability to produce reach-scale maps across 12 000 km2. We attempted to improve models by adding land-use variables; however, the terrain best suited to road building and harvest also contained the habitat selected by rainbow trout, whereas bull trout generally selected terrain too steep for land use. These confounding factors emphasize the need for process-based investigations in addition to correlative approaches to identify habitat requirements. This automated method provides a rapid evaluation of fish habitat across remote areas useful for salmonid conservation and research planning.
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Liu, Xianshan, und Ming Xu. „The Unsaturated Hydromechanical Coupling Model of Rock Slope Considering Rainfall Infiltration Using DDA“. Geofluids 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/1513421.
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Water flow and hydromechanical coupling process in fractured rocks is more different from that in general porous media because of heterogeneous spatial fractures and possible fracture-dominated flow; a saturated-unsaturated hydromechanical coupling model using a discontinuous deformation analysis (DDA) similar to FEM and DEM was employed to analyze water movement in saturated-unsaturated deformed rocks, in which the Van-Genuchten model differently treated the rock and fractures permeable properties to describe the constitutive relationships. The calibrating results for the dam foundation indicated the validation and feasibility of the proposed model and are also in good agreement with the calculations based on DEM still demonstrating its superiority. And then, the rainfall infiltration in a reservoir rock slope was detailedly investigated to describe the water pressure on the fault surface and inside the rocks, displacement, and stress distribution under hydromechanical coupling conditions and uncoupling conditions. It was observed that greater rainfall intensity and longer rainfall time resulted in lower stability of the rock slope, and larger difference was very obvious between the hydromechanical coupling condition and uncoupling condition, demonstrating that rainfall intensity, rainfall time, and hydromechanical coupling effect had great influence on the saturated-unsaturated water flow behavior and mechanical response of the fractured rock slopes.
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Shibaeva, Darya, Sergey Tereshchenko, Danila Asanovich und Pavel Shumilov. „On the need to classify rock mass fed to dry magnetic separation“. Записки Горного института 256 (10.11.2022): 603–12. http://dx.doi.org/10.31897/pmi.2022.79.
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The hypothesis of a possible use of dry magnetic separation is substantiated on the example of ores from ferruginous quartzite deposits operated by plants of PAO “Severstal” Holding. Size class of ore after medium crushing is –80+0 mm when the vibrating feeder is used for feeding ore mass to the separation zone. The rationale is based on the analysis of video recording of physical simulation on a laboratory drum magnetic separator of SMBS-L series, in the VSDC Video Editor, and simulation modelling of dry magnetic separation on its virtual prototype in Rocky DEM software package. It has been proved that the use of a vibrating feeder for feeding the material to the working area of a magnetic separator makes it possible to: form a monolayer on the surface of the vibrating feeder chute with a thickness close to the maximum size of a lump of separated ore; implement batch feed of material to the separation zone; increase the spacing between lumps in the separation zone when passing through the free fall area, thereby allowing dry magnetic separation of ferruginous quartzites of size class –80+0 mm without pre-preparation.
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Yu, Tian Tang, und Sheng Xu Xia. „DEM for Modeling Cracks Propagation in Rocks under Uniaxial Compression Tests“. Advanced Materials Research 433-440 (Januar 2012): 4788–93. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.4788.
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The Discrete Element Method (DEM) was used to simulate cracks propagate in rocks subjected to uniaxial compressive stress. A DEM code was developed, and used to simulate the response of the continuum materials to loading. Rock samples with two initial cracks inclined at varying angles were simulated with the DEM code. The results were compared with those obtained from laboratory samples, and it was observed that the two results were consistent. This suggests that the DEM is a robust technique for the visualization of secondary cracks formations and propagations in rocks.
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Mephors, J. O., C. O. Ogunmuyiwa, O. S. Afolabi, C. F. Agbor, O. M. Ogoliegbune und C. S. Ofordu. „Use of Digital Elevation Models to Map Out The Groundwater Resources Base Of Kuje Area to Federal Capital Territory, Abuja, Nigeria“. Journal of Applied Sciences and Environmental Management 25, Nr. 7 (22.11.2021): 1207–12. http://dx.doi.org/10.4314/jasem.v25i7.16.
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This research work examined the use of digital elevation model in the evaluation of groundwater resources in Kuje Area, Nigeria. This was achieved through the acquisition of topographic maps, Digitization of the topographic maps which were glued and interpolated to generate Digital Elevation Models (DEM) and Mapping of groundwater potential areas using ArcGIS 9.2 and ArcView 3.2a software. Findings from this research show that the study area have elevations ranging from 333 m to 429 m above sea level with a moderate groundwater potential in areas with elevation ranging from 286 m and 333 m above sea level. Some areas also have ground water problem, these areas were classified as mountainous areas and are located at very high elevations. The rocky nature of the high elevated environment makes these areas have very little hope of assessing groundwater. It was suggested that government should properly monitor groundwater, inhabitants should be made to accept laws which will help them in the conservation of ground water resources and efforts should also be made by the government towards creating incentives that will encourage people to obey these laws, Conservation methods such as retardation of surface runoff, control of vegetation and groundwater withdrawal rates should be employed.
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Adhikary, Deepak P., Marc Elmouttie, Vincent Lemiale und Brett Poulsen. „Recent advances in the stability assessment of natural and engineered rock slopes“. Journal of Nepal Geological Society 50, Nr. 1 (21.12.2016): 65–72. http://dx.doi.org/10.3126/jngs.v50i1.22866.
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Science’s understanding of the failure mechanisms of large natural and engineered slopes has been improved considerably over the past 15 years. Significant improvements have been realized in innovative methods of data acquisition through field measurement and monitoring, as well as numerical modelling techniques. However, inadequate understanding of complex geology and landslide processes means that any interpretation of landslide data remains mostly subjective. This causes major uncertainty in landslide risk assessment.
Over the past decade, Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO; http://www.csiro.au/) has developed novel techniques to facilitate efficient assessment of rock slope stability. These include SirovisionTM, Siromodel, and three CSIRO numerical codes: CSIRO‑SPH, CSIRO‑DEM and CSIRO‑COSFLOW.
SirovisionTM is a geological/geotechnical mapping and analysis system that generates accurate, scaled 3D images of rock faces from stereo photographs of exposed rock surfaces, allowing for rapid rock mass structural mapping. Siromodel is a polyhedral modelling system that reads the SirovisionTM data, generates discrete fracture networks (DFN) and performs polyhedral (rock block) modelling and a first‑pass stability analysis.
CSIRO‑SPH, CSIRO‑DEM and CSIRO‑COSFLOW are all used for detailed stress‑deformation analysis of rock slopes; however, each code has its own problem‑specific advantage. CSIRO‑SPH is suited for large deformation problems, and can simulate large scale fluid flow problems, such as modelling a dam breakage. CSIRO‑DEM is suited for rock breakage process analysis, and assessment of the runout distance of failure debris. CSIRO‑COSFLOW is designed specifically for efficient, accurate stress‑deformation analysis of stability of structures on bedded sedimentary rocks, where failures along the preexisting bedding planes and through the intact rock layers occur simultaneously.
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Calista, Monia, Francesco Mascioli, Valeria Menna, Enrico Miccadei und Tommaso Piacentini. „Recent Geomorphological Evolution and 3D Numerical Modelling of Soft Clastic Rock Cliffs in the Mid-Western Adriatic Sea (Abruzzo, Italy)“. Geosciences 9, Nr. 7 (12.07.2019): 309. http://dx.doi.org/10.3390/geosciences9070309.
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Geomorphological evolution, erosion and retreat processes that affect the rocky coasts of the mid-western Adriatic Sea (Abruzzo, Central Italy) are the subject of this research. This coastal sector, one of the few examples of clastic soft rock coasts in the Mediterranean Sea, is characterized by active, inactive and paleo cliffs, as well as coastal slopes, composed of the clayey-sandy-arenaceous-conglomeratic marine sequence (Early-Middle Pleistocene) covered by continental deposits (Late Pleistocene-Holocene). This study provides geomorphological and 3D modelling stability analyses of the cliffs of Torre Mucchia, Punta Lunga, Punta Ferruccio (Ortona, CH) and Punta Aderci (Vasto, CH), which are popular tourist sites included in natural reserve areas. They are representative of two main types of active cliffs on soft clastic rocks: cliffs on sandstone and cliffs on conglomerate with notches. In order to evaluate the processes and factors that induce cliffs to retreat and their recent evolution, the research was based on a DEM analysis (LIDAR 2 × 2 m data), aerial photos and an orthoimages interpretation, detailed geological–geomorphological surveys, and a structural analysis; field and remote investigations were combined with numerical modelling with a FLAC3D calculation code. Geological and geomorphological field data provided reliable 3D models, and FLAC3D numerical analyses allowed the definition of the most critical and/or failure areas, and the evaluation of the controlling factors, evolution mechanisms of the slopes and the sliding kinematics of gravitational instability phenomena. Different retreat mechanisms have been observed all along the investigated coastal sectors, induced by gravitational processes due to coastal erosion cycles at the foot of the cliffs, and controlled by lithological features and joints systems. The geomorphological analysis combined with the 3D modelling (i) showed that the retreat process of the cliffs is connected to translational slides and rockfalls (cliffs on sandstone), combined rockfalls, and topples (cliffs on conglomerate), largely controlled by main joints; (ii) defined the most critical areas along the cliffs. These results are of great interest in the assessment of hazard connected to potential sliding on the cliffs. Their implementation within Geographical Information Systems provides a valuable contribution to the integrated management of coastal areas, strongly improving the identification and prediction of landscape changes and supporting a new geomorphological hazards assessment, in areas of high tourism, as well as natural and cultural landscape value.
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Baliota, Georgia V., und Christos G. Athanassiou. „Evaluation of a Greek Diatomaceous Earth for Stored Product Insect Control and Techniques That Maximize Its Insecticidal Efficacy“. Applied Sciences 10, Nr. 18 (16.09.2020): 6441. http://dx.doi.org/10.3390/app10186441.
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Laboratory bioassays were conducted to evaluate the insecticidal efficacy of a diatomaceous earth deposit from Greece, for a wide range of stored product insects. In this context, populations of five different insect species, Tribolium confusum Jacquelin DuVal, the confused flour beetle; Sitophilus oryzae (L.), the rice weevil; Rhyzopertha dominica (F.), the lesser grain borer; Oryzaephilus surinamensis (L.), the sawtoothed grain beetle; Cryptolestes ferrugineus (Stephens), the rusty grain beetle, which cover a major spectrum of insects species of stored products worldwide, were used in the bioassays. The different treatment of diatomaceous earth (DE) rocks (grinding, diatomaceous enrichment, powder granulometry) led to the creation of five types of formulations (namely DE1, DE2, DE3, DE5 and DE6) that exhibited significant fluctuations in their insecticidal efficacy when applied on wheat. In general, some of the modified formulations were found to be very effective against species such as R. dominica and T. confusum that may be difficult to control at the current labeled doses of commercial DE formulations. Overall, our data clearly indicate that this specific Greek deposit has considerable insecticidal properties, which can be further utilized in designing commercial formulations for insect control at the postharvest stages of durable agricultural commodities, provided that the deposit will be modified at specific enrichment and granulometry levels.
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Liu, Xian Shan. „Research on the Discontinuous Deformation Analysis for Hydro-Mechanical Coupling Model of the Fractured Rock Masses“. Advanced Materials Research 594-597 (November 2012): 2500–2505. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2500.
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Fractured rock masses with many fractures will make the hydro-mechanical characteristics more complex. However, traditional equivalent continuous method just generally reflects the mechanical characteristics for the rocks including large fractures. In order to simulate the mechanical characteristics of the fractured rock masses under complex geotechnical environment, a new method based on Discontinuous Deformation Analysis (DDA) was forward to research on the hydro-mechanical effect. And use the method to analyze the dam foundation, the results compared with that considering non-coupling effect indicated that this model could reflect the hydro-mechanical effect in detail. In addition, FEM and DEM were applied to research on the distribution of the water head, displacement and stress under the same conditions, the results agreed with that by DDA, which further verified the feasibility of the forward method. In addition, the results about the water head and stress analyzed by DDA was greater than that by FEM and DEM, the reason was that this model simultaneously considered the normal deformation and shear deformation of the fractures. Therefore, the forward coupling method based on DDA will provide a research technique for seepage control and stability assessment of the rock engineering.
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Gimenes, Evandro, und Gabriel Fernández. „Hydromechanical analysis of flow behavior in concrete gravity dam foundations“. Canadian Geotechnical Journal 43, Nr. 3 (01.03.2006): 244–59. http://dx.doi.org/10.1139/t05-095.
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A key requirement in the evaluation of sliding stability of new and existing concrete gravity dams is the prediction of the distribution of pore pressure and shear strength in foundation joints and discontinuities. This paper presents a methodology for evaluating the hydromechanical behavior of concrete gravity dams founded on jointed rock. The methodology consisted of creating a database of observed dam behavior throughout typical cycles of reservoir filling and simulating this behavior with a distinct element method (DEM) numerical model. Once the model is validated, variations of key parameters including lithology, in situ stress, joint geometry, and joint characteristics can be incorporated in the analysis. A site-specific simulation of a typical reservoir cycle was carried out for Albigna Dam, Switzerland, founded on granitic rock, to assess the nature of the flow regime in the rock foundations and to evaluate the potential for sliding surfaces other than the damrock interface to develop. The factor of safety against sliding of various rock wedges of differing geometry present within the dam foundations was also evaluated using the DEM model and conventional analytical procedures. Estimates of crack propagation patterns and corresponding uplift pressures and factors of safety against sliding along the damrock interface obtained with the DEM were also compared with those from simplified procedures currently used in engineering practice. It was found that in a jointed rock, foundation uplift estimates after crack development obtained from present design guidelines can be too conservative and result in factors of safety that are too low and do not correspond to the observed behavior.Key words: hydromechanical, jointed rock, flow, dam design.
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Kong, Lingyun, Mehdi Ostadhassan, Siavash Zamiran, Bo Liu, Chunxiao Li und Gennaro G. Marino. „Geomechanical Upscaling Methods: Comparison and Verification via 3D Printing“. Energies 12, Nr. 3 (25.01.2019): 382. http://dx.doi.org/10.3390/en12030382.
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Understanding geomechanical properties of rocks at multiple scales is critical and relevant in various disciplines including civil, mining, petroleum and geological engineering. Several upscaling frameworks were proposed to model elastic properties of common rock types from micro to macroscale, considering the heterogeneity and anisotropy in the samples. However, direct comparison of the results from different upscaling methods remains limited, which can question their accuracy in laboratory experiments. Extreme heterogeneity of natural rocks that arises from various existing components in them adds complexity to verifying the accuracy of these upscaling methods. Therefore, experimental validation of various upscaling methods is performed by creating simple component materials, which is, in this study, examining the predicted macroscale geomechanical properties of 3D printed rocks. Nanoindentation data were first captured from 3D printed gypsum powder and binder rock fragments followed by, triaxial compression tests on similar cylindrical core plugs to acquire modulus values in micro and macroscale respectively. Mori-Tanaka (MT) scheme, Self-Consistent Scheme (SCS) method and Differential Effective Medium (DEM) theory were used to estimate Young’s modulus in macroscale based on the results of nanoindentation experiments. The comparison demonstrated that M-T and SCS methods would provide us with more comparable results than DEM method. In addition, the potential applications of 3D printed rocks were also discussed regarding rock physics and the geomechanics area in petroleum engineering and geosciences.
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Chlachula, Jiri, Nazgul Zh Zhensikbayeva, Anna V. Yegorina, Nazym K. Kabdrakhmanova, Jolanta Czerniawska und Sanat Kumarbekuly. „Territorial Assessment of the East Kazakhstan Geo/Ecotourism: Sustainable Travel Prospects in the Southern Altai Area“. Geosciences 11, Nr. 4 (01.04.2021): 156. http://dx.doi.org/10.3390/geosciences11040156.
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In spite of picturesque landscapes, natural beauties and authentic traditional lifestyles to be seen in East Kazakhstan, tourism is far from being developed. The Kazakh Altai (called the Kazakh Switzerland) is one the most colourful parts of the country and, indeed, all Central Asia. The attractiveness of this geographically isolated region (formerly a part of the Imperial Russia), consisting of rocky semi-deserts, vast parkland-steppes, and rugged mountain terrains, is reflected in its distinctive geological and geomorphological character, its pristine nature, and its extraordinary geodiversity and biodiversity. This study presents a roster of geotourism and ecotourism loci for the broader Altai area within a framework of sustainable development. The modelled assessment of the tourism and recreation potential is based upon multi-proxy analyses of GIS, DEM, and cartographic data. It integrates the most appealing natural (biotic and abiotic) site-specific natural features across all physiographic zones within a broad region. The most significant and representative geosites fall within three geographic sectors suitable for geo- and ecotourism. Prospects for travel to these places are enhanced by the presence of numerous prehistoric archaeological sites and historical monuments, which document the rich, multi-ethnic background of Kazakhstan and the ancient Silk Road that traverses it. These geological, environmental and cultural resources, and the regional geoheritage and environmental conservation concepts have been figured into strategies for economic growth of rural Kazakhstan. Visitors travelling to this most appealing region are constrained by climate of pronounced continentality, seasonality, geographic accessibility, the international border-zone regulations and a lack of services of an international standard.
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Shibaeva, D. N., B. A. Vlasov, P. A. Shumilov, S. V. Tereshchenko und V. V. Bulatov. „Application of numerical and physical modeling in designing of an X-ray luminescence separator intended for separation of ores containing luminescent minerals“. Mining Industry Journal (Gornay Promishlennost), Nr. 6/2021 (15.01.2022): 82–88. http://dx.doi.org/10.30686/1609-9192-2021-6-82-88.
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The paper demonstrates the application of numerical and physical modeling to justify the design of the X-ray fluorescence separator’s material handling system. The Rocky DEM software package is a numerical modeling tool that uses the discrete element method as a mathematical apparatus. In order to increase the efficiency of the X-ray luminescence separation, the authors suggest including an additional element in the separator’s material handling system, i.e., a drum spreader that combines a handling device and an actuating mechanism. It was found out that the best loading of the drum spreader cells, in which the number of several pieces in one cell is reduced by at least 15%, is provided by a Vibrating feeder conveyor with a triangular cross-section of the profiled part of the tray compared with the tray of parabolic cross-section. In addition, the triangular section provides a double decrease in the number of pieces with rotational movement around their axes and, accordingly, an increase of at least 5% in the average velocity of the ore flow movement along the tray. The simulation of the material handling system has shown the need to reduce the height of the end partition of the drum spreader between the cells to 45 mm, which eliminates the collision of ore pieces with the partition and subsequently, their movement in the direction of rotation of the drum spreader on its outer surface, as well as the unpredictable escape of the ore pieces beyond the working space of the separator.
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Al Raeid, Fawzi, Eugenio Di Valerio, Maria Giorgia Di Antonio, Oliva Menozzi, Mazen A. S. Abdalgader El Mziene und Clara Tamburrino. „The main issues of the Cyrene necropolis and the use of remote sensing for monitoring in the case of the eastern necropolis“. Libyan Studies 47 (November 2016): 7–30. http://dx.doi.org/10.1017/lis.2016.8.
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AbstractCyrene offers one of the largest and most spectacular necropoleis of the Mediterranean basin and, owing especially to its vastness, it is particularly difficult to control and protect. It reveals an extraordinary patrimony of rock-cut architecture, monumentally built around the ancient site, and also represents a zone at major risk of damage and destruction as a result of continuous looting, uncontrolled urbanisation and vandalism. Recent studies by Jim and Dorothy Thorn have presented a preliminary view and gazetteer of the architectonic monumentality, especially of the rocky chamber tombs, showing the need for survey projects in the area. A joint team of Libyan and Italian archaeologists, geologists, topographers and technicians of the local Department of Antiquities and Chieti University started in 1999 a project of surveying and mapping the southern and eastern parts of the necropolis, giving birth to a GIS using differential GPS and Robotic total station for the positioning and recording of the tombs, as well as multispectral HD satellite images, previously orthorectified and georeferred, combined with old maps and RADAR data for a highly detailed topographic base, up to DEM and DTM. From 2004, the survey and the GIS have been extended to the western and northern parts of the necropolis, at the moment counting more than 2,000 mapped and recorded tombs. An important step in the last two years has been the use of remote-sensing and photo-interpretation analysis in order to map the damages of urbanisation and modern construction in the areas of the necropolis. Using images covering the development of the situation every two to three months, mainly shots coming from Google Earth archives, in combination with further satellite images specifically bought for a more complete view of the last two to three years, it has been possible to start drawing a map of the areas under threat from building works and urbanisation. The aim of this paper is to present the main problems of this huge necropolis, which is at the moment one of the most threatened areas of Cyrene, every day at risk from the destruction of its monumental buildings.
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Choubey, Vishnu D., und Shailendra Chaudhari. „Geotechnical appraisal of the foundation rock mass behaviour of Narmada Sagar Dam project, central India: a case study“. Canadian Geotechnical Journal 28, Nr. 1 (01.02.1991): 148–59. http://dx.doi.org/10.1139/t91-016.
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The Narmada Sagar Dam, a concrete gravity structure under construction across the Narmada River in central India, will have a crest length of 653 m and a maximum height of 92 m. The present paper discusses the results of geotechnical investigations undertaken for evaluating the rock mass strength parameters, applying the modern concepts of rock mechanics, especially the rock mass rating, modulus of deformation, shear parameters, and strength and permeability of the dam foundation rocks. The joint systems observed are used to interpret and explain the occasional zones of poor core recovery and to explain the location and orientation of the drilling programme. It is suggested that the estimate of spacing and opening of water-conducting joints may lead to useful estimates of the groutable volume of voids in the rock mass, and inclined drill holes are preferable for optimum grouting. The values of different parameters have been obtained and correlated. The studies have led to the conclusion that the foundation rocks of Narmada Sagar Dam are competent and suitable for designing the proposed concrete gravity dam. Key words: dam, strength, elastic modulus, deformability, rock discontinuity, rock quality designation, rock mass classification.
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Muhammad, W. N., N. I. Setiawan, S. Husein und M. Nukman. „A preliminary study of geology and skarn of Cemorosewu Area, Bayat, Central Java, Indonesia“. IOP Conference Series: Earth and Environmental Science 851, Nr. 1 (01.10.2021): 012045. http://dx.doi.org/10.1088/1755-1315/851/1/012045.
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Abstract We present the first finding of skarn rocks in Cemorosewu area of East Jiwo Hill, Bayat, Central Java, Indonesia. The geological conditions of this area which related to the appearance of the skarn is also reported. The methods used in this research are DEM acquisition using drone to generate basemap for geological mapping and thin section petrographic analyses. The geological map shows that Cemorosewu area consists of metamorphic rocks (mica phyllite, graphite phyllite, with quartzite and marble lenses), sedimentary rocks (carbonate breccia and siltstone), and igneous rock (microdiorite). Based on the field observation and geological map, the regional metamorphic rocks are the oldest units in this area followed by sedimentary rocks and igneous rock which intruded both rocks. Skarn rocks were cropped out as a boulder along the Kluwihan creek with the maximum size of 8 m in length. The skarn consists of garnet, clinopyroxene, zoisite, actinolite, and minor quartz. Metasiltstone and skarn rock are suggested formed by contact metamorphism of microdiorite intrusion. The marble, which lenses within the phyllites, is suggested to be the protolith of the skarn formation in this area.
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Arkin, Eldan, Takumi Mori, Ren Himeno, Atsushi Sainoki und Akira Sato. „Analysis of the Permeability Change Resulting from Active Mineral Precipitation in Pores of Rocks by 3D-DEM“. IOP Conference Series: Earth and Environmental Science 1124, Nr. 1 (01.01.2023): 012067. http://dx.doi.org/10.1088/1755-1315/1124/1/012067.
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Abstract Carbon dioxide capture and storage (CCS) is a promising technique for reducing the concentration of CO2 in the atmosphere, and several million tons of CO2 are sequestered every year. The most important problem in CCS is ensuring aquifer safety. However, there is still room for improvement in the flow characteristics of aquifers to prevent CO2 leakage. To decrease the permeability of porous rocks, in this study, a method called ‘active mineral deposition’ was developed. In this method, some minerals are actively precipitated in aquifers, and the pores in the rock mass are closed by precipitated minerals. Because the pores are closed and stacked by minerals, the permeability of the rock mass is expected to decrease. For the precipitated minerals, CaCO3 is a promising mineral, and CaCO3 is precipitated in the pores of rocks. From microscopic observation, the approximate size of the precipitated mineral was estimated to be 10 μm in the rock pores. To verify the effect of the method, the permeability of the porous rocks was simulated using the three-dimensional discrete-element method (3D-DEM). Here, the rock minerals and pores were simulated using DEM elements, and the initial permeability of the models was estimated. Then, the small minerals, which represent precipitated minerals, were generated in the pore space, and changes in the intrinsic permeability, flow path, and pressure distributions in the rocks were estimated. The value of intrinsic permeability decreased to one tenth of the initial condition when 1% of the pore spaces were occupied by the precipitated minerals. A small amount of precipitation could change the permeability of the porous materials.
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Li, B., und Y. Jiang. „Evaluation of Failure Behavior and Strength of Fractured Rock Sample Using In Situ Triaxial Compression Tests and Expanded Distinct Element Method“. Key Engineering Materials 452-453 (November 2010): 225–28. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.225.
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The in-situ tests have been widely used to directly assess the strength and deformability of rock mass, along with which, various numerical approaches were proposed to give rational interpretations to the mechanical phenomenon happening during these tests. In this study, the so-called potential cracks are introduced into DEM model, leading to expanded DEM (EDEM) approach which is capable of simulating the cracking in intact rocks. The EDEM is applied to an in-situ triaixal compression test on a fractured rock sample. The simulation has well represented the failure mode, peak stress and elastic modulus obtained from tests as well as the cracking phenomenon and the slips on fracture planes during the loading process.
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Wang, Jian Hua. „Study on Random Reliability Analysis of Dam Abutment“. Advanced Materials Research 214 (Februar 2011): 218–23. http://dx.doi.org/10.4028/www.scientific.net/amr.214.218.
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Stability reliability analysis of abutment rock of arch dam is a very complicated problem which must be studied and solved. Generally, entirely sliding stability reliability analysis should be made when abutment rock bounded by structure planes like fault, joints and fissures, and layers is possible to slide. Due to the complex causes and structures, diverse litholigy, different rocks have different mechanics attributes. While the physical and mechanical parameters of the same rocks are of obvious dispersion and uncertainty. And it is also complex to calculate the pushing force at arch abutment on dam abutment rock, because the uncertain factors as water pressure, sediment, variable temperatures and materials parameters are contained. In this essay, based on Stochastic Finite Element Method, the formula of sliding stability reliability analysis of dam abutment rock is given. The formula can be used for entirely stability reliability analysis of dam abutment.
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Gierz, Łukasz, Łukasz Warguła, Mateusz Kukla, Krzysztof Koszela und Tomasz Szymon Zwiachel. „Computer Aided Modeling of Wood Chips Transport by Means of a Belt Conveyor with Use of Discrete Element Method“. Applied Sciences 10, Nr. 24 (18.12.2020): 9091. http://dx.doi.org/10.3390/app10249091.
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The effectiveness and precision of transporting wood chips on the transport trailer or hopper depends on an inclination angle, a conveyor belt speed, and length. In order to devise a methodology aiding designing and the selection of technical and performance parameters (aiding the settings of conveyor belt sub-assemblies), the authors carried out the simulation tests concerning wood chips transport on the belt conveyor and their outlet. For the purposes of these tests, a simulation model was performed in the Rocky DEM (discrete element method) software in the numerical analysis environment and compared to analytical tests. The tested wood chips were taken from cherry plum branches chipping processes (Prunus cerasifera Ehrh. Beitr. Naturk. 4:17. 1789 (Gartenkalender 4:189-204. 1784)), out of which seven basic fractions were separated, which differed mainly in terms of their diameter from 5 mm to 50 mm and the length of 150 mm. The article presents the results of wood chips ejection distance in the form of the 3D functions of wood chips ejection distance depending on the conveyor belt inclination angle and belt speed. The results are presented for five conveyor belt lengths (1 m, 2 m, 3 m, 4 m, 5 m). The tests also involved the conveyor belt inclination angle in the range from 10° to 50° and the belt velocity in the range from 1 m/s2 to 5 m/s2. The numerical test results demonstrate higher average values of wood chips ejection distance than designated in the analytical model. The average arithmetical difference in the results between the numerical and analytical model is at the level of 13%.
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Pachri, Hendra, Ratna Husain, Adi Tonggiroh, Muhammad Ichwanto und Regina Glori Samanta. „Study of Mineralogy and Engineering Properties of Volcanic Rock at the Base of the Pamukkulu DAM Foundation, South Sulawesi, Indonesia“. IOP Conference Series: Earth and Environmental Science 1117, Nr. 1 (01.12.2022): 012004. http://dx.doi.org/10.1088/1755-1315/1117/1/012004.
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Abstract At the location of the Pamukkulu dam, it has engineering geological characteristics that are less supportive of the construction above it, especially for the foundation of the dam. By taking data directly in the field and by laboratory testing, information is needed regarding the characterization of mineralogy and the engineering properties of rocks. Mineralogical analysis was performed with petrography and X-Ray Diffraction (XRD) while the engineering properties of the rock were performed with Plate Bearing Tests (PBT), Standard Penetration Tests (SPT), and Rock Mass Rating (RMR). Based on mineralogical data, rocks have undergone weathering and converted the chemical-physical properties of minerals into porous, fine-grained minerals, forming mineral oxides as well as clay minerals. The carrying capacity of surface soils in the dam area based on the plate bearing test is relatively poor. As for subsurface rocks, the weight of the rock mass rating belongs to the class (II) Good to (III) Medium. Meanwhile, from the density value of hard soils, there are different depths from a depth of 1 meter to 6 meters. Weathering conditions of rocks affect the engineering value of soils and rocks where due to weathering minerals formed in the form of porous clay minerals, they are not well consolidated.
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Feng, Fan, Zhiwei Xie, Tianxi Xue, Eryu Wang, Ruifeng Huang, Xuelong Li und Shixian Gao. „Application of a Combined FEM/DEM Approach for Teaching a Deep Rock Mass Mechanics Course“. Sustainability 15, Nr. 2 (04.01.2023): 937. http://dx.doi.org/10.3390/su15020937.
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Deep rock mass mechanics is a professional course which is offered to undergraduate and postgraduate students in some mining universities. This course mainly includes the following topics: the geological structure of deep rock mass, the mechanical properties of deep rocks, the strength theory of deep rock masses, stability analysis and control of deep surrounding rock classification of engineering rock masses, and the application of deep rock mechanics in underground mining engineering The purpose of this course is to present students with a basic theoretical knowledge of deep rock mass engineering. Analyzing the limitations of traditional deep rock mass mechanics teaching methods, here, we propose integrating a combined FEM/DEM (Finite Element Method/Discrete Element Method) approach into the teaching of a course on deep rock mass mechanics. The mechanical behaviors and failure instability process of rock at laboratory and engineering scales were analyzed using ELFEN software (a finite/discrete element code). The results show that a combined FEM/DEM approach as a deep rock mass mechanics teaching method is completely feasible and reasonable; this approach has the advantages of strong intuition, high reliability, time and labor savings, and low cost, which can offset the shortcomings of traditional teaching methods. Moreover, the proposed approach can stimulate students’ interests in a mining course on deep rock mass mechanics, deepen students’ understanding of the course curriculum, and cultivate students’ innovative abilities and subjective initiatives.
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Ghosh, Ranjana, und Mrinal K. Sen. „Predicting subsurface CO2 movement: From laboratory to field scale“. GEOPHYSICS 77, Nr. 3 (01.05.2012): M27—M37. http://dx.doi.org/10.1190/geo2011-0224.1.
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Finding an appropriate model for time-lapse seismic monitoring of [Formula: see text]-sequestered carbonate reservoir poses a great challenge because carbonate-rocks have varying textures and highly reactive rock-fluid system. We introduced a frequency-dependent model based on Eshelby’s inclusion and differential effective medium (DEM) theory that can account for heterogeneity in microstructure of rocks and squirt flow. We showed that the estimated velocities from the modified DEM theory match well with the laboratory measurements (ultrasonic) of velocities of carbonate rocks saturated with [Formula: see text]-rich water. The theory predicts significant decrease in saturated P- and S-wave velocities in the seismic frequency band as a consequence of porosity and permeability enhancement by the process of chemical dissolution of carbonates with the saturating fluid. The study also showed the combined effect of chemical reaction and free [Formula: see text] saturation on the elastic properties of rock. We observed that the velocity dispersion and attenuation increased from complete gas saturation to water saturation. The proposed model can be used to invert geophysical measurements to detect changes in elastic properties of a carbonate reservoir and interpret the extent of [Formula: see text] movement with time. These are the key elements to ensure that sequestration will not damage underground geologic formation and [Formula: see text] storage is secure and environmentally acceptable.
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Md. Ashikur Rahman, M. H. Sazzad und R. S. Rupom. „Geographical Information System Approach to Delineate the Watershed’s Morphometric Parameters for Sustainable Hydrological Modeling of Barind Region, Bangladesh“. MIST INTERNATIONAL JOURNAL OF SCIENCE AND TECHNOLOGY 9 (27.06.2021): 23–35. http://dx.doi.org/10.47981/j.mijst.09(01)2021.251(23-35).
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Water is an important resource of the earth’s surface and it is integral for all on this planet. The availability or the scarcity of water depends on the watershed characterizes that consider the basic, linear, and shape parameters of any waterbody. The objective of the study was to delineate 14 morphometric parameters in the Barind region (Dinajpur district, Bangladesh) for sustainable hydrological modeling. An ASTER-DEM of 30-meter resolution data, geographical information system (GIS), and Remote sensing technique were used for extracting drainage components of interest region. The whole study region was covered by the flow of the Purnovoba river, Jamuna river, Atrai river (part-1 and part-2). Research results found that the Purnovoba river had a high bifurcation ratio (0.9982) that defined hydrologically more disturbed than the other three watershed areas and it had a high stream frequency (0.8332) that denoted rocky having low infiltration capacity. Jamuna river had a low drainage density (0.7322) that defined more vegetation having higher permeability. Besides, the Jamuna river had the lowest no. of stream order that was insignificant in the steady runoff process and less prone to cause a flash flood. The research predicted that the availability of groundwater might decrease to Jamuna river in the future as it had the lowest basin area (217.42 sqr. km ) and perimeter (114.90 km) and the basin surface slope would become gentle to Atrai river part-1 for the lowest length of overland flow (0.6072). Purnovoba river experienced the lowest form factor (0.2351) which indicated the most possibility for erosion. The elongated ratio of all basins was greater than 0.5 which considered all the shapes were more elongated. These findings will help for further modeling of an integrated watershed for sustainable hydrological models in the Barind region.
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Qian, Junfeng, Yongsheng Yao, Jue Li, Hongbin Xiao und Shenping Luo. „Resilient Properties of Soil-Rock Mixture Materials: Preliminary Investigation of the Effect of Composition and Structure“. Materials 13, Nr. 7 (03.04.2020): 1658. http://dx.doi.org/10.3390/ma13071658.
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The physical composition and stress state of soil-rock mixture (SRM) materials have a crucial influence on their mechanical properties, and play a vital role in improving the performance of subgrade. To reveal the resilient behavior and mesostructure evolution of SRM materials, triaxial tests and discrete element method (DEM) numerical analysis have been carried out. In the triaxial test section, the mechanical response of SRM materials was investigated by preparing samples under different stress states and physical states and conducting triaxial tests on samples. Simultaneously, a new irregular particle modeling method was developed and applied to the discrete element modeling process to analyze the mesostructure evolution of SRM materials under cycling loading. First, a cyclic triaxial test of SRM material is performed on the SRM material, and the effects of bulk stress, octahedral shear stress and rock content on the resilient modulus of the SRM material are analyzed. It is revealed that the resilient modulus increases with increasing bulk stress and rock content, and decreases with increasing octahedral shear stress. Based on a new resilient modulus prediction model, the relationships among the rock content, stress state and resilient modulus are established. Then, based on an improved DEM modeling method, a discrete element model of the SRM is established, and the influence of rock content on coordination number and mesostructure evolution of the SRM is analyzed. The results show that in SRM materials, the increase of crushed rock changes the mesostructure of the SRM material. With the increase of rock content, the internal contact force changes from “between soil and rock” to “between rocks”, and the skeleton formed in the rocks gradually develops overall stiffness. Under the condition of low stress, the anisotropy of the SRM material is mainly caused by the shape and grade distribution of crushed rock. The induced anisotropy caused by the change of stress state has little effect on its mechanical behavior, which may lead to the greater dispersion of multiple SRM test results.
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Mao, Hai Tao, und Xiao Ju Wang. „A Study on Three-Dimensional Seepage of Dam on the Deep Pervious Fracture Rock Foundation“. Advanced Materials Research 542-543 (Juni 2012): 1061–64. http://dx.doi.org/10.4028/www.scientific.net/amr.542-543.1061.
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The theme of this paper concentrates on hydro- projects’ seepage field in rocks, including the properties of the seepage which flow through both hole qualitative like rocks and fractured rocks. Present the finite element analyzing program which can solve the problem of three dimensional seepage field in hole qualitative rock medium. Apply the program some hydro-project, computed the seepage field in the dam foundation and dam abutments. Besides, further research is done on the decision of the model range limit. And the influence of the pariah shape.
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Imrie, A. S. „Stress-induced response from both natural and construction-related processes in the deepening of the Peace River valley, B.C.“ Canadian Geotechnical Journal 28, Nr. 5 (01.10.1991): 719–28. http://dx.doi.org/10.1139/t91-086.
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The Peace River rises in the Rocky Mountain Trench and flows easterly through the Rocky Mountains before flowing onto the Plains in northeastern British Columbia near the Alberta border. Stress measurements conducted at two of three damsites near the boundary of the Foothills and the Plains reveal high remnant lateral stresses and a K0 of about 2. In proceeding 90 km downriver from the W.A.C. Bennett Dam, past the Peace Canyon Dam to the proposed site C dam near Fort St. John, the stratigraphic section changes from competent, massive sandstones of Lower Cretaceous age to soft, weak shales at the top of the Lower Cretaceous section. Valley downcutting by the Peace River through these highly stressed rocks has led to valley rebound features that have both similarities and differences where observed at each of the three damsites. Differences in rock strength at each site contribute to the variations in features noted. These valley rebound features include vertical relief joints, horizontal bedding plane joints, upward arching of the riverbed, and shear zones that both parallel and cross the bedding. The challenge for the geotechnical engineer is first to find these features and account for them in the design, as they tend to govern the foundation and slope strength even though they may only be a few millimetres in thickness. A second challenge is to appreciate that the remnant stresses that led to the formation of the features are still present and these may cause further response when excavation proceeds at a site. A geologic model for the Peace Valley is used to explain the natural and construction response to deepening of the river valley. Key words: stress measurements, damsite, remnant lateral stress, valley rebound, Lower Cretaceous shale and sandstone, relief joints, bedding plane joints, arching, shear zones, foundation design.
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Zhang, Shuai, Dongsheng Zhang, Qiang Zhao, Mingbo Chi, Wei Zhang und Wei Yu. „DEM Investigation of the Influence of Minerals on Crack Patterns and Mechanical Properties of Red Mudstone“. Processes 7, Nr. 3 (15.03.2019): 162. http://dx.doi.org/10.3390/pr7030162.
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Rocks are natural heterogeneous materials. It is common for a rock to have several kinds of minerals, which will have a significant effect on its mechanical behavior. The purpose of the numerical simulation study in this paper is to explore the effects of minerals on the crack patterns and mechanical properties of rocks. First, the corresponding calculation model is established by using the discrete element method (DEM), whereby the mechanical parameters of the blocks and joints in the Tyson polygon procedure are fitted with the rock properties obtained in the laboratory. Then, various combination models of different mineral sizes and ratios are established to study the effects of mineral size, position, and ratio on the fracture distribution and mechanical properties of rock samples. The results indicate that with increased circle size of the center mineral and the mineral ratio, the elastic modulus and uniaxial compression strength (UCS) of the model gradually increase. The drop degree of post-peak stress decreases, and the integrity and bearing capacity increase. It is found that there is a quartic polynomial relationship between elastic modulus and mineral circle radius, with R2 ≥ 0.94. The minerals located in the crack propagation path will effectively block the crack and change the propagation direction. When the mineral position is close to the model boundaries, especially the lateral boundaries, it has a significant influence on the crack initiation position, causing crack initiation to occur at the upper boundary of the mineral circle and propagate to the middle of the model. With increased mineral percentage and small-size mineral circle proportion, the depth of extension of the crack from boundary to center is reduced, the crack has wide development in the boundary area, the number of central cracks in the rock specimen decreases, and the degree of fragmentation decreases.
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Han, Tongcheng, Zhoutuo Wei und Fulai Li. „How the effective pore and grain shapes are correlated in Berea sandstones: Implications for joint elastic-electrical modeling“. GEOPHYSICS 85, Nr. 3 (01.04.2020): MR147—MR154. http://dx.doi.org/10.1190/geo2019-0756.1.
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Joint seismic-electromagnetic surveys are increasingly being used for understanding the subsurface. Valid rock-physics models are key for interpreting joint survey data. Such models should explore the cross-property relationship between the elastic and electrical properties and link the joint elastic-electrical correlations to the properties of various types of rocks of interest. However, although current differential effective medium (DEM) models have had great success in independently modeling the elastic and electrical properties of porous rock, they are not directly suitable for joint elastic-electrical modeling because the elastic and electrical DEM models describe the microstructures of the rocks in different ways. Based on dedicated laboratory measurements and theoretical modeling, we have investigated how the effective pore and grain shapes are correlated in two Berea sandstones. We determine that the effective pore aspect ratios inverted from the elastic properties exhibit a negative linear correlation with the effective grain aspect ratios obtained from the electrical inversion. The effective pore and grain aspect ratios are linked as an implicit function of varying porosity with confining pressure. Using the derived pore and grain shapes correlation, the joint elastic-electrical modeling results compared successfully with experimental data. The obtained results reveal the natural link between the effective pore and grain shapes in Berea sandstones and make the microstructures between the elastic and electrical models consistent.
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Ji, Shunying, Xiaodong Chen und Lu Liu. „Coupled DEM-SPH Method for Interaction between Dilated Polyhedral Particles and Fluid“. Mathematical Problems in Engineering 2019 (21.08.2019): 1–11. http://dx.doi.org/10.1155/2019/4987801.
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The discrete element method (DEM) and smoothed particle hydrodynamics (SPH) can be adopted to simulate the granular materials and fluid media respectively. The DEM-SPH coupling algorithm can be developed for the dynamic interaction between the two media. When the particle material is simulated by polyhedral element, a fluid-solid coupling interface would lead to the complex geometry between the granular particle and the fluid. The boundary particle method is traditionally used for the fluid-solid interface but with low computational efficiency. In this paper, the dilated polyhedral element is constructed based on Minkowski sum theory, while the contact force between the elements is calculated by Hertzian contact model. Accordingly the dilated polyhedra based DEM is established. The weakly compressible SPH is adopted to simulate the fluid medium, while the interaction on the geometrically complex fluid-solid interface is evaluated with the repulsive force model which can be determined by the contact detection between SPH particles and solid particles in geometry. This method avoids the storage and calculation of a large number of boundary particles, which can be potentially applied for the complex fluid-solid boundary. In order to improve the computational efficiency, a GPU-based parallel algorithm is employed to achieve high performance computation of SPH. The acceleration of the parallel algorithm is evaluated by the cases of dam break. The numerical simulation of the impact of dam break on cubes is implemented. The simulation results are verified with the corresponding experimental and simulation results. Therefore, the rationality and accuracy of the DEM-SPH coupling method for numerical simulation of the interaction between granular materials and fluid media are illustrated. This method is then adopted for the impact of falling rocks on underwater pipeline. The force of water and rocks on the pipeline is analyzed. This method can be further applied for real engineering problems.
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Skalski, John R., James Lady, Richard Townsend, Albert E. Giorgi, John R. Stevenson, Charles M. Peven und Robert D. McDonald. „Estimating in-river survival of migrating salmonid smolts using radiotelemetry“. Canadian Journal of Fisheries and Aquatic Sciences 58, Nr. 10 (01.10.2001): 1987–97. http://dx.doi.org/10.1139/f01-133.
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A field study to estimate the survival of outmigrating steelhead (Oncorhynchus mykiss) smolts using radiotelemetry methods is illustrated. A paired releaserecapture design was used to estimate pool (i.e., reservoir), dam, and project (i.e., reservoir plus dam) survival at two mid-Columbia River hydroprojects based on maximum likelihood estimation. The release and detection scheme was designed to minimize the possibility of detecting false-positive radio signals from smolts that might have died upstream during the hydroproject passage. Model assumptions and possible violations are discussed. Releases of radio-tagged and passive integrated transponder (PIT) tagged steelhead smolts were also compared to assess the possible effects of tag type on migration behavior. Survival through the Rocky Reach project (P = 0.86) and Rock Island project (P = 0.41) and bypass diversion probabilities at Rocky Reach Dam (P = 0.39) were found to be similar between tag types. Small but significant differences in arrival patterns (P = 0.02) and travel times (P = 0.01) were observed between radio-tagged and PIT-tagged smolts.
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Naithani, A. K., P. C. Nawani, L. G. Singh und D. S. Rawat. „Engineering geological and geotechnical investigations of dam of the Bunakha Hydroelectric Project (180 MW), Chukha Dzong, Bhutan Himalaya“. Journal of Nepal Geological Society 47, Nr. 1 (30.06.2014): 77–94. http://dx.doi.org/10.3126/jngs.v47i1.23108.
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A 197 m high roller compacted concrete gravity dam is proposed across river Wang Chhu in Chukha Dzong of the Bhutan Himalaya. Bunakha Dam will be the third highest dam constructed by India after the Tehri Dam and Bhakra Dam. The Bunakha Dam site area is located in the Thimpu Formation of the Himalayan crystalline complex. This litho-units at site is characterized by heterogeneous lithology consisting of viz. banded gneisses, foliated gneisses, with large boudins and bands of quartzite and calc-silicate gneisses with large porphyroblasts of garnet measuring up to 4 mm. These litho units form the foundation of proposed dam. In this paper attempt has been made to bring out the rock mass condition of the foundation of dam of the proposed scheme on the basis of detailed engineering geological mapping, geological logging of drill holes, rock mass permeability values, 3D mapping of exploratory drifts, geophysical profiling, in-situ and
laboratory test results. Rock mass classification using Rock Mass Rating (RMR) system and Q-system was done. The basic purpose of these investigations was to identify/map different rocks and structures like joints, shear zones, faults, fracture zones etc. and to determine engineering properties of rock and rock mass by lab
and in-situ testing and to provide basic data for economic and fail-safe design of the dam. On the basis of these investigations suitable recommendations have been made which will be helpful during the construction of the dam.