Slope Stability Analysis Method Research Articles

Stability Analysis Method for a Prestressed Railway Embankment considering the Additional Stresses Propagation Effect

Abstract To evaluate the stability of a prestressed railway embankment (PRE), approximate solutions for the additional normal and shear stresses on an arbitrary potential sliding surface of a PRE are first derived using the elastic theory, by which the propagation effect of additional stresses due to the prestressing loads is appropriately considered. Then, a limit equilibrium slice method incorporating the additional stress effect, equivalent interslice forces, track weight, and train axle load but avoiding repeated iteration calculations is developed to analyze the PRE stability. The additional stress solutions are also introduced to modify three commonly used conventional slope stability analysis methods, and comparative analyses were performed to investigate the applicability of the proposed method. The results showed that the differences between the safety factor (Fs) of a PRE evaluated using the proposed and modified methods were within 2% in this study and the values were less than those yielded by the conventional methods because of the partial negative effect of the additional normal and shear stresses on a few slices around the lateral pressure plate (LPP). Besides, the adaptive genetic algorithm was introduced to search the critical sliding surface of the PRE. Finally, the effect of reinforcement pressure on the stability of a PRE was investigated, where the results indicated that the Fs of the PRE increased from 1.323 to 1.626 with an increase of the reinforcement pressure from 0 to 200 kPa, while the PRE gradually varies from potential integral instability to potential local instability. The accurate and efficient determination of the additional stresses on the sliding surface is important in analyzing the PRE stability, and the developed method can provide an easy-to-use and relatively safer stability analysis method for the design of a PRE.

The Use of Innovative Techniques for Management of High-Risk Coastal Areas, Mitigation of Earthquake-Triggered Landslide Risk and Responsible Coastal Development

Coastal areas constitute a very dynamic environment, balancing between numerous natural and anthropogenic processes liable to sometimes hazardous geomorphic phenomena. Especially in tectonically active coastal regions and areas of high economic value, slope failures can have significant impacts and therefore need careful and detailed examination. This work uses Unmanned Aerial System (UAS)-aided photogrammetry and Terrestrial Laser Scanning (TLS) in tectonically active segments of the coastal zone of the Ionian Islands in Greece, to explore how their capabilities can help to improve our understanding of the structural integrity of the slopes. Results show that the two approaches are able to extract large numbers of discontinuity facets, in a more practical, rapid and safe way than conventional methods of rock slope stability analysis extending to unreachable yet important parts of the slope. Through this holistic record of the structural condition of the slope the two applications allow the identification of segments that are more prone to instability and failure. In this way, they improve our understanding of the prioritization of interventions aiming to enhance the prevention of slope failures, mitigating the associated risk and improving local development in these high-value locations.

DEVELOPMENT OF A SIMPLE DESIGN CHART AS AN EVALUATION OF SLOPE STABILITY

Landslides can damage public facilities and also have a negative impact on the community. This impact will be able to minimize when knowing the slope stability by carrying out the analysis to determine the factor of safety against landslide. The most accurate results usually get from calculation through computer software, but sometime it will take time and also not all of the designer have the sophisticated software. Another method in predicting the slope stability is using design chart as carried out in this study. The aim of this study is as a sustainable development of a simple chart to help the designer in predicting the landslide possibility. The graph will consist of the relationship between the slope height and the factor of safety for several soil strength parameter and slope angles. The slope stability analysis method will be based on LEM (Limit Equilibrium Method) through Bishop’s equation. The result is then being tested through case study and comparing with the other existing design chart and show a satisfactory result.

Key group analysis based on DDA method for rock slope stability analysis

Inhomogeneity and discontinuities play a key role in resistance and behavior of rock masses. Today engineers have a wide range of methods to analyze the stability of rock slopes. Due to its simplicity and speed of evaluation, static analysis methods continue to play a special role in the stability assessment of jointed rock slopes. One of the most well-known static methods used in the stability analysis of rock slopes is the Key Block method (KBM), which is based on the key block finding and analyzing. In this method, if none of the key blocks are unstable, it implies that rock mass is stable. Occasionally, the combination of a number of stable blocks has led to formation a group of blocks that sometimes leads to instability. Therefore, the stability analysis of the jointed rock masses leads to study of groups of blocks that are potentially dangerous for the stability of a rock slope. The Key Group method (KGM), with its progressive approach, finds these critical groups and focuses the stability calculations on these groups. In order to increase the efficiency, accuracy and speed of this method and to develop it in three dimensions, it is decided to combine it with one of the numerical methods. The standard Discontinuous Deformation Analysis method (DDA) is an implicit method based on the finite element method. This is a sophisticated numerical method for modeling the quasi-static and dynamic behavior of rock block systems in discontinuous rock masses. The goal of this paper is to use of the potency of the numerical method of DDA to analyze the candidate key group. For this purpose, the DDA computer program was developed with Mathematica programming language and combined with the KGM software. The resulting package, after selecting the key group by the KGM method, proceeds to analyze it with the DDA method. Two examples solved illustrating the reasonable results and the efficiency of this developed method compared to that of the original KGM and SKGM. The results validated the proper accuracy and good performance of the procedure developed in this research.

Geotechnical Perspective on Dozer-Push Method in Coal Mining Operations

The rapid increase of technological development is currently playing a role in the mining industry. The dozer push exploitation method is an alternative to the conventional truck and shovel method. Heavy dozers have the ability to move large amounts of waste material in short distances at a low cost, while trucks and shovels will be more economical if over long distances. Geotechnical assessment becomes one of the critical considerations in making a decision plan and slope design for mining activities where the dozer push activities were carried out. Material conditions greatly affect slope stability, which can be defined as material behavior based on the physical and mechanical properties of the material. The slope stability analysis method used in this study was a combination of two methods, the Limit Equilibrium Method (LEM) and Finite Element Method (FEM). These two combinations of analytical methods will strengthen the justification of the geotechnical perspective. By understanding the behavior of the material on a slope, the risk of a slope failure can be controlled and minimized using a geotechnical perspective. The parameters that will be studied in this study are the physical and mechanical properties of the material against several conceptual design options

Development of the scaled boundary finite element method for image-based slope stability analysis

This paper presents a numerical technique for geotechnical slope stability analysis, integrating digital image meshing with the scaled boundary finite element method, allowing site conditions such as complex stratigraphies, surface and internal geometry evolution to be simulated in a robust and straightforward procedure. The quadtree decomposition technique is used to automatically discretise the geometry directly from digital images using pixel information to accurately capture boundaries with fine-scale elements. The process allows complex numerical models to be generated from cross-section images of slopes, capitalising on the combination of the scaled boundary finite element method and quadtree meshing. The spatial distribution of the soil material properties can be represented by the colour of each pixel. A mapping technique is developed to integrate these parameters into the computational mesh. The feasibility of the proposed method is presented through case study simulations of an active large Australian open-pit mine, considering various aspects of complex features such as geometry, stratigraphy and material behaviour.

SLOPE STABILITY ASSESSMENT OF THE UPSTREAM SLOPE OF THE DRY MOUNTAIN FLOOD CONTROL RESERVOIR DURING THE FLOOD

The flood control is one of the priority goal for successful economic activity on the areas that are periodically suffer from floods. Such areas are the mountainous regions of the Ukrainian Carpathian Mountains. Floods on the mountain rivers are repeated several times each year, and are characterized by the sudden water level rise with almost the same rapid decrease of the water level. Active flood protection measures include dry mountain flood control reservoirs, the principle of which is to transform part of the flood runoff and to accumulate water for the short time in the the artificial reservoir, with followed rapid emptying to the minimum level. The complex hydraulic regime is formed in the body of the dam which forms the flood control reservoir during the flood, that is different from the operation of the water permanent reservoir. The design of the flood control structures is car-ried out in accordance with Ukrainian building codes for the construction of the water reservoirs with constant water level, and require testing the stability of the downstream slope for the maximum water levels under steady state seepage conditions and assessment the upstream slope stability during the water level decreasing from the maximum level calculated in the steady state condition, these calculations do not correspond to the real seepage processes in the body of the dam of the dry flood control reservoir. Therefore, the purpose of this work is to determine the necessary boundary conditions of the flood control reservoir operation and upstream slope stability assessment by the limit equilibrium method. In the article the operation of the dry mountain flood control reservoir was analysed and found that the dam was characterized by two states: dry reservoir with water minimum water level and variable position of the seepage curve in the core and the upstream prism during the flood. The main factors influencing the upstream slope stability are the physical and mechanical properties of the soil, the laying of the slope, the period of time when the high-water level is maintained and the intensity of water level dropping. The upstream slope stability was evaluated by the Morgenstern & Price and Ordinary methods on the Slope/w software package. After the first 25 hours of the flood (period of high-water levels and the next water level dropping) the Safety Factor evaluated by limit equilibrium methods began to decrease, and reached the minimum value during the greatest seepage curve gradients at the time between 45 and 50 hours. Slope stability calculations by the limit equilibrium method were compared with the results of calculations performed by the SRM method, the values ​​of the Safety Factor and the way of their change during the flood evaluated by Ordinary and SRM methods almost coincide, which indicates the reliability of the results obtained by different methods of slope stability analysis

Theoretical studies and applications of an upper-bound stability analysis method based on the failure mode of inclined slices

This paper provides an in-depth study of the upper-bound slope stability analysis method proposed by Donald and Chen using inclined slices to simulate the sliding mass (Energy Method Upper-bound, abbreviated to EMU). After a brief review of the theoretical background and numerical method of the EMU, the authors present a weightless slope subjected to a vertical ultimate load to demonstrate its theoretical background. It has been proven that the analytical formulation of the EMU is identical to the closed-form solution given by the slip line method (SLM) for this selected example. Conversely, using its computer program, EMU has produced several closed-form solutions selected from Sokolovski. Thus, the potential for applications in practical engineering problems is demonstrated. With its theoretical background and numerical feasibility, EMU is extended to the area of bearing capacity of strip footings whose theoretical background is based on the slip line theory by Prandtl but involves various semi-empirical factors accounting for the effect of the soil weight, inclined and eccentric loading, and multi-layer foundations. This paper presents a preliminary investigation of semi-empirical approaches to the factors accounting for soil weight. Alternatively, the authors present a computer program Bearing-IWHR at the web, which is an Excel/VBA coded spreadsheet to perform numerical bearing analysis without the need for the semi-empirical factors.

Retraction Note: Reliability of variable slope system and human motion image detection based on Markov chain

With the continuous development of computer networks and the continuous popularization of computer network technology, image detection technology has gained a lot of room for development with the help of the development of image processing technology, and has also been greatly improved in a period of development. When people carry out geotechnical engineering construction, the stability of the slope is related to the safety and construction effect of the entire project. In the specific operation process, researchers usually use appropriate calculation methods to calculate various parameters in engineering construction, and use calculations to specifically determine the stability of highway slopes. In order to improve the safety of geotechnical engineering construction and the stability of highway slopes, this article selects the parameters involved in the slope stability analysis method for analysis, and establishes an equation for reliability analysis during the analysis. By comparing the analysis results of other methods, the researchers believe that the limit equation set in this article can improve the reliability of slope stability analysis. This article also designs a method of human motion image detection, which specifically studies the human motion posture, and uses the characteristics of the skeleton point image and the Euclidean distance to accurately recognize the human motion.

SOIL SLOPE STRESS STATE AND STABILITY ANALYSIS BASED ON UNLOADING EFFECT OF SLOPE SURFACES

In the limit equilibrium method for slope stability analysis, it is difficult to consider the stress state of the soil and the calculation of slope sliding surface stress has relied on the finite element numerical method for a long time. To solve this problem, the idea of slope surface unloading and equivalent stress is proposed. After considering the slope surface as a semi-infinite boundary, the slope stress is solved by the elastic theory. Then the stability safety factor is calculated according to the slip surface stress. Finally, the position of the potential sliding surface, the stress distribution of the sliding surface and the safety factor are compared with the existing theories based on the several example. The research results show that the concept of slope surface unloading and equivalent stress is clear and conforms to the slope force characteristics. The sliding surface stress obtained by this method is basically consistent with the finite element calculation results. The searched potential sliding surface position and the corresponding stability safety factor are very close to the finite element strength reduction method and the limit equilibrium method calculation results. In addition, the calculation method can be effectively combined with prestressed support structures, reflecting the reinforcing effect of prestressing.

Influence of Layer Transition Zone on Rainfall-Induced Instability of Multilayered Slope

Abstract Although numerous studies have been paid much attention to rainfall-induced instability of multilayered slopes, the interface between layers is generally considered to be “zero thickness”, and the layer transition zone between layers is neglected. In this study, the influence of the layer transition zone on the rainfall-induced instability of multilayered slope was investigated. A model was developed to simulate the rainfall infiltration process, the distribution of pore water pressure, and the stability of multilayered slope by coupling the unsaturated seepage model and the slope stability analysis method. Based on the analysis of the multilayered slopes with the different thickness ratios of the layer transition zone, a method for determining the critical thickness of the layer transition zone was proposed. The results showed that the layer transition zone had a significant influence on the stability of multilayered slope. It was found that the presence of the layer transition zone in the multilayered slope reduced the hydraulic conductivity of the slope and increased the rate of formation of transient saturated zone, which contributed to excess pore water pressure at the toe of the slope. The analysis of the local factor of safety (LFS) showed that when the thickness ratios of the layer transition zone were between 2.5% and 5%, the corresponding hydraulic conductivity of the slope decreased by 1%-2.5% and the maximum failure area of the slope during the rainfall was 25% of the slope. Our study highlighted the importance of the layer transition zone for the rainfall-induced instability of the multilayered slope.

The effect of maximum iteration using 3 dimensional limit equilibrium method in open pit mine

Nickel ore mines have a high potential of landslides due to their weak material base, which consists of soil. It is caused by the increase of soil density in rain conditions, leading to decreased soil shear strength (c) and internal friction angle (ϕ). This research aims to determine the optimum value of the maximum iteration number based on the Cuckoo Search and Particle Swarm Optimization search method. In this research, the slope is analyzed using the 3 Dimensional limit equilibrium method “Simplified Bishop,” a slope stability analysis method that uses the principle of static equilibrium. Alongside this method, the Cuckoo Search and Particle Swarm Optimization is adopted. The Cuckoo Search and Particle Swarm Optimization are metaheuristic optimization techniques used as the slipped surface search method. Series of 3-dimensional limit equilibrium computation is performed using different amounts of nests in the cuckoo search method and different particle values and maximum iteration number. Cuckoo Search method to achieve optimal nest 100 and iteration of 80 with the fastest compute time of 3 minutes 49 seconds. While the Particle Swarm Optimization to achieve optimal on particles 60, iteration as much as 480 with a compute time of 6 minutes 46 second, with a factor of safety value of 1,12.

Slope stability analysis via Discrete Element Method and Monte Carlo Simulations

It is difficult to consider the heterogeneity and discontinuity of rock and soil in conventional slope stability analysis. This paper proposes an efficient slope stability analysis method based on discrete element method (DEM) and Monte Carlo simulations(MCS). The analysis employed the stacking models with multiple slopes and the element displacement to achieve rapid analysis of slope stability. Using on the high-performance discrete element software MatDEM, a stacking model containing 100 2D slopes and a total of more than 800,000 elements was generated. The element tensile strength F and friction coefficient μ p were set as random variables to consider the material heterogeneity and uncertainty. We performed the stability analyses of 40,000 slopes for 28 hours. The numerical results show that the slopes were instable when a sudden displacement and penetrating sliding surface occurred. The coefficient of variation COVPf of slope failure probability is greatly meets the target accuracy requirements of MCS, which shows the method can be applied to the refined analysis of slopes with high-precision requirements and multiple random variables.

Development of empirical correlations for limit equilibrium methods of slope stability analysis

Development of empirical correlations for limit equilibrium methods of slope stability analysis

Subsidence Monitoring Base on SBAS-InSAR and Slope Stability Analysis Method for Damage Analysis in Mountainous Mining Subsidence Regions

Surface subsidence caused by coal mining has a great impact on the geological and ecological environments and causes damage to houses, roads, and industrial buildings. In order to understand the subsidence pattern in the mountainous mining regions, three mining faces of the Zhangjiamao mining area in the north of Shaanxi province, northwestern China are taken as case study. Firstly, the small baseline subset (SBAS) technology is used to process 12 images obtained in the mining area to investigate the subsidence data from December 2019 to April 2020. The boundary of surface deformation of the mining area interpreted by the SBAS-InSAR technology is inconsistent with the theoretical boundary suggested by coal mine subsidence theories. Especially, there are some areas in which the real subsidence are larger than estimated area. This discrepancy must be corrected as steep slopes near the theoretical boundary may increase the likelihood of landslides. Our research indicates that: (1) The accumulated displacement and the maximum deformation rate reached −120.759 mm and −270.012 mm/yr in the study area, and the subsidence boundary of the three mining faces is revealed; (2) the combination of the predicted boundary and slope stability analysis can effectively identify the landslide region at the edge of subsidence boundary; (3) the field surveys have proved the effectiveness of this method. The mining area subsidence revealed by our research helps to further understand the impact of land subsidence caused by mining in the mountainous areas and provides a practical method to predict subsidence boundaries and the likelihood for landslides.

INTEGRATED SLOPE STABILITY ANALYSIS (SSA) WITH TRANSIENT GROUNDWATER FINITE ELEMENT METHOD FOR EMBANKMENT ANALYSIS

The content of level has a big enough role in the value of the physical characteristic and the mechanical of material. The behavior of water in these materials needs to be analyzed first in order to support the slope stability analysis. Modeling of water behavior in materials in the construction of Tailing Storage Facilities (TSF) will be integrated in the slope stability analysis. This study aims to provide an explanation about the analysis of the Fishing Storage Facilities (TSF) which integrates transient groundwater analysis using the finite element method in supporting the stability analysis of the embankment of Tailing Storage Facilities (TSF). The variables that are used in the analysis, they are the parameters of physical properties and mechanic material for embankment and permeability parameters in analyzing groundwater. The analysis method for geotechnical and geohydrology modeling uses the finite element method. The results of analysis showed that groundwater behavior in the embankment material can be known in detail so that it can be integrated with stability analysis. It can be seen that there is a decrease in the value of the slope safety factor using the Integrated Slope Stability Analysis method compared to the conventional method. Adding an impermeable layer using a thickness of 5 m of clay material and a thickness of 20-30 m to support the retaining wall/foot is the criterion of optimal stability. The required lining material thickness (D) can be expressed by the following drawdown percentage equation function: reduction percentage = (1-0.8661D (-0.031)) * 100%.

Estimation of landslide prone zones around the Semarang Fault based on by combining the slope stability analysis and HVSR microtremor methods

Morphologically the City of Semarang consists of Downtown and Uptown Semarang. Downtown Semarang which is composed of alluvial deposits and sandstone of the Damar Formation. Uptown Semarang composed of conglomerate of the Damar Formation, claystone of the Kalibiuk Formation, volcanic breccia of the Kaligetas Formation, volcanic breccia of Ungaran Volcano, Andesite igneous rock, and Basalt igneous rocks. Upper Semarang is hilly, some of which have steep slopes, especially on the Semarang Fault Zone. This condition makes the area frequent landslides. To find out the zone that is prone to landslides in the area around the Semarang Fault, slope stability analysis and microtremor measurements were performed. Slope stability analysis was carried out at 7 points using the bishop method based on slope, specific gravity, internal shear angle and soil cohesion. The acquisition by microtremor method was carried out at 9 trajectories that were estimated to pass through the Semarang Fault, then from the Horizontal to Vertival Spectral Ratio (HVSR) curves obtained was carried out an inversion to obtain the shear wave velocity profile on the trajectory. From the two methods of analysis found several locations with potential landslides, namely in the area of Mangun Harjo in the east of the study area, Karangrejo in the middle of the study area and Sadeng in the west of the study area.

Evaluation of Deep Learning against Conventional Limit Equilibrium Methods for Slope Stability Analysis

This paper presents a comparison study between methods of deep learning as a new category of slope stability analysis, built upon the recent advances in artificial intelligence and conventional limit equilibrium analysis methods. For this purpose, computer code was developed to calculate the factor of safety (FS) using four limit equilibrium methods: Bishop’s simplified method, the Fellenius method, Janbu’s simplified method, and Janbu’s corrected method. The code was verified against Slide2 in RocScience. Subsequently, the average FS values were used to approximate the “true” FS of the slopes for labeling the images for deep learning. Using this code, a comprehensive dataset of slope images with wide ranges of geometries and soil properties was created. The average FS values were used to label the images for implementing two deep learning models: a multiclass classification and a regression model. After training, the deep learning models were used to predict the FS of an independent set of slope images. Finally, the performance of the models was compared to that of the conventional methods. This study found that deep learning methods can reach accuracies as high as 99.71% while improving computational efficiency by more than 18 times compared with conventional methods.

Finite Element Analysis Method of Slope Stability based on Fuzzy Statistics

In order to reduce the risk of slope stability evaluation due to the fuzziness of calculation parameters, a finite element analysis method of slope stability based on fuzzy statistics is proposed. Based on the principle of quasi-static method and with the help of the finite element software COMSOL multiphysics, this paper studies the stability of the gravel soil accumulation rock slope under the action of different seismic acceleration. By analyzing the displacement, plastic zone and safety factor of the rock soil slope, the stability of the rock soil slope is analyzed. The research results show that the fuzziness of mechanical parameters of rock and soil slope will lead to the fuzziness of position displacement and stress analysis results of rock and soil slope, and the analysis of rock and soil slope with the method of fuzzy finite element analysis can strengthen the comprehensive understanding of position displacement, stress and safety of rock and soil slope by engineers and technicians, and reduce the stability of rock and soil slope due to the fuzziness of calculation parameters to a certain extent Evaluate the risk qualitatively.

Application of Flow Velocity and Direction Measurement System in Slope Stability Analysis

Hydrodynamic pressure is often a crucial factor in the evaluation of slope stability analysis, especially for many rainfall-triggered landslides. Nevertheless, hydrodynamic pressure is rarely considered in the traditional limit equilibrium slice method of slope stability analysis since effective and reliable hydrodynamic pressure data are often lacking in practice. Moreover, efficient methods to involve these data in slope stability analysis are an urgent need. To overcome these concerns, the flow velocity and direction system (FVDS) is employed to measure the groundwater flow velocity, which can be used to generate hydrodynamic pressure samples at different monitoring points. Based on these samples, the hydrodynamic pressure of each soil strip is estimated using artificial neural networks (ANNs). Afterward, an improved Bishop method that considers hydrodynamic pressure is proposed. The effectiveness and significance of the proposed method are illustrated with a case study, the Fanshantou landslide in Zhejiang Province, China. The safety factor before and after taking drainage countermeasures is also calculated and compared. The results indicate that hydrodynamic pressure plays an important role in the stability analysis of the Fanshantou landslide. Compared with the classical Bishop method, the improved method is shown to agree better with the actual deformation characteristics of the landslide.