scholarly journals Limit Analysis, Numerical and Physical Modelling of Pile Stabilized Slopes

2021 ◽  
Author(s):  
Ahmadreza Mazaheri ◽  
Rasoul Alipour ◽  
Masoud Paknahad
Keyword(s):  
Numerical Modeling ◽  
Limit Analysis ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Processing System ◽  
Physical Modelling ◽  
Strength Reduction ◽  
Safety Factors ◽  
Earth Slope ◽  
Slope Safety

Abstract Vast researches have been performed in the field of earth slope stability analysis including limit equilibrium, strength reduction, and limit analysis methods. All the available methods present slope safety factors in a range with a bit of difference and confirm each other. Validation of analytical results performs with instrumentation in actual slopes existing in the field. Also, another approach that uses for validating results is experimental modeling. The physical modeling requires manufacturing of the intended model in the laboratory concerning the reducing effect of dimensions on the other parameters. This paper investigates slope safety factors against sliding by simulating the slopes in the laboratory and with an image processing system. The test container has dimensions of 1.5×1.5×2 m. The results have illustrated the crest displacement in reinforced slope, with increasing slope angle 13 degrees, is 30 mm in the experimental test and 13 mm in numerical modeling. In the unreinforced slopes, when the slope angle increased by 8 degrees, the experiment test failed, and the factor of safety in the numerical modeling is less than one.

scholarly journals Analysis of embankment slope stability: the comparison of finite element limit analysis with limit equilibrium methods

2019 ◽  
Vol 270 ◽  
pp. 02004
Author(s):  
Kongkit Yingchaloenkitkhajorn
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Limit Analysis ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Friction Angle ◽  
Volume Element ◽  
Stability Number ◽  
Limit Equilibrium Methods ◽  
Embankment Slope

This paper presented the analysis of embankment slope stability by considering the problem of embankment slope stability with special effects that it was filled with sand and was placed on purely cohesive clay. The finite element limit analysis of two-dimensional plane strain was employed to analyze the stability of this problem. The embankment slope height (H), the depth factors (d/H) and the embankment slope angle (β) for the finite element limit analysis of sand was modeled as a volume element with the properties of Mohr-Coulomb material in drained condition. And the clay was modeled as a volume element with the properties of Tresca material in undrained condition where the parameters were soil unit weight (γ), undrained shear strength (su) and friction angle (φ′). Parametric studies consisted of three dimensionless variables including depth factors (d/H), friction angle (φ′) and embankment slope angle (β). Results were summarized in the form of the dimensionless stability number (su/γH(FS)) and the design chart and application were presented. In addition, the comparison of the solution of stability number with the limit equilibrium methods and the failure mechanisms were also proposed in this paper.

Comparison of Strength Reduction Method for Slope Stability Analysis Based on ABAQUS FEM and FLAC3D FDM

2012 ◽  
Vol 170-173 ◽  
pp. 918-922 ◽  
Author(s):  
Xing Yang ◽  
Gui Yang ◽  
Ting Yu
Keyword(s):  
Numerical Calculation ◽  
Reduction Method ◽  
Characteristic Point ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Calculation Methods ◽  
Safety Factors ◽  
Evaluation Standard

Strength reduction method is widely used in the slope stability analysis. However, it is short of unified instability evaluation standard at present. And the different numerical calculation methods also influence the safety factor of strength reduction method. Taking a typical slope in this paper, the same model meshes are established in ABAQUS FEM and FLAC3D FDM by using the self-compiled model transformation program ABAQUS-FLAC3D. Then the same elastic-plastic constitutive and yield criterion are both employed in ABAQUS FEM and FLAC3D FDM. The safety factors obtained from the two numerical calculation methods are compared, and the results are also compared with that of Spencer limit equilibrium method. It is observed the safety factors calculated by ABAQUS FEM are slightly higher than that of FLAC3D FDM for the same instability evaluation standards. Moreover, the safety factors obtained from the run-through of plastic zone and the saltation of the displacement at characteristic point are much closer to that of Spencer limit equilibrium method. Hence the combination of the run-through of plastic zone and the saltation of the displacement at characteristic point as the slope instability evaluation standard is suggested in this paper. Meanwhile, the correctness of self-compiled improved strength reduction method is verified by comparing with the result of FLAC3D built-in strength reduction method.

scholarly journals A Case Study Based Slope Stability Analysis at Chittagong City, Bangladesh

2018 ◽  
Vol 3 (3) ◽  
pp. 164
Author(s):  
Atikul Haque Farazi ◽  
Abu Jafor Mia ◽  
Md. Ilias Mahmud
Keyword(s):  
Risk Mitigation ◽  
Limit Equilibrium ◽  
Probabilistic Approach ◽  
Slope Angle ◽  
Safety Margin ◽  
Landslide Hazard ◽  
Slope Length ◽  
Stability Chart ◽  
Slope Safety

Heavy rainfall occurs almost every year in Bangladesh and induces landslides in the hilly regions of this country. Among them the Chittagong City has the worst scenario―as there lives a dense population, extending from the plain lands to the hilly area. So, for risk mitigation and management in this landslide prone city, slope safety margin should be determined. From this context, this article presents factor of safety (FS) values in terms of landslide hazard at Chittagong city, based on geotechnical parameters and slope geometry. Thus a preliminary idea on the allowable stress for slope design could be made from this study. In total, 16 hazard sites of the 2007 and 2008, rainfall induced, landslides were examined as a case study along with subsequent collection of in situ soil samples of the failed slopes for geotechnical laboratory analysis. For FS calculation, the limit equilibrium method for infinite slopes was deployed along with the Cousins’ stability chart. FS values from 0.94 to 1.57 were found at the hazard sites. The results imply that FS value more than 1.57 should be used for slope safety margin. Moreover, from a probabilistic approach, the authors recommend FS > 1.80 as optimum value for the region. Furthermore, a relationship between slope height to slope length ratio, or slope angle and FS was established for this region for a quick calibration of FS value by simple on-field measurement of slope parameters. It is expected that this scenario based finding would contribute in mitigation of landslide hazard risk at the study area. Additionally, site specific FS values were presented in a map by color indexing. This research could ascertain the location wise slope strength requirement and be considered as a guideline for future calculation for slope safety design against rainfall triggered landslides in this city.

Limit Analysis of Slopes Reinforced with Multi-Directional Anchors

2014 ◽  
Vol 501-504 ◽  
pp. 27-31
Author(s):  
Ting Kai Nian ◽  
Kai Liu ◽  
Yan Jun Zhang ◽  
Dong Wang
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Strength Reduction ◽  
Reduction Technique ◽  
Upper Bound Method ◽  
Optimal Angle ◽  
Strength Reduction Technique ◽  
Parametric Studies ◽  
Earth Slope ◽  
The Stability

The upper-bound method of limit analysis combined with strength reduction technique is employed to analyze the stability of an earth slope reinforced with multi-directional anchors. A homogeneous and isotropic earth slope reinforced with two rows of anchors is considered. Attempts are made to obtain the optimal angles of anchors. Parametric studies show that, for homogeneous and isotropic slopes, the optimal angle of the first row of anchors is 0°; while the optimal angle of the second row of anchors varies with anchor positions, and generally is less than 15°.

Analysis of Unstable Rock-Mass Stability Based on Limit Equilibrium Method and Strength Reduction Method

2016 ◽  
Vol 858 ◽  
pp. 73-80
Author(s):  
Ying Kong ◽  
Hua Peng Shi ◽  
Hong Ming Yu
Keyword(s):  
Rock Mass ◽  
Failure Mode ◽  
Posterior Margin ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Rock Masses ◽  
Unstable Rock

With the slope unstable rock masses of a stope in Longsi mine, Jiaozuo City, China as the target, we computed and analyzed the stability of unstable rock masses using a limit equilibrium method (LEM) and a discrete element strength reduction method (SRM). Results show that the unstable rock masses are currently stable. Under the external actions of natural weathering, rainfall and earthquake, unstable rock mass 1 was manifested as a shear slip failure mode, and its stability was controlled jointly by bedding-plane and posterior-margin steep inclined joints. In comparison, unstable rock mass 2 was manifested as a tensile-crack toppling failure mode, and its stability was controlled by the perforation of posterior-margin joints. From the results of the 2 methods we find the safety factor determined from SRM is larger, but not significantly, than that from LEM, and SRM can simulate the progressive failure process of unstable rock masses. SRM also provides information about forces and deformation (e.g. stress-strain, and displacement) and more efficiently visualizes the parts at the slope that are susceptible to instability, suggesting SRM can be used as a supplementation of LEM.

Numerical Simulation Method Ascertaining Slope Stabilization Anti-Slippery Pile's Basic Parameters

2012 ◽  
Vol 594-597 ◽  
pp. 222-225
Author(s):  
Wen Juan Feng ◽  
Xiao Dong Ju ◽  
Zheng Sheng Zou
Keyword(s):  
Numerical Simulation ◽  
Safety Factor ◽  
Limit Equilibrium ◽  
Simulation Method ◽  
Simulation Software ◽  
Strength Reduction ◽  
Slope Stabilization ◽  
Limit Equilibrium Methods ◽  
Basic Parameters ◽  
Shear Strength Reduction

Although anti-slide pile take a key position in slope-treating measures, the method of designing is far from perfect. The methods used in actual projects are based on the rigid body limit equilibrium methods. There is a tendency to using numerical methods in the progress of pile-designing. The safety factor of landslide is calculated according to shear strength reduction theory in the numerical simulation software. Using the shearing forces on pile and the safety factor can ascertain the position of anti-slide piles, the area and distance of piles. For numerical simulation can well perform the simulation slope moving and the load on piles and can give a more reasonable designing.

scholarly journals Application of Harmony Search Algorithm to Slope Stability Analysis

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1250
Author(s):  
Sina Shaffiee Haghshenas ◽  
Sami Shaffiee Haghshenas ◽  
Zong Woo Geem ◽  
Tae-Hyung Kim ◽  
Reza Mikaeil ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Search Algorithm ◽  
Limit Equilibrium ◽  
Harmony Search ◽  
Harmony Search Algorithm ◽  
Slope Stability Analysis ◽  
Unit Weight ◽  
Slope Safety

Slope stability analysis is undoubtedly one of the most complex problems in geotechnical engineering and its study plays a paramount role in mitigating the risk associated with the occurrence of a landslide. This problem is commonly tackled by using limit equilibrium methods or advanced numerical techniques to assess the slope safety factor or, sometimes, even the displacement field of the slope. In this study, as an alternative approach, an attempt to assess the stability condition of homogeneous slopes was made using a machine learning (ML) technique. Specifically, a meta-heuristic algorithm (Harmony Search (HS) algorithm) and K-means algorithm were employed to perform a clustering analysis by considering two different classes, depending on whether a slope was unstable or stable. To achieve the purpose of this study, a database made up of 19 case studies with 6 model inputs including unit weight, intercept cohesion, angle of shearing resistance, slope angle, slope height and pore pressure ratio and one output (i.e., the slope safety factor) was established. Referring to this database, 17 out of 19 slopes were categorized correctly. Moreover, the obtained results showed that, referring to the considered database, the intercept cohesion was the most significant parameter in defining the class of each slope, whereas the unit weight had the smallest influence. Finally, the obtained results showed that the Harmony Search algorithm is an efficient approach for training K-means algorithms.

Analysis of Slope Instability Based on Strength Reduction Method

2012 ◽  
Vol 170-173 ◽  
pp. 1238-1242
Author(s):  
Xue Wei Li ◽  
Xin Yuan ◽  
Xiao Wei Li
Keyword(s):  
Plastic Zone ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Strength Reduction ◽  
Slope Instability ◽  
Strength Reduction Method ◽  
Numerical Convergence ◽  
Safety Coefficient ◽  
Reduction Coefficient ◽  
Slope Factor

Abstract. Combined the strength reduction method with ABAQUS, the development of the slope plastic strain of different reduction coefficient is obtained by constantly adjusting reduction coefficient to change the strength index of the soil. The reduction coefficient is obtained from the criterion of numerical convergence and displacement mutation and plastic zone breakthrough. Through the analysis and comparison with the results, the reduction coefficient by the criterion of displacement mutation is consistent with the result of the criterion of plastic zone breakthrough. The reduction coefficient is the safety coefficient of the slope, and compared and analyzed with the slope factor of limit equilibrium method Bishop. The result shows that the displacement mutation and the plastic zone breakthrough as criterions to judge the slope instability are reasonable.

Pseudo-Static Analysis of Slope Considering Circular Rupture Surface

2014 ◽  
Vol 5 (2) ◽  
pp. 37-43 ◽  
Author(s):  
Sima Ghosh
Keyword(s):  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Failure Surface ◽  
Friction Angle ◽  
Equilibrium Analysis ◽  
Seismic Slope Stability ◽  
Slide Mass ◽  
Critical Circle ◽  
Seismic Forces

In this present paper, a circular failure surface passing through the toe is assumed for a homogeneous soil, and the Fellenius line is used to locate the centre of the most critical circle. Using limit equilibrium analysis under the influence of static forces such as weight of potential slide mass and surcharge along with the pseudo-static seismic forces are considered to obtain the factor of safety of the slopes. Factor of safety is found through the application of force equilibrium. The effects of variation of different parameters like slope angle (i), soil friction angle (F) and seismic acceleration coefficients both in the horizontal and vertical directions (kh and kv respectively) on the factor of safety are presented. Finally, the present results are compared to the existing solutions available in literature and found to give minimum values of factor of safety using the present approach for seismic slope stability analysis.

scholarly journals Dynamic Stability Discrimination Method for Concrete Dam under Complex Geological Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Liaojun Zhang ◽  
Tianxiao Ma ◽  
Hanyun Zhang ◽  
Dongsheng Chen
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Limit Equilibrium ◽  
Element Model ◽  
Safety Factors ◽  
Stability Calculation ◽  
Dam Foundation ◽  
Geological Conditions ◽  
Dam Foundations

The instability of dams will bring immeasurable personal and property losses to the downstream, so it has always been a trendy topic worthy of investigation. Currently, the rigid body limit equilibrium method is the most commonly used method for the dynamic stability analysis of dams. However, under the action of earthquakes, the instability of the integral dam-foundation system threatens the safety of the dams and is of great concern. In this paper, a stability analysis method that can reflect the complex geological structural forms of dam foundations is proposed in this paper. The advantages are that this method deals with the difficulty in assuming sliding surfaces and the lack of quantitative criteria for the dynamic instability analysis of dams with complex geological structural forms of dam foundations. In addition, through the method, the sliding channels that may appear in the dam foundations can be automatically searched under random earthquake action, and the safety factors of the dynamic instability of dams be quantitatively obtained. Taking a high RCC gravity dam under construction in China as an example, the proposed method is applied to the three-dimensional finite element model of the dam-foundation system of this dam, and then the dynamic stability calculation is carried out. Through this method, the formation process of the dam foundation’s plastic zone and the failure of sliding channels with different strength reduction coefficients are studied on and analyzed detailedly, and the quantitative acquisition of the safety factors is realized. The results show that the method is reasonable and feasible, and helps provide a new idea and method for the dynamic stability analysis of dams.

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