scholarly journals Laboratory and 3-D distinct element analysis of the failure mechanism of a slope under external surcharge

2015 ◽  
Vol 15 (1) ◽  
pp. 35-43 ◽  
Author(s):  
N. Li ◽  
Y. M. Cheng
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Slip Surface ◽  
Distinct Element ◽  
Failure Mechanisms ◽  
Laboratory Model ◽  
Element Analysis ◽  
Additional Information ◽  
Major Disaster ◽  
Failure Conditions

Abstract. Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient detail. There is however increasing interest in the consequences after the initiation of failure that includes the development and propagation of the failure surfaces, the amount of failed mass and runoff and the affected region. To assess the development of slope failure in more detail and to consider the potential danger of slopes after failure has initiated, the slope stability problem under external surcharge is analyzed by the distinct element method (DEM) and a laboratory model test in the present research. A more refined study about the development of failure, microcosmic failure mechanisms and the post-failure mechanisms of slopes will be carried out. The numerical modeling method and the various findings from the present work can provide an alternate method of analysis of slope failure, which can give additional information not available from the classical methods of analysis.

scholarly journals Laboratory and 3-D-distinct element analysis of failure mechanism of slope under external surcharge

2014 ◽  
Vol 2 (9) ◽  
pp. 5937-5970 ◽  
Author(s):  
N. Li ◽  
Y. M. Cheng
Keyword(s):  
Slope Stability ◽  
Failure Mechanism ◽  
Slope Failure ◽  
Slip Surface ◽  
Distinct Element ◽  
Laboratory Model ◽  
Element Analysis ◽  
Additional Information ◽  
Major Disaster ◽  
Failure Conditions

Abstract. Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient details. There are however increasing interest on the consequences after the initiation of failure which includes the development and propagation of the failure surfaces, the amount of failed mass and runoff and the affected region. To assess the development of slope failure in more details and to consider the potential danger of slopes after failure has initiated, the slope stability problem under external surcharge is analyzed by the distinct element method (DEM) and laboratory model test in the present research. A more refined study about the development of failure, microcosmic failure mechanism and the post-failure mechanism of slope will be carried out. The numerical modeling method and the various findings from the present work can provide an alternate method of analysis of slope failure which can give additional information not available from the classical methods of analysis.

Slope failure characteristics and stabilization methods

2007 ◽  
Vol 44 (4) ◽  
pp. 377-391 ◽  
Author(s):  
H (Joanna) Chen ◽  
S H Liu
Keyword(s):  
Numerical Model ◽  
Slope Failure ◽  
Slip Surface ◽  
Distinct Element ◽  
Distinct Element Method ◽  
Soil Nails ◽  
Failure Characteristics ◽  
Stabilization Methods ◽  
Installation Angle ◽  
Element Method

This paper presents numerical and laboratory experiments to investigate slope failure characteristics and commonly used slope stabilization methods. Using an improved distinct element method, the interparticle adhesive force is incorporated with a modified numerical model to account for the effect of suction. The model is validated through laboratory tilting box tests. Calculated slope failure angles are consistent with experimental observations. Different patterns of slip surface are also identified. Furthermore, the modified numerical model quantifies the micromechanical characteristics of the interparticle network and their evolutions during shear deformation. The calculations show that the maximum ratio of shear stress to normal stress takes place when the contact plane coincides with the mobilized plane, whereas the minimum value occurs when it is parallel to the directions of principal stresses. On this basis, we propose the optimal installation angle of soil nails along the minor principal stress (σ3) direction. The effectiveness of this approach is evaluated through tilting box tests. Two commonly used slope surface stabilization methods are also experimentally investigated.Key words: distinct element method, tilting box test, slip surface, optimal installation angle of soil nails.

Experimental Study on Slope Stability with Soil Mixed Rocks under Rainfall

2012 ◽  
Vol 170-173 ◽  
pp. 506-510
Author(s):  
Fang Cai Zhu ◽  
Yue Yang ◽  
Chun Ming Chen
Keyword(s):  
Experimental Study ◽  
Slope Stability ◽  
Water Content ◽  
Slope Failure ◽  
Western China ◽  
Laboratory Model ◽  
Small Scale ◽  
Loss Of Life ◽  
Key Factor ◽  
Scale Failure

Rainfall is a key factor that triggers failure of slopes. Due to development of western China, there are more and more slopes with soils mixed rocks, with rainfall effect, some of them will fail, which will lead to loss of life and property. In this paper, a laboratory model was used to simulate to study slope failure of this type under rainfall. Along with rainfall, water infiltrated into the slope, and water content increased steadily and kept almost constant, settlement of inner zone increased with different magnitude and reached almost constant value, and cracks formed on the top, small scale failure occurred.

Slope stability study of the 2001 Taipei National University of the Arts landslide

2020 ◽  
Author(s):  
Chien Liu ◽  
Cheng-Han Lin ◽  
Ching Hung
Keyword(s):  
Slope Stability ◽  
Junior High School ◽  
Factor Of Safety ◽  
Slope Failure ◽  
Limit Equilibrium ◽  
Equilibrium Analysis ◽  
Soil Parameters ◽  
Element Analysis ◽  
The Arts ◽  
National University

<p>Situated within a subtropical and mountainous region where frequent typhoons hit, rainfall-induced landslides have been a critical issue in Taiwan. On September 29, 2001, due to the torrential rainfall brought by the Typhoon Nari and Lekima, a downslope in Taipei National University of the Arts failed. The sliding source hit and severely damaged the Tao-Yuan junior high school. Before the 2001 Taipei National University of the Arts landslide, several landslides had already occurred in this landslide-prone region. In this study, a two-dimensional (2D) slope stability analysis, based on the limit equilibrium analysis (LEA), is conducted to analyze the 2001 Taipei National University of the Arts landslide. LEA has been the most popular and widely used technique given that it can estimate the factor of safety of a slope with some preliminary site investigation information. By comparing the failure surface and factor of safety (FOS) suggested in the post-disaster report [1], reasonable soil parameters, which are in an agreement with the experimental results [1], can be obtained through the study. The obtained soil parameters can later be applied to coupled transient unsaturated seepage-stress finite element analysis (FEA) [2] that will help practical engineers to understand the onset of failure in the future study.</p><p> </p><p>REFERENCE</p><ol><li>Taiwan Professional Geotechnical Engineers Association. (2001). National Taipei University of the Arts tennis court down slope failure reason identification and long-term remediation plan suggestion work report.</li> <li>Hung, C., Liu, C. H., & Chang, C. M. (2018). Numerical investigation of rainfall-induced landslide in mudstone using coupled finite and discrete element analysis. Geofluids, 2018.</li> </ol>

scholarly journals Dynamic and Static Combination Analysis Method of Slope Stability Analysis during Earthquake

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
Liang Lu ◽  
Zongjian Wang ◽  
Xiaoyuan Huang ◽  
Bin Zheng ◽  
Katsuhiko Arai
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Slope Failure ◽  
Numerical Procedure ◽  
Critical Value ◽  
Model Tests ◽  
Laboratory Model ◽  
Response Analysis ◽  
Seismic Slope Stability ◽  
Plastic Displacement

The results of laboratory model tests for simulating the slope failure due to vibration, including unreinforced slope and the slope reinforced by using geotextile, show that the slope failure occurs when a cumulative plastic displacement exceeds a certain critical value. To overcome the defects of conventional stability analysis, which evaluates the slope characteristics only by its strength parameters, a numerical procedure considering the stiffness and deformation of materials and geosynthetics is proposed to evaluate the seismic slope stability. In the proposed procedure, the failure of slope is defined when the cumulative plastic displacement calculated by a dynamic response analysis using actual seismic wave exceeds the critical value of displacement estimated by a static stability analysis considering seismic coefficient. The proposed procedure is applied to the laboratory model tests and an actual failure of slope in earthquake. The case study shows the possibility that the proposed procedure gives the realistic evaluation of seismic slope stability.

Three-dimensional strength-reduction finite element analysis of slopes: geometric effects

2012 ◽  
Vol 49 (5) ◽  
pp. 574-588 ◽  
Author(s):  
T.-K. Nian ◽  
R.-Q. Huang ◽  
S.-S. Wan ◽  
G.-Q. Chen
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Slip Surface ◽  
Boundary Effect ◽  
Three Dimensional ◽  
Strength Reduction ◽  
Infinite Length ◽  
Surface Geometry ◽  
Element Analysis ◽  
The Stability

The vast majority of slopes, both natural and constructed, exhibit a complex geometric configuration and three-dimensional (3D) state, whereas slopes satisfying the assumption of plane strain (infinite length) are seldom encountered. Existing research mainly emphasizes the 3D dimensions and boundary effect in slope stability analysis; however, the effect of complex geometric ground configuration on 3D slope stability is rarely reported. In this paper, an elastoplastic finite-element method using strength-reduction techniques is used to analyze the stability of special 3D geometric slopes. A typical 3D slope underlain by a weak layer with groundwater is described to validate the numerical modeling, safety factor values, and critical slip surface for the 3D slope. Furthermore, a series of special 3D slopes with various geometric configurations are analyzed numerically, and the effects of turning corners, slope gradient, turning arcs, and convex- and concave-shaped surface geometry on the stability and failure characteristics of slopes under various boundary conditions are discussed in detail.

scholarly journals Investigation of the Role of Crown Crack in Cohesive Soil Slope and Its Effect on Slope Stability Based on Extended Finite Element Method

2021 ◽  
Author(s):  
Yiding Bao ◽  
Yuchao Li ◽  
Yansong Zhang ◽  
Jianhua Yan ◽  
Xin Zhou
Keyword(s):  
Slope Stability ◽  
Extended Finite Element Method ◽  
Slope Failure ◽  
Slip Surface ◽  
Natural Soil ◽  
Tension Zone ◽  
Soil Slope ◽  
Extended Finite Element ◽  
Soil Slopes

Abstract Tensile cracks in soil slopes, especially developing at the crown, have been increasingly recognized as the signal of slope metastability. In this paper, the role of crown cracks in natural soil slopes was investigated and their effect on stability was studied. A numerical slope model based on the extended finite element method (XFEM) simulating the tensile behavior of soil was used. Before the simulation, a numerical soil tensile test was applied to validate the use of XFEM on tensile behavior of soil. Slope failure was simulated by using strength reduction technique, which can determine the potential slip surface of slope. The simulation results show that the crown crack forms in natural soil slopes when the plastic zone starts penetrating, and therefore it is reasonable to consider the crown crack as the signal of slope metastability. A sensitivity analysis shows that cracks are at the position of the tension zone or very long can obviously affect the slope stability. The stress variation analysis from the initial deformation to slip surface penetration shows that the slope is at a state of compressive stress initially. When plastic zone starts to penetrate, the upper part of slope generates tension zone, but the extent of tension zone is limited until slope failure. This shows why tensile cracks are difficult to form and be stretched in the deep part of the slope. The application of XFEM on slope stability analysis can be used to assess the tensile strength of soil and predict slope failure disaster.

Numerical Simulation and Analysis of Slope Stability under Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 147-150
Author(s):  
Xiao Xue Zhang ◽  
Bin Sheng Wang ◽  
Zhi Qiang Lv
Keyword(s):  
Numerical Simulation ◽  
Slope Stability ◽  
Slip Line ◽  
Slope Failure ◽  
Slip Surface ◽  
Flow Simulation ◽  
Particle Flow ◽  
Biaxial Test ◽  
Applied Loading ◽  
Particle Flow Simulation

By biaxial test of soil particle flow simulation program, the corresponding relationship between macro and micro parameters were obtained firstly. And then the slope model was established accord with these parameters. With this model, the slope stability under load were analyzed numerically, the influences of applied loading area on slope stability and damages were compared. Results shown that a slip surface came when slope was broken under a few loaded area, which is called the main slip lines. With the movement of the sliding, other landslide cracks began to appear; when subjected to a large load area, the slope undermining the main slip line was not obvious, but there were multiple landslide fissures, along with the movement of soil, the speed of slope failure increased, and severely damaged instantly.

SLOPE STABILITY AND DEFORMATION ANALYSIS UNDER DRAWDOWN CONDITIONS (CASE STUDY: RAMA 9 RESERVOIR)

2016 ◽  
Vol 78 (5-2) ◽  
Author(s):  
Werasak Raongjant ◽  
Meng Jing
Keyword(s):  
Slope Stability ◽  
Water Level ◽  
Factor Of Safety ◽  
Slope Failure ◽  
Deformation Analysis ◽  
Analysis Program ◽  
Element Analysis ◽  
Earth Slopes ◽  
Security Value

The Rapid drawdown condition is one of the most dangerous conditions for earth slopes. The change of water level in reservoir always causes a slope failure. This paper presents an investigation on the slope stability of the Rama 9 Reservoir under different drawdown conditions depending on the drawdown ratio, the drawdown rate and the loading conditions. Finite element analysis program PLAXIS 2D 2012 were applied to define the displacement and the factor of safety for slopes at selected positions. The results shown that, in the rapid drawdown condition for the drawdown ratio of 0.75, the factor of safety is 1.16.  In the slow drawdown condition for the drawdown ratio of 1.00, the factor of safety is 1.26. Both are less than the ratio of allowable security value of 1.3. For the Rama 9 Reservoir, the reduction of the water level should be controlled more carefully. 

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