scholarly journals Techniques to Evaluate and Remediate the Slope Stability in Overconsolidated Clay

2020 ◽  
Author(s):  
Herman Peiffer
Keyword(s):  
Numerical Analysis ◽  
Factor Of Safety ◽  
Field Tests ◽  
Integrated Approach ◽  
Numerical Approach ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Boom Clay ◽  
Unstable Slope ◽  
The Stability

In this chapter, the origin and remediation of an important sliding in the overconsolidated Boom Clay in Kruibeke (Belgium) is discussed. Local and environmental factors caused an unstable slope about 30 m deep, A larger sensitivity to erosion resulted finally in the instability of the slope. Because of the formation of fine cracks in the soil there was a possibility for the water to penetrate in the clay close to the surface, resulting in the presence of higher water pressures. Also, the presence of the excavator on top of the slope during exploitation had an important impact on the stress state of the soil. Both an analytical and numerical approach were used to estimate the factor of safety. Because of the change of the soil characteristics, the factor of safety decreases, which can be estimated through a numerical analysis (using the Strength Reduction Method). This chapter also discussed the applied techniques for the remediation using numerical analysis. Also, the importance of the field test is discussed. An integrated approach, using numerical analysis and field tests in combination, is capable of predicting the instability. This approach can also be used to evaluate the stability of the slope after remediation.

scholarly journals Stability Analysis of Jointed Rock Slope by Strength Reduction Technique considering Ubiquitous Joint Model

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ruili Lu ◽  
Wei Wei ◽  
Kaiwei Shang ◽  
Xiangyang Jing
Keyword(s):  
Rock Slope ◽  
Reduction Method ◽  
Domain Size ◽  
Jointed Rock ◽  
Strength Reduction ◽  
Hydropower Station ◽  
Strength Reduction Method ◽  
Vertical Side ◽  
The Stability ◽  
Jointed Rock Slope

In order to study the failure mechanism and assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station, the strength reduction method considering the ubiquitous joint model is proposed. Firstly, two-dimension numerical models are built to investigate the influence of the dilation angle of ubiquitous joints, mesh discretization, and solution domain size on the slope stability. It is found that the factor of safety is insensitive to the dilation angle of ubiquitous joints and the solution domain size but sensitive to the mesh discretization when the number of elements less than a certain threshold. Then, a complex three-dimension numerical model is built to assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station. During the strength reduction procedure, the progressive failure process and the final failure surface of the slope are obtained. Furthermore, the comparison of factors of safety obtained from strength reduction method and analytical solutions indicates that the effect of vertical side boundaries plays an important role in the stability of jointed rock slope, and the cohesive force is the main contribution to the resistant force of vertical side boundaries.

Stability Analysis of a 3D Vertical Slope with Transverse Earthquake Load and Surcharge

2011 ◽  
Vol 90-93 ◽  
pp. 676-679 ◽  
Author(s):  
Ting Kai Nian ◽  
Ke Li Zhang ◽  
Run Qiu Huang ◽  
Guang Qi Chen
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Failure Mode ◽  
Factor Of Safety ◽  
Three Dimensional ◽  
Strength Reduction ◽  
Reduction Procedure ◽  
Interesting Issue ◽  
Earthquake Load ◽  
The Stability

The stability and failure mode for a 3D vertical slope with transverse earthquake load and surcharge have been an interesting issue, especially in building excavation and wharf engineering. In order to further reveal the seismic and surcharge effect, a three-dimensional elasto-plastic finite element(FE) code combined with a strength reduction procedure is used to yield a factor of safety and failure mode for a vertical slopes under two horizontal direction pseudo-static(PS) coefficient and surcharge on the slope top, respectively. Comparative studies are carried out to investigate the effect of seismic coefficient, surcharge intensity and location on the stability and the failure mechanism for a 3D vertical slope including an inclined weak layer. Several important findings are also achieved.

scholarly journals Assessment of the Upstream Slope Stability of Darbandikhan Rockfill Dam during Drawdown

2021 ◽  
Vol 9 (1) ◽  
pp. 8-15
Author(s):  
Sirwan Gh. Salim ◽  
Krikar M. G. Noori
Keyword(s):  
Steady State ◽  
Numerical Analysis ◽  
Slope Stability ◽  
Water Level ◽  
Factor Of Safety ◽  
Computer Software ◽  
Loading Conditions ◽  
Upstream Slope ◽  
Rockfill Dam ◽  
The Stability

Earth and rockfill dams face a variety of loading conditions during lifetime. One of the most critical loading conditions is the rapid drawdown of water level after steady state conditions. Rapid drawdown may cause instability of upstream slope of the dam. The present work examines the stability of a rockfill dam under different drawdown rates in terms of factor of safety for the upstream slope of the dam. For this purpose, a computer software named GeoStudio 2012 SEEP/W and SLOPE/W has been used for the numerical analysis. The results showed that the drawdown rate has a significant effect on stability of rockfill dam in which increasing the drawdown rate from 1 m/day to 10 m/day decreases the stability of the dam by 33%. Based on the outcomes, for the studied case the drawdown rate (1 m/day) can be recommended.

scholarly journals Dynamic Numerical Analysis of Displacement Restraining Effect of Inclined Earth-Retaining Structure during Embankment Construction

2019 ◽  
Vol 9 (11) ◽  
pp. 2213 ◽  
Author(s):  
Su-Won Son ◽  
Minsu Seo ◽  
Jong-Chul Im ◽  
Jae-Won Yoo
Keyword(s):  
Numerical Analysis ◽  
Maximum Stress ◽  
Lateral Displacement ◽  
Retaining Wall ◽  
Field Tests ◽  
Front Wall ◽  
Construction Process ◽  
Construction Methods ◽  
Excavation Process ◽  
The Stability

Retaining walls are generally used for temporary installations during the excavation process of a construction project. They are also utilized to construct embankments in order to extend a railway facility. In this case, a retaining wall is installed during the construction process and contributes to the resistance of large amounts of stress, including the railway load. However, it is generally difficult to retain walls to maintain their stability. Therefore, alternative construction methods, such as the use of an inclined earth-retaining wall, have been utilized to suppress the lateral displacement. The stability is verified in advance through field tests; however, the maximum stress acting on the railway is thought to be the concentrated railway load. In this study, a two-dimensional numerical analysis was conducted by changing the railway load to a dynamic load. The analysis was applied according to the number of H-piles of the same length (10 m) when only the front wall was installed and when a back support was also applied. It was determined that the lateral displacement of the latter case is smaller than that of the former, whereas the resistance to dynamic loading of the former case is greater.

Comparing slope stability analysis using limit equilibrium and finite elements simulations of deep-seated landslides along the western margin of the Main Ethiopian Rift

2021 ◽  
Author(s):  
Tesfay Kiros Mebrahtu ◽  
Thomas Heinze ◽  
Stefan Wohnlich
Keyword(s):  
Slope Stability ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Ethiopian Rift ◽  
Seismic Load ◽  
Main Ethiopian Rift ◽  
Western Margin ◽  
The Stability

<p>Landslides and ground failures are among the common geo-environmental hazards in many of the tectonically active hilly and mountainous terrains of Ethiopia, such as in the western margin of the Main Ethiopian Rift in Debre Sina area. Besides the geological preconditioning, bi-modal monsoon and seismic events in the tectonically highly active region are usually suspected triggers. In order to minimize the damage caused by the slope failure events, a detailed investigation of landslide-prone areas using numerical modelling plays a crucial role. The aim of this study is to assess the stability of slopes, to understand the relevant failure mechanisms, and to evaluate and compare safety factors calculated by the different available numerical methods. The stability was assessed for slopes of complex geometry and heterogeneous material using the limit equilibrium method and the shear strength reduction method based on finite elements. Furthermore, numerical analysis was done under static and pseudo-static loading using the horizontal seismic coefficient to model their stability during a seismic event. The slope stability analysis indicates that the studied slopes are unstable, and any small scale disturbance will further reduce the factor of safety and probably causing failure. The critical strength reduction factors from the finite element method are significantly lower than the factor of safety from the limit equilibrium method in all studied scenarios, such as Bishop, Janbu Simplified, Spencer and Morgenstern-Price. The difference is especially evident for heterogeneous slopes with joints, which often are initiation points for the failure planes. The simulations show that slope stability of landslide prone hills in the study area strongly depends on the saturation conditions and the seismic load. The studied slopes are initially close to failure and increased pore-pressure or seismic load are very likely triggers.</p>

Stability Analysis of Dump Slope Based on FEM Strength Reduction Method

2014 ◽  
Vol 501-504 ◽  
pp. 51-55 ◽  
Author(s):  
Chao Peng ◽  
Dong Ji ◽  
Liang Zhao ◽  
Zhen Yu Qian ◽  
Fen Hua Ren
Keyword(s):  
Safety Factor ◽  
Reduction Method ◽  
Strength Reduction ◽  
Production Costs ◽  
Open Pit ◽  
Strength Reduction Method ◽  
Reduction Algorithm ◽  
Safety Factors ◽  
Dump Slope ◽  
The Stability

An analysis on safety factor of slope through c - φ reduction algorithm by finite elements method is presented. When the system reaches instability, the numerical non-convergence occurs simultaneously. The safety factor is then obtained by c φ reduction algorithm. This paper, which combines with the actual situation of Jinduicheng open pit mine, analysis the stability of the limit height of the dump based on strength reduction of finite element method. And the value of slope safety factor is 1.25 to 1.30. The results show that calculating safety factors of the slope by ANSYS is in full conformity with the basic requirement of safety. That means, the dump is stable, which can reduce the production costs and benefit the enterprise.

The Numerical Calculation of Highway Slope Stability under the Influence of Rainfall

2012 ◽  
Vol 260-261 ◽  
pp. 907-911
Author(s):  
Yu Chen ◽  
Hui Yun Duan ◽  
Cheng Tao Zhou
Keyword(s):  
Reduction Method ◽  
Maximum Shear Stress ◽  
Landslide Hazard ◽  
Strength Reduction ◽  
Control Measures ◽  
Strength Reduction Method ◽  
The Finite Element Method ◽  
Landslide Hazards ◽  
The Stability ◽  
Water Saturated

The slope deformation and instability caused by rainfall is the most common geological hazard in the highway slope landslide hazards. This paper used the finite element method to analyze the stability of slop in a variety of water-saturated conditions based on the strength reduction method, and to get the mechanism of rainfall weakening the strength of landslide. The results shows that the slope landslide in the fully saturated state would be instability when the surface was muddy geotechnical (thickness about 5 m), but it could remain stable when the saturated rate was under 80%. Under the action of rainfall, the maximum shear stress of potential slip plane in this kind of slopes was in the landslide’s lower edge which has obvious stress concentraten. Therefore, slope control measures should be strengthened to prevent the occurrence of the landslide hazard in the lot of long rainy season.

scholarly journals Study on the Influence of Rainfall Infiltration on the High rock Slope of Open-pit Mine Stability using a New Nonlinear Strength Reduction Method

2021 ◽  
Author(s):  
Tianbai Zhou ◽  
Lingfan Zhang ◽  
Jian Cheng ◽  
Jianming Wang ◽  
Xiaoyu Zhang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Reduction Method ◽  
Strength Reduction ◽  
Open Pit Mine ◽  
Open Pit ◽  
Strength Reduction Method ◽  
Rock Slopes ◽  
High Rock Slope ◽  
The Stability

Abstract Due to long-term mining, a series of high and steep rock slopes have been formed in the open-pit mine. For high rock slopes, rainfall infiltration is the main cause of landslide. Therefore, the stability analysis of high rock slope under rainfall has become a key issue in the open-pit mine engineering. In this work, aiming at the high stress condition of high rock slope, the instantaneous internal friction angle and instantaneous cohesion of rock mass under different stress states are deduced, and the a nonlinear strength reduction method for high rock slope is established according to the relationship between normal stress and shear stress of rock mass under the Hoke-Brown criterion. The numerical calculation results show that the factor of safety (FOS) for high rock slope calculated by the proposed method is more reasonable. Taking the southwest slope of Dagushan Iron Mine as the research background, the safety factors of high rock slope under different rainfall conditions are calculated by COMSOL Multiphysics. And the stability analysis of high rock slope in open-pit mine under rainfall are carried out.

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