Reanalysis of a municipal landfill slope failure near Cincinnati, Ohio, USA

2007 ◽  
Vol 44 (1) ◽  
pp. 33-53 ◽  
Author(s):  
Ashok K Chugh ◽  
Timothy D Stark ◽  
Kees A DeJong
Keyword(s):  
Failure Mechanism ◽  
Continuum Mechanics ◽  
Slope Failure ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Continuum Models ◽  
Surface Geometry ◽  
Municipal Landfill ◽  
Analysis Computer ◽  
Analysis Computer Program

The March 1996 slope failure in a municipal solid waste landfill near Cincinnati, Ohio, USA, is reanalyzed using continuum-mechanics-based procedures implemented in the computer programs FLAC and FLAC3D. A failure mechanism, based on the field observations of the failure, is used for the analyses. The failure mechanism is also implemented in a limit-equilibrium-based slope stability analysis computer program, SSTAB2, to simulate the observed translational character of the failure. The reanalysis results (failure surface, factor-of-safety (FoS), and displacement) from the continuum models are in general agreement with the field data. The FoS values from SSTAB2, FLAC, and FLAC3D range in the expected order. Overall, the reanalysis results supplement previously reported failure analyses. This paper serves two functions: (1) it documents the results of reanalysis using a different (from the previously published) failure mechanism hypothesis for the 1996 landfill slope failure near Cincinnati, Ohio; and (2) it demonstrates the use of 2-D and 3-D continuum models to study: (i) onset of instability; (ii) failure surface geometry and location; and (iii) displacements associated with slope failures.Key words: municipal landfill, slope failure, numerical analysis, limit equilibrium, continuum mechanics, displacement.

scholarly journals Failure Mechanism and Factor of Safety for Spatially Variable Undrained Soil Slope

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Liang Li ◽  
Xuesong Chu
Keyword(s):  
Random Field ◽  
Failure Mechanism ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Vertical Direction ◽  
Failure Surface ◽  
Cohesive Soil ◽  
Soil Slope ◽  
The Stability ◽  
Undrained Soil

This paper aims to investigate the differences in factor of safety (FS) and failure mechanism (FM) for spatially variable undrained soil slope between using finite element method (FEM) , finite difference method (FDM), and limit equilibrium method (LEM). The undrained shear strength of cohesive soil slope is modeled by a one-dimensional random field in the vertical direction. The FS and FM for a specific realization of random field are determined by SRT embedded in FEM- and FDM-based software (e.g., Phase2 6.0 and FLAC) and LEM, respectively. The comparative study has demonstrated that the bishop method (with circular failure surface) exhibits performance as fairly good as that of SRT both in FS and FM for the undrained slope cases where no preferable controlling surfaces such as hydraulic tension crack and inclined weak seams dominate the failure mechanism. It is, however, worthwhile to point out that unconservative FM is provided by the Bishop method from the aspect of failure consequence (i.e., the failure consequence indicated by the FM from the Bishop method is smaller than that from SRT). The rigorous LEM (e.g., M-P and Spencer method with noncircular failure surface) is not recommended in the stability analysis of spatially variable soil slopes before the local minima and failure to converge issues are fully addressed. The SRT in combination with FEM and/or FDM provides a rigorous and powerful tool and is highly preferable for slope reliability of spatially variable undrained slope.

Pseudo-Dynamic Bearing Capacity of Shallow Strip Footing Resting on c-Φ Soil Considering Composite Failure Surface

2015 ◽  
Vol 6 (2) ◽  
pp. 12-34 ◽  
Author(s):  
Arijit Saha ◽  
Sima Ghosh
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Friction Angle ◽  
Strip Footing ◽  
Unit Weight ◽  
Composite Failure ◽  
Seismic Accelerations ◽  
Seismic Bearing Capacity

The evaluation of bearing capacity of shallow strip footing under seismic loading condition is an important phenomenon. This paper presents a pseudo-dynamic approach to evaluate the seismic bearing capacity of shallow strip footing resting on c-F soil using limit equilibrium method considering the composite failure mechanism. A single seismic bearing capacity coefficient (N?e) presents here for the simultaneous resistance of unit weight, surcharge and cohesion, which is more practical to simulate the failure mechanism. The effect of soil friction angle(F), soil cohesion(c), shear wave and primary wave velocity(Vs, Vp) and horizontal and vertical seismic accelerations(kh, kv) are taken into account to evaluate the seismic bearing capacity of foundation. The results obtained from the present analysis are presented in both tabular and graphical non-dimensional form. Results are thoroughly compared with the existing values in the literature and the significance of the present methodology for designing the shallow strip footing is discussed.

scholarly journals Stability Evaluation of a Toppling Deformed Body in Miaowei Hydropower Station

2019 ◽  
Vol 131 ◽  
pp. 01069
Author(s):  
Yangbo Ding ◽  
Faming Zhang ◽  
Zhenghao Yu ◽  
Yushan Ma
Keyword(s):  
Water Level ◽  
Failure Mechanism ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Discrete Element ◽  
Stability Factor ◽  
Topographic Map ◽  
Deformation Degree ◽  
Element Simulation ◽  
Stress Changes

By analyzing the instability characteristics of deformed body after impoundment and using limit equilibrium algorithm and UDEC discrete element simulation, the failure mechanism and stability of deformed body are studied in the paper. According to the deformation degree and instability characteristics of the deformed body in different storage periods, the mechanism of instability is analyzed. Based on the regional topographic map, a two-dimensional limit equilibrium model is established to calculate the potential failure surface range and slope stability factor of QD18 deformed body under the conditions of 1314m, 1364m and 1401m water level storage. And the displacement nephogram, velocity nephogram and rock block deformation map of the deformed body under the condition of 1401 m water level are simulated by using the discrete element software, and the stress changes of each part of the deformed body after water storage are analyzed, and the failure mechanism is summarized.

Seismic Bearing Capacity Factor Considering Composite Failure Mechanism

2018 ◽  
Vol 9 (1) ◽  
pp. 65-77
Author(s):  
Swetha S Kurup ◽  
Sreevalsa Kolathayar
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Static Analysis ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Shallow Foundation ◽  
Capacity Factor ◽  
Composite Failure ◽  
Seismic Bearing Capacity ◽  
Bearing Capacity Factor

This article describes how the design of shallow foundation needs complete knowledge about bearing capacity. During earthquakes additional lateral force acts at the foundation bed which reduces the bearing capacity. Most of the literature present either the pseudo static analysis or assume a planar failure surface to estimate seismic bearing capacity factors. Here, a pseudo dynamic approach that considers the time dependent effect of earthquake loading is employed. A composite failure surface has been considered for a more realistic estimation of seismic bearing capacity. New expressions were formulated to arrive at the seismic bearing capacity factor, considering the forces acting on the failure wedge based on the limit equilibrium approach. The effect of soil friction angles and the seismic peak of horizontal ground accelerations on the seismic bearing capacity were studied using the proposed method. It was observed that present pseudo-dynamic analysis with a composite failure mechanism gives lower values of seismic bearing capacity factors when compared to pseud- static analysis.

Shaking table tests and stability analysis of steep nailed slopes

2005 ◽  
Vol 42 (5) ◽  
pp. 1264-1279 ◽  
Author(s):  
Yung-Shan Hong ◽  
Rong-Her Chen ◽  
Cho-Sen Wu ◽  
Jian-Ren Chen
Keyword(s):  
Slope Failure ◽  
Shaking Table Test ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Soil Mass ◽  
Shaking Table ◽  
Seismic Resistance ◽  
Shaking Table Tests ◽  
Strong Excitation ◽  
Static Approach

Shaking table tests were performed on five model slopes to examine the effects of the angle and length of the nails and the frequency of excitation on the seismic resistance and failure mechanism of the slopes. Seismic excitation was also applied to slopes at various angles. Experimental results showed that nails markedly improved the seismic resistance of all model steep slopes. Additionally, nailed slopes exhibit characteristics of ductility under strong excitation. The angle of the nails influences the deformation of the slope but only slightly affects seismic resistance. An increase in the length of the nails increased the seismic resistance of the slope and reduced the displacement of the facing only when subjected to strong excitation. The slope at an angle of 90° to the horizontal has a markedly lower seismic resistance than that at 80°. The rocking of the model slope was strong for the slope with inclined nails and the slope at 90° to the horizontal. The failure surface of the soil mass is approximately a bilinear surface; the pullout of nails from the lower rows of nails caused total slope failure. The seismic resistance of a nailed slope is categorized viz. response of the models by three stages: stable, seismic resistance, and incipient collapse phases. Critical seismic acceleration coefficients of all models are evaluated and compared with values predicted by a developed pseudo-static, limit-equilibrium-based slope stability approach, which postulates a two-wedge failure mechanism.Key words: shaking table test, steep nailed slope, seismic resistance, pseudo-static approach.

The Bearing Capacity and Failure Mechanism of Foundations near Slope Based on Nondimensional Parameters

2014 ◽  
Vol 501-504 ◽  
pp. 107-110
Author(s):  
Yang Jiang ◽  
Yue Xin She ◽  
Bao Hai Chen ◽  
Hua Rong Shen
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Slope Failure ◽  
Failure Surface ◽  
Considerable Change ◽  
Strength Ratio ◽  
The Finite Element Method ◽  
Ground Failure ◽  
Special Case ◽  
Flat Ground

The foundation on slope problem is a special case of the very large bearing capacity problem. Researchers have studied the bearing capacity of slopes as such problems arise quite frequently in practice. The aim of this paper is to study the effect that changing the position of an infinitely long strip foundation, from the edge of the slope to a certain distance away, has on the bearing capacity of a slope. The influence of various nondimensional parameters, such as strength ratio, slope height ratio and so on, on the bearing capacity of slope foundation is also analyzed by the finite element method. Conclusions are as follows: as the foundation is moved away from the slope by increasing D/B, there is a change over point from a slope failure mechanism to a flat ground failure mechanism. As the strength ratio increases for a set D/B, there is a considerable change in the shape of the failure surface initially, followed by only minor changes from strength ratio 10 onwards and so on.

scholarly journals The Hydromechanical Interplay in the Simplified Three-Dimensional Limit Equilibrium Analyses of Unsaturated Slope Stability

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73
Author(s):  
Panagiotis Sitarenios ◽  
Francesca Casini
Keyword(s):  
Analytical Solution ◽  
Slope Stability ◽  
Slope Failure ◽  
Failure Modes ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Stability Limit ◽  
Smooth Transition

This paper presents a three-dimensional slope stability limit equilibrium solution for translational planar failure modes. The proposed solution uses Bishop’s average skeleton stress combined with the Mohr–Coulomb failure criterion to describe soil strength evolution under unsaturated conditions while its formulation ensures a natural and smooth transition from the unsaturated to the saturated regime and vice versa. The proposed analytical solution is evaluated by comparing its predictions with the results of the Ruedlingen slope failure experiment. The comparison suggests that, despite its relative simplicity, the analytical solution can capture the experimentally observed behaviour well and highlights the importance of considering lateral resistance together with a realistic interplay between mechanical parameters (cohesion) and hydraulic (pore water pressure) conditions.

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