Slope Failure of Embankment Dam under Extreme Flooding Conditions: Comparison of Limit Equilibrium and Continuum Models

Author(s):  
Kevin S. Richards ◽  
Krishna R. Reddy
2007 ◽  
Vol 44 (1) ◽  
pp. 33-53 ◽  
Author(s):  
Ashok K Chugh ◽  
Timothy D Stark ◽  
Kees A DeJong

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.


Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73
Author(s):  
Panagiotis Sitarenios ◽  
Francesca Casini

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.


2019 ◽  
Vol 9 (4) ◽  
pp. 4469-4473
Author(s):  
D. A. Mangnejo ◽  
S. J. Oad ◽  
S. A. Kalhoro ◽  
S. Ahmed ◽  
F. H. Laghari ◽  
...  

Slope instability may be a result of change in stress conditions, rise in groundwater table and rainfall. Similarly, many slopes that have been stable for several years can abruptly fail due to changes in geometry, weak soil shear strength or as the effect of an external force. Debris flows (i.e. slope failures) take place without any warning and can have devastating results. So, it is vital to understand the slope failure mechanism and adopt safety prevention measures. Soil nailing is one of the widely used stabilization techniques for soil slopes. In this study, soil nail technique is proposed to upgrade the existing slope in clay. A parametric study was conducted to understand the effects of different nail diameter (i.e. 25mm and 40mm) and nail inclination (i.e. 200, 250, 300, 350 and 400) on slope stability. Morgenstern-Price (i.e. limit equilibrium) method was used to determine the factor of safety of the slope. It was found that the factor of safety of the existing slope improved significantly with three rows of 40mm diameter nail at an inclination of 400.


2005 ◽  
Vol 2 ◽  
pp. 305-308 ◽  
Author(s):  
S. Dapporto ◽  
P. Aleotti ◽  
N. Casagli ◽  
G. Polloni

Abstract. On 14-16 November 2002 the North Italy was affected by an intense rainfall event: in the Albaredo valley (Valtellina) more than 200 mm of rain fell triggering about 50 shallow landslides, mainly soil slips and soil slip-debris flows. Landslides occurred above the critical rainfall thresholds computed by Cancelli and Nova (1985) and Ceriani et al. (1994) for the Italian Central Alps: in fact the cumulative precipitation at the soil slips initiation time was 230 mm (in two days) with a peak intensity of 15 mm/h. A coupled analysis of seepage and instability mechanisms is performed in order to evaluate the potential for slope failure during the event. Changes in positive and negative pore water pressures during the event are modelled by a finite element analysis of water flow in transient conditions, using as boundary condition for the nodes along the slope surface the recorded rainfall rate. The slope stability analysis is conducted applying the limit equilibrium method, using pore water pressure distributions obtained in the different time steps by the seepage analysis as input data for the calculation of the factor of safety.


2020 ◽  
Author(s):  
Azemeraw Wubalem

Abstract Goncha Siso Eneses area is located in northwestern Ethiopia where landslide incidence is active. The landslide incidence in the area resulted in the devastation of 233.1 hectares of cultivated and non-cultivated land, death of eight people, demolition of five houses, displaced 90 households, and 45 households are under risk. The slope failure in this area also caused tilting of the power line, tilting of two houses, cracking of three-houses floor, failed of bridge and blocking of streams as well as springs. The purpose of this research is to evaluate the cause, failure mechanism, landslide distribution, geotechnical condition of the site, slope stability analysis, and factor of safety determination. Soil sampling, laboratory test, terrain characteristics, groundwater-surface manifestation characterization, groundwater depth determination, slope stability analysis, and factor of safety calculation were the most important activities employed in this research work. Using disturbed and undisturbed soil samples of the selected slope section, Atterberg limit (liquid limit & plastic limit), natural soil moisture, unit weight, specific gravity, and shear strength parameters (cohesion & internal friction angle) test were carryout as ASTM standard. The most marginal factor of safety of the area is determined based on the general limit equilibrium method that encompasses different methods inside using slope/w in GeoStudio 2018 software package considering various groundwater conditions for all selected slope sections. The factor of safety for all selected slope sections of the various method under different groundwater conditions is less than one. Based on the finding of field observation and laboratory results, landslide types (rock/soil slides, rock/earth fall, debris/earth flow, & soil creeping) and landslide factors of the study area (slope angle, slope shape, slope modification, land use, groundwater, soil type, and rainfall) are determined. This research finds out that the soil has a great contribution to slope failure in the study area, besides the soil moisture and improper land use practice.


2020 ◽  
Author(s):  
Chien Liu ◽  
Cheng-Han Lin ◽  
Ching Hung

<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>


2014 ◽  
Vol 919-921 ◽  
pp. 637-640 ◽  
Author(s):  
Qi Zhang

The slope failure of high fill embankment have a large proportion under self-weight and external conditions,Because of the complexity of the soil deformation and stress,General methods such as the limit equilibrium and numerical analysis have their own limitations,The paper takes high fill subgrade engineering in Fujian province as the background.Adopting analytical method and finite element method calculate the stability coefficient and lateral displacement of high fill embankment slope.moreover,Making a comprehensive judgement to the stability of the slope by comparing with the actual value.The results show that calculation results of these two methods are close.Which can make accurate predictions on high slope stability and determine a judgement.and provides an effective method for the design and construction of the similar project.


2014 ◽  
Vol 580-583 ◽  
pp. 364-370
Author(s):  
An Lin Shao ◽  
Hai Long Feng

<span><p class="TTPAbstract"><span lang="EN-US">The Yanqianshan<a name="OLE_LINK94"></a><a name="OLE_LINK93"></a> iron mine is preparing to transform from an open-pit mine to an underground mine. We adopt the <a name="OLE_LINK104"></a><a name="OLE_LINK103"></a>non-pillar sublevel caving approach to exploit the particularly thick steep ore bodies within the range from -183 m to -500 m from top to bottom. According to the features of ore body distribution and the approaches of exploitation, we expect that underground mining will result in <a name="OLE_LINK102"></a><a name="OLE_LINK101"></a>the loss of stability on the northern slope of the open pit, causing traction-type landslides. Moreover, along with increasing the depth of the mining operation, the range of slope failure will continue to expand and further affect the safety of drainage features and roads distributed on the north side of the open pit. For this purpose, we select f</span><span lang="EN-US">our</span><span lang="EN-US"> sections along the trending direction of ore bodies and apply the limit equilibrium method to predict the failure process and characteristics on the northern slope according to the stratified mining process.</span><span lang="EN-US"><o:p></o:p></span></p>


Sign in / Sign up

Export Citation Format

Share Document