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>

Progressive failure of the Carsington Dam: a numerical study

1992 ◽  
Vol 29 (6) ◽  
pp. 971-988 ◽  
Author(s):  
Z. Chen ◽  
N. R. Morgenstern ◽  
D. H. Chan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Factor Of Safety ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Equilibrium Analysis ◽  
Element Analysis ◽  
Limit Equilibrium Analysis ◽  
The Finite Element Analysis ◽  
Yellow Clay

The mechanism of progressive failure is well understood as one which involves nonuniform straining of a strain-weakening material. Traditional limit equilibrium analysis cannot be used alone to obtain a rational solution for progressive failure problems because the deformation of the structure must be taken into account in the analysis. The failure of the Carsington Dam during construction in 1984 has been attributed to progressive failure of the underlying yellow clay and the dam core materials. The dam was monitored extensively prior to failure, and an elaborate geotechnical investigation was undertaken after failure. The limit equilibrium analysis indicated that the factors of safety were over 1.4 using peak strength of intact clay material or 1.2 based on reduced strength accounting for preshearing of the yellow clay layer. Factors of safety were found to be less than unity if residual strengths were used. The actual factor of safety at failure was, of course, equal to one. By using the finite element analysis with strain-weakening models, the extent and degree of weakening along the potential slip surface were calculated. The calculated shear strength was then used in the limit equilibrium analysis, and the factor of safety was found to be 1.05, which is very close to the actual value of 1.0. More importantly, the mechanism of failure and the initiation and propagation of the shear zones were captured in the finite element analysis. It was also found that accounting explicitly for pore-water pressure effects using the effective stress approach in the finite element and limit equilibrium analyses provides more realistic simulations of the failure process of the structure than analyses based on total stresses. Key words : progressive failure, strain softening, finite element analysis, dams.

scholarly journals Assessments of Geotechnical Condition of Landslide Sites and Slope Stability Analysis Using Limit Equilibrium Method in Goncha Siso Eneses Area, Northwestern Ethiopia

2020 ◽  
Author(s):  
Azemeraw Wubalem
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Stability Analysis ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Slope Failure ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Slope Stability Analysis ◽  
Equilibrium Method

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.

scholarly journals Slope Stability Analysis of Highway Embankment with Different Height and Slope by Varying the Properties of Soil

2021 ◽  
Vol 9 (VII) ◽  
pp. 3066-3072
Author(s):  
Prof. R. Y. Kale
Keyword(s):  
Internal Friction ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Practical Importance ◽  
Equilibrium Analysis ◽  
Unit Weight ◽  
Cross Sectional ◽  
Angle Of Internal Friction ◽  
Side Slope

The analysis of slope stability has received wide attention nowdays because of its practical importance. To provide steepest slopes which are stable and safe, various investigation are ongoing. The main objective of the project is to analyze slope of embankment by calculating factor of safety. So that an appropriate side slope can be chosen and use for the construction of highway. For this, limit equilibrium analysis has been done using GEO5 software. Swedish circle method (Graphically) has been used to performed manually analysis. In the present study, data collected from the site which is located near Shivni Village, Ner-Yavatmal road. “The construction of Samruddhi Mahamarg” is being constructed at that site. It is having high embankment heights upto 9meter. The values of unit weight of soil(γ), angle of internal friction(ϕ), cross sectional details of embankment and side slope of embankment were taken from that site. In this study, embankment of different heights (3 to 9m) under different 8 slopes (i.e. 1:2, 1:1.75, 1:1.5, 1:1.25, 1:1, 1:0.83, 1:0.7, 1:0.58), different values of cohesion and friction angle were considered. The analysis has been performed on two different cases: Case I stands for single layer of soil and Case II stands for double layer of soil by varying the value of cohesion and angle of internal friction the changes occur in the value of factor of safety were checked by comparing both results obtained by manual method and by GEO5 software. From this investigation it is found that increasing the value of cohesion and angle of internal friction, the factor of safety against slope stability increases. And for a particular height of embankment factor of safety increases with increase in the flatness of slope. From these results, it is better to use C-ϕ soil rather than ϕ soil as it gives maximum FOS as compared to sandy soil. From the analysis of doubled layered soil, it has been concluded that condition 2(with both soil cohesive) found satisfactory better with respect to condition 1(when one soil cohesive and one soil sandy). By considering condition 2 (both soil cohesive), it has been found that the increment of 25 to 30% in the FOS of condition 1 takes place.

scholarly journals Slope Stability Evaluation of Geosynthetic Reinforced Soil

2019 ◽  
Vol 8 (4) ◽  
pp. 7143-7147
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Friction Angle ◽  
Calculation Model ◽  
Reinforced Soil ◽  
Unit Weight ◽  
Soil Parameters

The slippery of natural slope is sometimes ruled by combination of soil parameters and earthquake characteristics. Geotextiles could be a reinforcing materials and an application in numerous areas still as in geotechnical application to supply additional lateral restraint and forestall the high rise hill from failure. The analysis was aimed to analyze slope stability analysis, strengthened the Finite slope with non-woven geotextiles. The modal of hill was created within the SLOPE/W software system of GeoStudio that is predicated on limit equilibrium of slope analysis. The results of issue of safety square measure compared while not and with use of geotextiles in several layers. The issue of safety of slope failure will increase from three.437M to 9.978M victimization 3 layers of geotextiles at optimum height. Thus, this study confirms that the non-woven geotextiles may be applied in slope so as to enhance the soundness of natural or mam-made slope. During this regard, special stress is given to the sensitivity of the Calculation model input parameters like friction angle, cohesion, Pore water pressure and unit weight of soil that ought to contribute to raising awareness regarding these problems, as a requirement to create the proper selections and optimum technical resolution during this space.

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. 

scholarly journals Some Remarks on the Use of Deterministic and Probabilistic Approaches in the Evaluation of Rock Slope Stability

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 163
Author(s):  
Paolo Budetta
Keyword(s):  
Slope Stability ◽  
Failure Probability ◽  
Slope Failure ◽  
Rock Slope ◽  
Limit Equilibrium ◽  
Mean Value ◽  
Probabilistic Methods ◽  
Equilibrium Analysis ◽  
Rock Slope Stability ◽  
Deterministic And Probabilistic Approaches

The rock slope stability assessment can be performed by means of deterministic and probabilistic approaches. As the deterministic analysis needs only representative values (generally, the mean value) for each physical and geo-mechanical parameter involved, it does not take into account the variability and uncertainty of geo-structural and geo-mechanical properties of joints. This analysis can be usually carried out using different methods, such as the Limit Equilibrium method or numerical modeling techniques sometimes implemented in graphical tests to identify different failure mechanisms (kinematic approach). Probabilistic methods (kinetic approach) aimed to calculate the slope failure probability, consider all orientations, physical characters and shear strength of joints and not only those recognized as kinematically possible. Consequently, the failure probability can be overestimated. It is, therefore, considered more realistic to perform both kinematic and kinetic analyses and to calculate a conditional probability given by the product of the kinematic and kinetic probabilities assuming that they are statistically independent variables. These approaches have been tested on two rock slopes in the Campanian region of Southern Italy affected by possible plane and wedge failures, respectively. Kinematic and kinetic probabilities have been evaluated both by means of the Markland’s test and the Monte Carlo simulation. Using the Eurocode 7, also a deterministic limit equilibrium analysis was performed. The obtained results were compared and commented on.

scholarly journals Assessments of Geotechnical Condition of Landslide Sites and Slope Stability Analysis Using Limit Equilibrium Method around Gundwin Town Area, Northwestern Ethiopia

2020 ◽  
Author(s):  
Azemeraw Wubalem Azeze
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Stability Analysis ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Slope Failure ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Slope Stability Analysis ◽  
Equilibrium Method

Abstract The study 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 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.

scholarly journals Engineering Geological and Geotechnical studies of Taprang landslide, west-central Nepal: An approach for slope stability analysis

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Ashok Sigdel ◽  
Radha Krishna Adhikari
Keyword(s):  
Electrical Resistivity ◽  
Stability Analysis ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Slope Stability Analysis ◽  
Grain Size Analysis ◽  
Soil Parameters ◽  
Seismic Load ◽  
Geotechnical Studies

Detailed investigation of Taprang landslide was carried out in order to understand the surface, subsurface lithological information and physical properties of soil by using multi-disciplinary methods such as engineering geological, geophysical and geotechnical studies for the determination of factor of safety for slope stability analysis.  Geological study was carried out by detail mapping of surface geology, soil condition, properties of bedrock and its discontinuities. The geophysical survey (Electrical Resistivity Tomography-ERT) were carried out to know the electrical resistivity of soil for identifying the groundwater table and hence slip surface of the landslide. Geotechnical analysis such as grain size analysis, liquid limit and direct shear test were carried out in order to evaluate soil classification, moisture content, cohesion and the angle of internal friction of soil for knowing the strength the soil. These soil parameters indicate the soil is very low strength. The combination of these results were used for calculating the factor of safety (FoS) by Limit Equilibrium Method (LEM) proposed by Bishop and Janbu methods. The result of factor of safety in the Taprang landslide demonstrates that the slope become stable in drained (dry) condition, remain ultimate stage in undrained (wet) condition and finally failure occurs if applied the seismic load in both drained and undrained conditions.

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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