scholarly journals Design of Medium Depth Drainage Trench Systems for the Mitigation of Deep Landsliding

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 174
Author(s):  
Federica Cotecchia ◽  
Rossella Petti ◽  
Dario Milella ◽  
Piernicola Lollino
Keyword(s):  
Slip Surface ◽  
Limit Equilibrium ◽  
Drainage System ◽  
Field Studies ◽  
Stability Factor ◽  
Deep Drainage ◽  
Predisposing Factor ◽  
Mitigation Measure ◽  
Transient Seepage ◽  
The Stability

For those slopes where the piezometric regime acts as internal landslide predisposing factor, drainage may represent a more effective mitigation measure than other structural interventions. However, drainage trenches have been generally considered as mitigation measure solely for shallow landslides. More recently, instead, some authors show that the variation in piezometric conditions at large depth is not negligible when medium depth drainage trenches are involved. The paper presents the results of finite element analyses of the transient seepage induced by the installation of systems of drainage trenches of different geometric parameters, and the effect of the drainage system on the stability factor of the slip surface, through 2D limit equilibrium analyses. The pilot region is the Daunia Apennines, where field studies have led to recognize for most of the landslides a “bowl-shaped” slip surface; the results accounting for the Fontana Monte slope at Volturino (Italy), selected as prototype landslide in the assessment of the stabilization efficacy of deep drainage trench systems, is discussed in the following. The study aims at providing indications about the design of the drainage trenches to reduce the pore water pressures on a deep slip surface of such type.

Landslide Simulation Using Limit Equilibrium and Finite Element Method

2016 ◽  
Vol 857 ◽  
pp. 555-559 ◽  
Author(s):  
Zuhayr Md Ghazaly ◽  
Mustaqqim Abdul Rahim ◽  
Kok Alfred Chee Jee ◽  
Nur Fitriah Isa ◽  
Liyana Ahmad Sofri
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Main Concern ◽  
Analysis Method ◽  
Stability Of Slope ◽  
The Stability ◽  
Element Method

Slope stability analysis is one of the ancient tasks in the geotechnical engineering. There are two major methods; limit equilibrium method (LEM) and finite element method (FEM) that were used to analyze the factor of safety (FOS) to determine the stability of slope. The factor of safety will affect the remediation method to be underdesign or overdesign if the analysis method was not well chosen. This can lead to safety and costing problems which are the main concern. Furthermore, there were no statement that issued one of the analysis methods was more preferred than another. To achieve the objective of this research, the soil sample collected from landslide at Wang Kelian were tested to obtain the parameters of the soils. Then, those results were inserted into Plaxis and Slope/W software for modeling to obtain the factor of safety based on different cases such as geometry and homogenous of slope. The FOS obtained by FEM was generally lower compared to LEM but LEM can provide an obvious critical slip surface. This can be explained by their principles. Overall, the analysis method chosen must be based on the purpose of the analysis.

The 2001 R.M. Hardy Lecture: The limits of limit equilibrium analyses

2003 ◽  
Vol 40 (3) ◽  
pp. 643-660 ◽  
Author(s):  
John Krahn
Keyword(s):  
Finite Element ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Geotechnical Engineering ◽  
Software Tools ◽  
Great Promise ◽  
Engineering Practice ◽  
Stability Factor ◽  
Limit Equilibrium Methods

Limit equilibrium types of analysis have been in use in geotechnical engineering for a long time and are now used routinely in geotechnical engineering practice. Modern graphical software tools have made it possible to gain a much better understanding of the inner numerical details of the method. A closer look at the details reveals that the limit equilibrium method of slices has some serious limitations. The fundamental shortcoming of limit equilibrium methods, which only satisfy equations of statics, is that they do not consider strain and displacement compatibility. This limitation can be overcome by using finite element computed stresses inside a conventional limit equilibrium framework. From the finite element stresses both the total shear resistance and the total mobilized shear stress on a slip surface can be computed and used to determine the factor of safety. Software tools that make this feasible and practical are now available, and they hold great promise for advancing the technology of analyzing the stability of earth structures.Key words: limit equilibrium, stability, factor of safety, finite element, ground stresses, slip surface.

Analyses for the stability of potash tailings piles

1993 ◽  
Vol 30 (3) ◽  
pp. 491-505 ◽  
Author(s):  
Delwyn G. Fredlund ◽  
Zai Ming Zhang ◽  
Karen Macdonald
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Field Studies ◽  
Equilibrium Analysis ◽  
Limit Equilibrium Analysis ◽  
Dissipation Model ◽  
The Stability

The stability of potash tailings piles is investigated using a pore-water pressure generation and dissipation model together with a limit equilibrium analysis. It is found that a shallow toe failure mode is generally the most applicable and that the stability may be influenced by pore-water pressure migration below the pile. It is suggested that field studies would be useful in evaluating stability in the toe region of the pile. Key words : potash tailings, slope stability, pore pressure dissipation, solutioning.

Search of the Most Dangerous in Slide Slope Stability Analysis Based on Genetic Algorithm

2012 ◽  
Vol 166-169 ◽  
pp. 2535-2538
Author(s):  
Ke Wang ◽  
Chang Ming Wang ◽  
Fang Qi ◽  
Cen Cen Niu
Keyword(s):  
Genetic Algorithm ◽  
Stability Analysis ◽  
Slope Stability ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Evolutionary Process ◽  
Limit Equilibrium Method ◽  
Slope Stability Analysis ◽  
Equilibrium Method ◽  
The Stability

The traditional limit equilibrium method in the analysis of slope stability not only exists some subjective empirical hypothesis that can not meet the equilibrium of force and moment, but also ignores the effects of internal stress and strain on the slope stability. Furthermore, in the stability of the slope evaluation, limit equilibrium method relies too much on experience when hypothesizing the slope slip surface. So that it makes deviation on slope analysis and stability evaluation. This paper is based on simplified Bishop method used to establish the model of slope stability analysis. And it used genetic algorithms to solve the minimum safety factor and the most dangerous slip surface of slope. It was the arithmetic which simulates organisms genetic evolutionary process and it avoided the traditional methods falling into the local extreme value point easily and error propagation leading to convergence. The algorithm had advantages of higher accuracy, quick convergence and applicability. It showed that the genetic algorithm is accurate and reliable in the analysis of slope stability.

scholarly journals Brasília municipal solid waste landfill: a case study on flow and slope stability

2021 ◽  
Vol 44 (3) ◽  
pp. 1-13
Author(s):  
José Fernando Jucá ◽  
Alison Norberto ◽  
José Ivan Santos Júnior ◽  
Fernando Marinho
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Limit Equilibrium ◽  
Drainage System ◽  
Equilibrium Analysis ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Cause Of Failure ◽  
Leachate Level ◽  
The Stability

For geotechnical and environmental reasons, landfills are positioned above the regional water table and thus are formed in unsaturated conditions. This condition can be different if the drainage system and the rain regime of the site are such that they create a level of internal liquid in the landfill. During January and February 2019, excessive movements occurred in the slopes of the Brasília sanitary landfill. A geotechnical investigation indicated that the raised leachate level caused by the clogging of the drainage system contributed to the landfilled waste movements. The limit equilibrium analysis was used to predict the relationship between leachate level and slope stability. In order to understand the process that led to the rupture, flow and stability analysis by limit equilibrium were performed. The parameters associated with flow, water retention capacity, and shear strength were obtained based on literature evaluations. In addition, data from tests were used, which allowed to define more accurately the distribution of pore pressures of liquid that led to the failure. This study allowed to define the cause of failure and also to establish the role of the drainage system in maintaining the stability of the landfill. The studies indicated that although the gain of shear strength of landfill due to the unsaturated condition is negligible, the process of flow in unsaturated medium, associated with climatic aspects, are fundamental for a medium- and long-term analysis.

Anti-Sliding Stability Analysis of Saturated Rock Slope

2013 ◽  
Vol 405-408 ◽  
pp. 294-298
Author(s):  
Wei Luo ◽  
Jia Qi Chen ◽  
Lian Heng Zhao ◽  
Pan Cheng
Keyword(s):  
Rock Slope ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Seismic Load ◽  
Stability Factor ◽  
Surface Drag ◽  
Groundwater Levels ◽  
Saturated Rock ◽  
Sliding Stability ◽  
Water Saturated

Based on the assumption of the improved groundwater pressure distribution, the calculation expression of anti-sliding stability factor for typical water-saturated rock slope is deduced through limit equilibrium method. Considering the combined effect of slope overload, seismic load, anchoring effect, ice frost, slip surface drag force and slope groundwater pressure, the comparative analysis of typical rock slope sliding stability under waterless and saturated conditions shows that, the outflow joint blocking and the groundwater levels rising have obvious adverse effects on the anti-sliding stability of rock slope. Figures about the relationship of stability factors and geometric factors were drawn and the anti-sliding stability factor can be directly obtained from these figures. All would be the references for the similar engineering projects.

Study of the Three-Dimensional Global Limit Equilibrium Method Applied to the Stability of Rock Slope

2012 ◽  
Vol 249-250 ◽  
pp. 1099-1102
Author(s):  
Yi Sheng Huang ◽  
Jian Lin Li
Keyword(s):  
Rock Mass ◽  
Stability Analysis ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Limit State ◽  
Three Dimensional ◽  
Limit Equilibrium Method ◽  
Equilibrium Method ◽  
The Stability ◽  
Loose Rock

Amending the normal stress over the slip surface based on the stress field by numerical analysis, applying the three-dimensional global limit equilibrium method to the stability analysis of tension-slackened rock mass in the right bank of Yagen hydropower station. Stability analysis shows that if do not take any measures, the loose rock mass stability can cater to the Specification demand, but some small sliders is in the limit state under the water and earthquake condition, if use the cutting slope and unloading scheme, the whole loose rock mass and the all small sliders can meet the Specification standard stability requirements.

scholarly journals Examining the Effects of Suction and Nonlinear Strength Envelopes on the Stability of a High Plasticity Clay Slope

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 449
Author(s):  
Mengwei Xuan ◽  
Jack Montgomery ◽  
J. Brian Anderson
Keyword(s):  
Limit Equilibrium ◽  
Friction Angle ◽  
Stability Factor ◽  
High Plasticity ◽  
Slope Failures ◽  
Clay Deposits ◽  
Ring Shear ◽  
High Plasticity Clay ◽  
The Stability ◽  
Cut Slopes

Slope failures in high plasticity clay deposits are common occurrences in many parts of the world. In western and central Alabama, expansive Prairie clays are commonly found, and shallow slope failures have occurred in both fill and cut slopes containing these high plasticity clays. The objective of this study was to examine the effects of suction and the use of nonlinear strength envelopes on the embankment stability of a section of highway AL-5. The testing program consisted of fifteen ring shear tests performed using a Bromhead Ring Shear Device. The results of the tests were used to develop both linear and nonlinear fully softened and residual strength envelopes. The saturated strength envelopes are then used in a limit equilibrium slope stability analysis with and without the effects of suction. The results show stability (factor of safety >1) for all cases except the residual friction angle without suction. Given these results, large slope failures are unlikely to occur in this area, but surficial failures and deformations due to creep may be possible. These results demonstrate the importance of considering the effects of suction and nonlinear strength envelopes when examining the potential for shallow slope failures in high plasticity clays.

A Study on the Safety Criteria for Dike and Slope Exposed to Vibration

2011 ◽  
Vol 368-373 ◽  
pp. 2142-2146
Author(s):  
Yu Cheng Zhang ◽  
Guang Hua Yang ◽  
Hai Ying Hu
Keyword(s):  
Reduction Method ◽  
Limit Equilibrium ◽  
Safety Margin ◽  
Vibration Velocity ◽  
Inertia Force ◽  
Stability Factor ◽  
Free Vibration Frequency ◽  
Simple Consideration ◽  
Stability Of Slope ◽  
The Stability

Problems and flaws of existing safety criteria for vibration are reviewed. A simple consideration of particle vibration velocity cannot fully reflect the inherent law of effects of explosion earthquake on structures. Sometimes the occurrence of explosions exceeding the standard velocity for safety will not necessarily cause damage to structures and those below the standard velocity for safety may destroy structures. For this reason, the free vibration frequency of structures and the safety margin of the structure should be considered. Based on safe, practical and convenient conditions, that in respect of safety criteria for dike and slope exposed to vibration, two indicators, i.e., stability factor of dike and slope and vibration velocity of particle, can be used to determine the effect of vibration on them is proposed. That is to say, pseudo-static method is adopted to make vibration inertia force equivalent to a static force on slope bars and then strength reduction method or limit equilibrium method is used to calculate the safety factor, which can directly evaluate the stability of slope. In combination with the particle vibration velocity given in specifications, the safety of dike and slope can be determined. Lastly, specific engineering cases are used to validate the rationality of this criterion. This method can serve as a reference for similar projects

scholarly journals Evaluation of the stability of anchor-reinforced slopes

2005 ◽  
Vol 42 (5) ◽  
pp. 1342-1349 ◽  
Author(s):  
D Y Zhu ◽  
C F Lee ◽  
D H Chan ◽  
H D Jiang
Keyword(s):  
Stress Distribution ◽  
Normal Stress ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Load Factor ◽  
Normal Stress Distribution ◽  
Abrupt Changes ◽  
Reinforced Slopes ◽  
The Stability

The conventional methods of slices are commonly used for the analysis of slope stability. When anchor loads are involved, they are often treated as point loads, which may lead to abrupt changes in the normal stress distribution on the potential slip surface. As such abrupt changes are not reasonable and do not reflect reality in the field, an alternative approach based on the limit equilibrium principle is proposed for the evaluation of the stability of anchor-reinforced slopes. With this approach, the normal stress distribution over the slip surface before the application of the anchor (i.e., σ0) is computed by the conventional, rigorous methods of slices, and the normal stress on the slip surface purely induced by the anchor load (i.e., λpσp, where λp is the load factor) is taken as the analytical elastic stress distribution in an infinite wedge approximating the slope geometry, with the anchor load acting on the apex. Then the normal stress on the slip surface for the anchor-reinforced slope is assumed to be the linear combination of these two normal stresses involving two auxiliary unknowns, η1 and η2; that is, σ = η1σ0 + η2λpσp. Simultaneously solving the horizontal force, the vertical force, and the moment equilibrium equations for the sliding body leads to the explicit expression for the factor of safety (Fs)—or the load factor (λp), if the required factor of safety is prescribed. The reasonableness and advantages of the present method in comparison with the conventional procedures are demonstrated with two illustrative examples. The proposed procedure can be readily applied to designs of excavated slopes or remediation of landslides with steel anchors or prestressed cables, as well as with soil nails or geotextile reinforcements.Key words: slopes, factor of safety, anchors, limit equilibrium method.

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