scholarly journals Slope Stability of Landfill with Waste Degradation

Nowadays, a large amount of municipal solid waste (MSW) is generated due to the rapid urbanisation in developing countries leads to the demand for larger and higher capacity landfills. Bioreactor landfill technology has been introduced to accelerate the stability of landfill and to solve the issue of limited landfill area. However, the accelerated degradation of the refuse in bioreactor landfills also considerably changes the geotechnical characteristics of the waste in the landfill and thereby increases the concern for waste stability. Hence, this study aims to analyse the stability of both conventional and bioreactor landfill slope with the effects of waste degradation. Finite element method has been used in the slope stability analysis and the stability is presented by the factor of safety. The objectives of this study are i) to determine and assess the main parameter which influences the stability of the waste slope, ii) to determine the effects of waste degradation to the waste properties and iii) to obtain the factor of safety of the landfill slope using numerical analysis by finite element method. From the literature review, it is found that slope stability of a landfill mainly depends on the geotechnical properties of waste, such as moisture content, unit weight, shear strength parameters and hydraulic conductivity of waste. After the degradation process, engineering properties of field refuse are affected which includes the increased pore-water pressure and unit weight, decreased strength and lower hydraulic conductivity. Based on the analysis of conventional landfill slope stability by using Plaxis software, slope ratio of 1:3, 1:4 and 1:5 calculated safe with 1.69, 2.3 and 2.8 whereas the analysis of bioreactor landfill slope stability calculated safe only for slope ratio of 1:4 and 1:5 with 1.60 and 1.97. Moreover, the factor of safety for steeper slopes is lower and vice versa. From the parametric analysis, it is found that the full height of slope and unit weight of waste input affect the result analysis. This study is significant to evaluate the landfill slope stability with the effects of waste degradation and to ensure both conventional and bioreactor landfill slope stability for long periods.

2016 ◽  
Vol 857 ◽  
pp. 555-559 ◽  
Author(s):  
Zuhayr Md Ghazaly ◽  
Mustaqqim Abdul Rahim ◽  
Kok Alfred Chee Jee ◽  
Nur Fitriah Isa ◽  
Liyana Ahmad Sofri

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.


2012 ◽  
Vol 170-173 ◽  
pp. 1174-1178 ◽  
Author(s):  
Wen Tao Wang ◽  
Tao Song ◽  
Zeng Rong Liu

Aiming at researching on stability of slope affected by precipitation intensity, transient saturated-unsaturated seepage finite element method and slope stability finite element method are combined in this paper. Vadose field of slope is simulated in different precipitation intensity. Based on vadose field, the writers analyzed the stability of slope affected by precipitation intensity. The research results indicate that water is brought together in the interface first. Then the water level moves toward up and down respectively from the both sides of the interface. On the basis of saturated-unsaturated seepage theory, precipitation intensity has little effect on the slope stability in the first 6 hours after precipitation. After that, slope safety coefficient is relatively high when precipitation intensity is smaller, and vice versa.


1980 ◽  
Vol 17 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Jean Lafleur ◽  
Guy Lefebvre

Slope stability analyses in terms of effective stresses are most often based on hypothetical conditions of pore pressure. It is generally assumed that the flow occurs parallel to the slope or even that the conditions are hydrostatic. In fact, in situ measurements tend to show that the real situation could significantly deviate from these approximations due to geologic conditions. The influence of various geometric and stratigraphic factors on the groundwater regime and on the stability of slopes was studied with the finite-element method. To illustrate the parametric study, experimental evaluations of the flow patterns are presented at four sites. The stratigraphy and permeability measurements combined with the finite-element method enabled a complete flow net to be drawn and although some hypotheses had to be formulated with regards to the underlying aquifer recharge or permeability anisotropy, reasonable agreement was found between simulated and measured piezometric heads.


Author(s):  
Shalaho Dina Devy ◽  
Pretty Permatasari Hutahayan

The stability of open pit slopes in Biangan district, West Kutai Regency, East Kalimantan Province, is greatly influenced by groundwater conditions. The existence of groundwater reduces the shear strength of the materials which causes a decrease in the stability value of pit slopes. The main objective of this study is to assess the impact of groundwater on the stability of the low wall and high wall pit mining. Groundwater modeling is used to determine the prediction of groundwater level on the pit slope which determines the value of the slope stability. Slope stability analysis in this study was performed using the Finite Element Method, producing output in the form of strain zones, deformation and displacement values. Therefore, the Strength Reduction Factor (SRF) approach was used, which is a gradual reduction of shear strength until the values of cohesion and friction angles reach minimums and the slopes are at a critical state. Groundwater modeling results indicate that groundwater flows to the Biangan river with hydraulic heads between 76 and 108 meters above sea level. Based on the analysis using the Finite Element Method, the stability values of the pit slopes, which are influenced by groundwater, are 0.65 on the low wall and 1.40 on the high wall. The total displacements are 0.019 meters on the low wall and 0.002 meters on the high wall.  The impact of groundwater on the slope is an increase in the slope load. This increases the materials’ thrust and reduces the shear strength of the materials which reduces the rock mass that can function as a water seepage path. Thus, the recommendation for low wall pit construction is a safety factor of 7.79 with a total displacement of 0.020 meters.


2011 ◽  
Vol 462-463 ◽  
pp. 319-324
Author(s):  
Ahmad Anwar Mohd Yunus ◽  
Anuar Kasa ◽  
Zamri Chik ◽  
Taha Mohd Raihan

The objective of this research is to study the relationships between the stability of earth dam and its soil strength parameters. The soil strength parameters include cohesion, unit weight of soil and angle of friction. GeoStudio, commercially available software, was used to obtain the overall factor of safety using limit equilibrium method (LEM) and finite element method (FEM). Tables to show the relationships among soil strength parameters for factor of safety 1.0 and 1.5 are presented in this paper.


Author(s):  
Jian-Min Zhang ◽  
Jianhong Zhang ◽  
Gang Wang ◽  
Yang Chen

This paper presents a study of stability of a trial quay wall of large diameter cylinders at the Yangshan Port, China. Stability analysis of the quay wall during construction is carried out using finite element method. The results of the analysis indicate that a turnover failure is potential for the single cylinder subjected to a five year design wave action. The case when the cylinder is empty is the critical situation during construction. Filling the cylinder right after the installation is an effective way to increase the stability. After the quay wall has been formed by joining the single cylinders, the safety against overturning is reevaluated. The factor of safety of the quay wall is assessed to be 1.5 under a fifty year design wave action.


2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.


1983 ◽  
Vol 20 (4) ◽  
pp. 661-672 ◽  
Author(s):  
R. K. H. Ching ◽  
D. G. Fredlund

Several commonly encountered problems associated with the limit equilibrium methods of slices are discussed. These problems are primarily related to the assumptions used to render the inherently indeterminate analysis determinate. When these problems occur in the stability computations, unreasonable solutions are often obtained. It appears that problems occur mainly in situations where the assumption to render the analysis determinate seriously departs from realistic soil conditions. These problems should not, in general, discourage the use of the method of slices. Example problems are presented to illustrate these difficulties and suggestions are proposed to resolve these problems. Keywords: slope stability, limit equilibrium, method of slices, factor of safety, side force function.


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