scholarly journals Effects of Bonded Tyres on Leachate Recirculation of Bioreactor Landfills

2017 ◽  
Vol 11 (1) ◽  
pp. 552-562 ◽  
Author(s):  
Huijie Zhang ◽  
Jie Heng ◽  
Dongsheng Jeng ◽  
Haixia Xu

Introduction: In bioreactor landfills, leachate recirculation significantly influences the process of stabilization and the stability of slope. Method: To speed up the leachate recirculation and reduce its adverse impact on slope stability, this paper proposes a new method which constructs a spatial net consisted of bonded whole tyres in the municipal waste during landfilling. Results and Conclusion: In this study, a numerical two-permeability flow model was used to investigate the effects of tyres embedding on the outflow rate of leachate injection. Furthermore, it was coupled with momentum balance equations to determine the local factor of safety of slope stability. The established model was applied to a simplified bioreactor landfill. The simulation results demonstrated that the tyre net can accelerate the rate of leachate injection and contribute to distribute the liquid more uniformly. Meanwhile, the slope stability was improved due to the enforcement of waste in the presence of tyres.

2020 ◽  
Vol 4 (3) ◽  
pp. 196
Author(s):  
Dhrubo Haque ◽  
Md Isteak Reza

This paper has aimed to investigate the slope stability for various conditions like embankment geometry, water level and soil property. The analysis has been performed by using the XSTABL program for different slope heights, slope angles and flood conditions with a fixed soil cohesion value. Since the rapid drawdown is the worst case for a particular embankment therefore, the analysis has been further performed with different cohesion values. From this investigation it has been noticed that the increase of cohesion of soil can increase the stability to a great extent. All the analysises have been performed for twenty bore logs. It has been found that the underlying soil affects the stability of slope as the failure surface intersects the soil of this region. It has been also observed that the loose, liquefiable sandy soil decreases the stability while the stiff soil with sufficient cohesion value stabilizes the slope of embankment.  This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited. 


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.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shi-Jin Feng ◽  
Shao-Jie Wu ◽  
Wen-Ding Fu ◽  
Qi-Teng Zheng ◽  
Xiao-Lei Zhang

AbstractDuring the operation of landfills, leachate recirculation and aeration are widely applied to accelerate the waste stabilization process. However, these strategies may induce high pore pressures in waste, thereby affecting the stability of the landfill slope. Therefore, a three-dimensional numerical analysis for landfill slope stability during leachate recirculation and aeration is performed in this study using strength reduction method. The bio-hydro coupled processes of waste are simulated by a previously reported landfill coupled model programmed on the open-source platform OpenFOAM and then incorporated into the slope stability analysis. The results show that both increasing the injection pressure for leachate recirculation and maximum anaerobic biodegradation rate will reduce the factor of safety (FS) of the landfill slope maximally by 0.32 and 0.62, respectively, due to increased pore pressures. The ignorance of both waste biodegradation and gas flow will overestimate the slope stability of an anaerobic bioreactor landfill by about 20–50%, especially when the landfilled waste is easily degradable. The FS value of an aerobic bioreactor landfill slope will show a significant reduction (maximally by 53% in this study) when the aeration pressure exceeds a critical value and this value is termed as the safe aeration pressure. This study then proposes a relationship between the safe aeration pressure and the location of the air injection screen (i.e., the horizontal distance between the top of the injection screen and the slope surface) to avoid landfill slope failure during aeration. The findings of this study can provide insights for engineers to have a better understanding of the slope stability of a bioreactor landfill and to design and control the leachate recirculation and aeration systems in landfills.


2012 ◽  
Vol 170-173 ◽  
pp. 3186-3189 ◽  
Author(s):  
Li Wang ◽  
Cui Ran Liu

There is suction in unsaturated soil. This is the most obvious difference between unsaturated soil and saturated soil. It is very difficult to measure it, so research has always been done without account of the influences of matric suction of unsaturated soil. In this paper, based on the test result of engineering characteristics of unsaturated soil from Yellow River Embankments, the stability of slope of Yellow River Embankments is analyzed using ultimate equilibrium method and the influencing rule of matric suction on slope is advanced.


2014 ◽  
Vol 484-485 ◽  
pp. 599-603
Author(s):  
Guang Ming Bao ◽  
Juan Chang ◽  
Zhi Gang Liu

This paper uses the simulation technology of computer numerical simulation, combined with the GAMBIT numerical modeling software and ANSYS structure analysis software, we carry out an in-depth research and analysis on the stability of engineering simulation, at the same times establish the mathematical model of ANSYS numerical simulation displacement stability and design the ANSYS command stream program algorithm. Finally, this paper uses the open-pit to underground mining slope stability as an example, to verify the reliability of the model and algorithm. Through the numerical simulation, we get the displacement of slope in the Y direction and Z direction. In the Y direction, the maximum displacement is 0m, the negative maximum displacement is 5.88m and displacement is relatively large; in the Z direction, the maximum displacement is 1.32M, the negative maximum displacement is 1.08M and the stability of slope is different in different position. The numerical simulation provides the theory reference for the safety of mining engineering.


2021 ◽  
Author(s):  
Fentahun Ayalneh Mekonnen

Slope failures are among the common geo-environmental natural hazards in the hilly and mountainous terrain of the world. Specially it is the major difficulty for the development of construction as it causes considerable damage on the infrastructure, human life and property. Different causes of slope failure and stabilization methods are proposed by different scholars. In this study the performance of geometric modification in slope stability was investigated using numerical method. The study uses slope height, slope angle and slope profile i.e. single slope, multi slope and bench slope as a governing parameter in the performance evaluation of geometric modification on the slope stability. The evaluation was conducted on a newly constructed road cut slope using a finite element based plaxis software. The result from performance evaluation of slope profiles show that geometric modification provides better and economical slope stability. The stability of slope decreases with increase in slope height and slope angle leading to an uneconomical design of high slopes in a single slope profile. However, the use of benching improves the stability of cut slope (i.e. the use of 2 m and 3 m bench improves the factor of safety by 7.5% and 12% from single slope profile). The method is more effective in steep slopes. Similarly, the use of a multi slope profile improves the stability of slope in stratified soil with varied strength. The performance is more significant when it is used in combination with benches. The study also provides comparison of slope profiles based on different criteria’s and recommend the selection profile based on site-specific considerations.


2012 ◽  
Vol 204-208 ◽  
pp. 312-315
Author(s):  
Zeng Rong Liu ◽  
Shao Feng Luo

Aiming at researching on stability of high filling slope effected by precipitation duration. Transient saturated-unsaturated seepage method and slope stability finite element method is combined in this paper. Vadose field of slope is simulated in different precipitation duration condition. On the basis of vadose field author analyses the stability of slope effected by precipitation duration. The research results indicate that change of the pore water pressure is mainly concentrated in the position where the water level changes in the process of precipitation. After the precipitation pore water pressure gradually dissipates. Precipitation duration has great effect on the slope stability. With the precipitation duration increases the slope safety coefficient decreases. The slope safety coefficient decreases in the process of precipitation, but after precipitation, it increases gradually and eventually be more stable. The longer the precipitation duration is, the longer time that the safety coefficient reaches the ultimate stability required.


2014 ◽  
Vol 580-583 ◽  
pp. 755-759
Author(s):  
Shi Guo Sun ◽  
Ya Nan Yi ◽  
Qin Huan Cui ◽  
Lu Jin

The optimum design of final highwall is a multivariable and complex technical problem that every change in any factor will influence the stable state. Based on the history-case, this paper applied the critical sliding field to search the critical slip and evaluate the stability of slope with different geometric forms. Comprehensively compared the global and local slope stability and its economic benefits, finally achieved the optimum design of final highwall.


2013 ◽  
Vol 405-408 ◽  
pp. 1445-1448
Author(s):  
Ting Kai Nian ◽  
Bo Liu ◽  
Ping Yin

The effects of ocean waves on the stability of seafloor slopes are of great importance in marine environment. The stability of a seafloor slope considering wave-induced pressure is analyzed using the kinematic approach of limit analysis combined with a strength reduction technique. A seafloor slope without waves is considered first. Furthermore, waved-induced pressure is considered to act on the surface of slope as an external load to analyze the effects on the stability of slope by waves. The results show that the adverse effect of waves on slope stability increases with an increase of the wave height as well as a decrease of the water depth.


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