scholarly journals Parametric Analysis of Slope Stability for River Embankment

2020 ◽  
Vol 4 (3) ◽  
pp. 196
Author(s):  
Dhrubo Haque ◽  
Md Isteak Reza
Keyword(s):  
Slope Stability ◽  
Soil Property ◽  
Failure Surface ◽  
Worst Case ◽  
Creative Commons ◽  
Stability Of Slope ◽  
The Stability ◽  
Underlying Soil ◽  
Open Access Article ◽  
Stiff Soil

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. 

scholarly journals An Initial Value Problem Involving Caputo-Hadamard Fractional Derivative: The Extremal Solutions and Stabilization

2020 ◽  
Vol 4 (2) ◽  
pp. 149
Author(s):  
O'Regan Donal ◽  
Ngo Van Hoa
Keyword(s):  
Open Access ◽  
Fractional Derivative ◽  
Original Work ◽  
Extremal Solutions ◽  
Sufficient Condition ◽  
Initial Value ◽  
Creative Commons ◽  
Fractional Differential ◽  
The Stability ◽  
Open Access Article

In this paper, the existence of extremal solutions of Caputo-Hadamard-type fractional differential equations (CHFDEs) with order $\alpha \in (1,2)$ is established by employing the method of lower and upper solutions. Moreover, sufficient condition that ensures the stability of a class of CHFDE is also provided. Some examples are given to illustrate our main results. 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.

Stability Analysis of High Filling Slope Affected by Precipitation Intensity

2012 ◽  
Vol 170-173 ◽  
pp. 1174-1178 ◽  
Author(s):  
Wen Tao Wang ◽  
Tao Song ◽  
Zeng Rong Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Slope Stability ◽  
Precipitation Intensity ◽  
Safety Coefficient ◽  
Stability Of Slope ◽  
Seepage Theory ◽  
The Stability ◽  
Unsaturated Seepage ◽  
Element Method

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.

Fuzzy Reliability Analysis of Geocell Protective Slope Stability

2012 ◽  
Vol 166-169 ◽  
pp. 1917-1921 ◽  
Author(s):  
Guang Yue Wang ◽  
Yan Han
Keyword(s):  
Probability Density Function ◽  
Failure Probability ◽  
Soil Property ◽  
Structural Performance ◽  
Reliability Model ◽  
Fuzzy Reliability ◽  
Performance Function ◽  
Stability Of Slope ◽  
The Stability ◽  
Calculated Model

In order to analyze the uncertainty existing in the stability of slope with geocell, the fuzziness of soil property parameters should be considered. In this paper, probability density function of structural performance function and membership function of the stability of slope with geocell was determined. The fuzzy reliability model of the stability of slope with geocell was established. The fuzzy reliability and fuzzy failure probability of slope with geocell instability were calculated, and the practicability of the calculated model was verified.

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
Keyword(s):  
Slope Stability ◽  
Momentum Balance ◽  
Bioreactor Landfill ◽  
Bioreactor Landfills ◽  
Leachate Recirculation ◽  
Local Factor ◽  
Outflow Rate ◽  
Speed Up ◽  
Stability Of Slope ◽  
The Stability

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.

Duration of respiratory sample stability at -80ºC for SARS-CoV-2 PCR

2021 ◽  
Vol 38 (ICON-2022) ◽  
Author(s):  
Javeria Aijaz ◽  
Fouzia Naseer ◽  
Maqboola Dojki ◽  
Saba Jamal
Keyword(s):  
Standard Laboratory ◽  
Respiratory Sample ◽  
Repeat Testing ◽  
Creative Commons ◽  
Sample Stability ◽  
Duration Of Storage ◽  
Consistent Increase ◽  
The Stability ◽  
Respiratory Specimens ◽  
Open Access Article

Objective: To determine the stability of respiratory samples for SARS-CoV-2 PCR at standard laboratory ultra-freezer temperatures (-80°C). Methods: Five hundred and sixty-five archived, SARS-CoV-2 PCR positive patient specimens received at the Pathology Department of the Indus Hospital & Health Network between January 2021 and June 2021 were retested in June 2021. Samples had been stored at -70°C or below throughout this duration. Sample integrity following storage was assessed as the percentage of samples with reproducible results, and as consistency of cycle threshold (Ct) values between the original testing and the repeat testing. Results: Of the 565 samples evaluated in this study, 86% gave reproducible results upon retesting. However, there was no correlation between the duration of storage and result reproducibility, though the majority (69% for PCR Target-I and 78% for PCR Target-II respectively) of non-reproducible results had Ct values above 30. Similarly, there was a consistent increase of Ct values upon storage at ultra-freezer temperatures, though the effect again was more contingent upon freezing the sample in the ultra-freezer rather than the duration of storage. Conclusion: SARS-CoV-2 positive respiratory specimens for PCR can be stored for up to six months at -70°C or below without loss of sample integrity, though there is some loss of PCR-detected viral targets as evidenced by an immediate increased in the PCR-generated Ct values. In addition, samples with initial Ct values above 30 are more likely to give non-reproducible results. doi: https://doi.org/10.12669/pjms.38.ICON-2022.5777 How to cite this:Aijaz J, Naseer F, Dojki M, Jamal S. Duration of respiratory sample stability at -80ºC for SARS-CoV-2 PCR. Pak J Med Sci. 2022;38(2):393-398. doi: https://doi.org/10.12669/pjms.38.ICON-2022.5777 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Analysis of the Influences of Matric Suction of Unsaturated Soil on the Slope Stability

2012 ◽  
Vol 170-173 ◽  
pp. 3186-3189 ◽  
Author(s):  
Li Wang ◽  
Cui Ran Liu
Keyword(s):  
Slope Stability ◽  
Unsaturated Soil ◽  
Yellow River ◽  
Matric Suction ◽  
Saturated Soil ◽  
Equilibrium Method ◽  
Stability Of Slope ◽  
Ultimate Equilibrium ◽  
The Stability ◽  
Test Result

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.

Analysis of the Open-Pit to Underground Mining Slope Stability

2014 ◽  
Vol 484-485 ◽  
pp. 599-603
Author(s):  
Guang Ming Bao ◽  
Juan Chang ◽  
Zhi Gang Liu
Keyword(s):  
Numerical Simulation ◽  
Slope Stability ◽  
Underground Mining ◽  
Open Pit ◽  
Maximum Displacement ◽  
Modeling Software ◽  
Stability Of Slope ◽  
Computer Numerical Simulation ◽  
The Stability ◽  
Mining Slope

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.

scholarly journals Performance Evaluation of Geometric Modification on the Stability of Road Cut Slope Using FE Based Plaxis Software

2021 ◽  
Author(s):  
Fentahun Ayalneh Mekonnen
Keyword(s):  
Performance Evaluation ◽  
Slope Stability ◽  
Slope Failure ◽  
Human Life ◽  
Slope Angle ◽  
Cut Slope ◽  
Governing Parameter ◽  
Stability Of Slope ◽  
The Stability ◽  
Steep Slopes

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.

Stability Analysis of High Filling Slope Effected by Precipitation Duration

2012 ◽  
Vol 204-208 ◽  
pp. 312-315
Author(s):  
Zeng Rong Liu ◽  
Shao Feng Luo
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Safety Coefficient ◽  
Stability Of Slope ◽  
The Stability ◽  
Duration Condition ◽  
Unsaturated Seepage ◽  
Slope Safety

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.

The Optimum Design of Slope Angle Based on Critical Sliding Field

2014 ◽  
Vol 580-583 ◽  
pp. 755-759
Author(s):  
Shi Guo Sun ◽  
Ya Nan Yi ◽  
Qin Huan Cui ◽  
Lu Jin
Keyword(s):  
Slope Stability ◽  
Optimum Design ◽  
Technical Problem ◽  
Slope Angle ◽  
Stable State ◽  
Economic Benefits ◽  
Local Slope ◽  
Stability Of Slope ◽  
The Stability ◽  
Global And Local

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.

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