Upper Bound Analysis on the Stability of Cracked Slopes at Tunnel Entrance Subjected to Pore Water Pressure

Abstract Soil pore water pressure analysis is crucial for understanding landslide initiation and prediction. However, field-scale transient pore water pressure measurements are complex. This study investigates the integrated application of simulation models (HYDRUS-2D/3D and GeoStudio–Slope/W) to analyze pore water pressure-induced landslides. The proposed methodology is illustrated and validated using a case study (landslide in India, 2018). Model simulated pore water pressure was correlated with the stability of hillslope, and simulation results were found to be co-aligned with the actual landslide that occurred in 2018. Simulations were carried out for natural and modified hill slope geometry in the study area. The volume of water in the hill slope, temporal and spatial evolution of pore water pressure, and factor of safety were analysed. Results indicated higher stability in natural hillslope (factor of safety of 1.243) compared to modified hill slope (factor of safety of 0.946) despite a higher pore water pressure in the natural hillslope. The study demonstrates the integrated applicability of the physics-based models in analyzing the stability of hill slopes under varying pore water pressure and hill slope geometry and its accuracy in predicting future landslides.

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Unsaturated Seepage and Fluid-Solid Coupling Analysis of Rainfall Infiltration of Slope

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.255-260.3488 ◽

2011 ◽

Vol 255-260 ◽

pp. 3488-3492

Author(s):

Bao Lin Xiong ◽

Jing Song Tang ◽

Chun Jiao Lu

Keyword(s):

Pore Water ◽

Unsaturated Flow ◽

Pore Water Pressure ◽

Water Pressure ◽

Rainfall Infiltration ◽

Medium Permeability ◽

Stability Of Slope ◽

Transient Seepage ◽

The Stability ◽

Unsaturated Seepage

Rainfall is one of the main factors that influence the stability of slope. Rainfall infiltration will cause soil saturation changing and further influence pore water pressure and medium permeability coefficient. Based on porous media saturation-unsaturated flow theory, the slope transient seepage field is simulated under the conditions of rainfall infiltration. It is shown that change of pore water pressure in slope soil lag behind relative changes in rainfall conditions. As the rainfall infiltrate, unsaturated zone in top half of slope become diminution, the soil suction and shear strength reduce, so stabilization of soil slope is reduced.

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New technique for predicting the pore water pressure and evaluating the stability of rock-fill dam during impounding

Journal of Groundwater Hydrology ◽

10.5917/jagh1987.49.3 ◽

2007 ◽

Vol 49 (1) ◽

pp. 3-15

Author(s):

Yasuo YANAKA ◽

Akira TAKAHASHI ◽

Yoshinobu HOS H INO ◽

Tomokazu SUZUKI ◽

Makoto NISHIGAKI ◽

...

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

New Technique ◽

Rock Fill ◽

The Stability

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Analyses for the stability of potash tailings piles

Canadian Geotechnical Journal ◽

10.1139/t93-042 ◽

1993 ◽

Vol 30 (3) ◽

pp. 491-505 ◽

Cited By ~ 1

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.

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Influence of Layer Transition Zone on Rainfall-Induced Instability of Multilayered Slope

Lithosphere ◽

10.2113/2021/2277284 ◽

2021 ◽

Vol 2021 (Special 4) ◽

Author(s):

Zhi Dou ◽

Yimin Liu ◽

Xueyi Zhang ◽

Yashan Wang ◽

Zhou Chen ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Transition Zone ◽

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Layer Transition ◽

Infiltration Process ◽

Local Factor ◽

The Stability ◽

Different Thickness

Abstract Although numerous studies have been paid much attention to rainfall-induced instability of multilayered slopes, the interface between layers is generally considered to be “zero thickness”, and the layer transition zone between layers is neglected. In this study, the influence of the layer transition zone on the rainfall-induced instability of multilayered slope was investigated. A model was developed to simulate the rainfall infiltration process, the distribution of pore water pressure, and the stability of multilayered slope by coupling the unsaturated seepage model and the slope stability analysis method. Based on the analysis of the multilayered slopes with the different thickness ratios of the layer transition zone, a method for determining the critical thickness of the layer transition zone was proposed. The results showed that the layer transition zone had a significant influence on the stability of multilayered slope. It was found that the presence of the layer transition zone in the multilayered slope reduced the hydraulic conductivity of the slope and increased the rate of formation of transient saturated zone, which contributed to excess pore water pressure at the toe of the slope. The analysis of the local factor of safety (LFS) showed that when the thickness ratios of the layer transition zone were between 2.5% and 5%, the corresponding hydraulic conductivity of the slope decreased by 1%-2.5% and the maximum failure area of the slope during the rainfall was 25% of the slope. Our study highlighted the importance of the layer transition zone for the rainfall-induced instability of the multilayered slope.

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An Analytical Continuous Upper Bound Limit Analysis of Pore Water Effect on the Tail Stability of Underwater Shield Tunnels during Construction

E3S Web of Conferences ◽

10.1051/e3sconf/202014301015 ◽

2020 ◽

Vol 143 ◽

pp. 01015

Author(s):

Wenjie Song ◽

Yanyong Xiang

Keyword(s):

Pore Water ◽

Upper Bound ◽

Limit Analysis ◽

Pore Water Pressure ◽

Water Pressure ◽

Ground Surface ◽

Support Pressure ◽

Tunnel Support ◽

Transverse Stability ◽

Upper Bound Limit Analysis

An analytical continuous upper bound limit analysis is developed to analyse the effects of seepage on the transverse stability of underwater shield tunnels. The approach is based on an analytical continuous upper bound limit analysis method for cohesive-frictional soils. It employs the complex variables solution of the displacement field due to tunnel deformation and movement, and the analytical solution of the pore water pressure field for steady state seepage due to pore water influx at the tunnel perimeter. The most critical slip line position and the minimum required tunnel support pressure are determined by using a particle swarm optimization scheme for various generic situations. The method is verified via finite element simulation and comparison with the solution from using rigid block upper bound limit analysis. The parametric analysis revealed among other things that both the infimum of the necessary tunnel support pressure and the most critical plastic zone increase when the hydraulic head at the ground surface increases, but decrease when the tunnel influx increases due to the fact that pore water pressure at the tunnel perimeter decreases with the tunnel influx.

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Numerical Analysis of an Upstream Tailings Dam Subjected to Pond Filling Rates

Applied Sciences ◽

10.3390/app11136044 ◽

2021 ◽

Vol 11 (13) ◽

pp. 6044

Author(s):

Tan Manh Do ◽

Jan Laue ◽

Hans Mattsson ◽

Qi Jia

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Tailings Dam ◽

Filling Rate ◽

Excess Pore Water Pressure ◽

Finite Element Software ◽

Consolidation Phase ◽

The Stability ◽

Excess Pore

One of the challenges in upstream tailings dam projects is to ensure the allowable rate of deposition of tailings in the pond (i.e., pond filling rate) while maintaining the stability of the dam. This is due to the fact that an upstream tailings dam is constructed by placing dikes on top of previously deposited soft tailings, which could lead to a decrease in dam stability because of the build-up of excess pore water pressure. The main purpose of this work is to investigate the effects of pond filling rates on excess pore water pressure and the stability of an upstream tailings dam by a numerical study. A finite element software was used to simulate the time-dependent pond filling process and staged dam construction under various pond filling rates. As a result, excess pore water pressure increased in each raising phase and decreased in the subsequent consolidation phase. However, some of the excess pore water pressure remained after every consolidation phase (i.e., the build-up of excess pore water pressure), which could lead to a potentially critical situation in the stability of the dam. In addition, the remaining excess pore water pressure varied depending on the pond filling rates, being larger for high filling rates and smaller for low filling rates. It is believed that the approach used in this study could be a guide for dam owners to keep a sufficiently high pond filling rate but still ensure the desirable stability of an upstream tailings dam.

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Three-Dimensional Upper Bound Limit Analysis on the Collapse of Shallow Soil Tunnels considering Roof Stratification and Pore Water Pressure

Mathematical Problems in Engineering ◽

10.1155/2019/8164702 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Hong-Tao Wang ◽

Ping Liu ◽

Chi Liu ◽

Xin Zhang ◽

Yong Yang ◽

...

Keyword(s):

Pore Water ◽

Upper Bound ◽

Pore Water Pressure ◽

Water Pressure ◽

Nonlinear Coefficient ◽

Soil Layer ◽

Three Dimensional ◽

Support Pressure ◽

Flow Rule ◽

Soil Cohesion

Based on the plastic upper bound theorem, a three-dimensional kinematically admissible velocity field is constructed for the collapse of the soil masses above a shallow tunnel. In this field, this paper considers the influences of the roof stratification, pore water pressure, ground overload, and support pressure. This study deduced the upper bound solutions of the weight of the collapsed soil masses and the corresponding collapse surfaces by utilizing the nonlinear failure criterion, associated flow rule, and variation principle. Furthermore, we verified the validity of the proposed method in this paper by comparing this research with the existing work and numerical simulation results. This study obtains the influence laws of varying parameters on the area and weight of the collapsed soil masses. The results reveal that the area and weight of the collapsed soil masses increase with increasing support pressure and soil cohesion, but decrease with increasing thickness of the upper soil layer, nonlinear coefficient, pore water pressure, and ground overload. Among them, the roof stratification, pore water pressure, soil cohesion, and nonlinear coefficient have a significant influence on tunnel collapse, which should be given special consideration in engineering design.

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