Analysis on the Impact of Expansive Soil Slope Stability by Rainfall Infiltration

2018 ◽  
Author(s):  
Huang Zhi-Fang
Keyword(s):  
Slope Stability ◽  
Expansive Soil ◽  
Rainfall Infiltration ◽  
Soil Slope ◽  
The Impact

scholarly journals Performance estimation of a shallow foundation on an unsaturated expansive soil slope subjected to rainfall infiltration

2021 ◽  
Vol 337 ◽  
pp. 03009
Author(s):  
Mengxi Tan ◽  
Sai K. Vanapalli
Keyword(s):  
Slope Stability ◽  
Limit Equilibrium ◽  
Expansive Soil ◽  
Rainfall Infiltration ◽  
Performance Estimation ◽  
Shallow Foundation ◽  
Water Infiltration ◽  
Rational Approach ◽  
Soil Slope ◽  
Unsaturated Expansive Soil

In the last two decades, there has been a significant increase in infrastructure development on slopes of hilly regions of the world, due to population growth. There are many infrastructures on unsaturated expansive slopes, especially in semi-arid and arid regions. Rainfall infiltration is one of the major factors that contributes to the slope and infrastructure foundations failures on hilly slopes with unsaturated expansive soils. In the current study, a rational approach is proposed considering the combined influence of the foundation-slope behavior based on the principles of unsaturated soil mechanics. This is achieved by a novel numerical modelling approach using the commercial software Geo-studio to investigate the performance of strip foundation located on the top of the unsaturated expansive soil slope subjected to various rainfall infiltration conditions. Hydro-mechanical coupling analysis is conducted to evaluate the rainfall water infiltration influence combined with slope stability analysis using limit equilibrium method. Comparisons are made between both the foundation bearing capacity, slope stability before and after rainfall water infiltration. Different failure mechanisms of the foundation and slope system are presented with and without foundation loading for various rainfall scenarios. Results summarized in this paper are helpful for the geotechnical engineers for understanding the performance of shallow foundations on unsaturated expansive soil slopes considering the influence of rainfall infiltration conditions.

scholarly journals Stability of Soil Cutting and Side Slope Based on Stress Route Theory

2015 ◽  
Vol 2 ◽  
pp. 1
Author(s):  
Zhaohong Ji
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Effective Stress ◽  
Analytical Method ◽  
Soil Slope ◽  
Safety Coefficient ◽  
Side Slope ◽  
Stress Changes ◽  
Soil Cutting ◽  
The Impact

<p>The stress route analytical method compensates for the limitation of traditional soil slope stability analytical method. Since it disregards the impact of effective stress route on the stress status and anti-shear strength of soil slope, it maps out the soil stress route drawing in the excavation process, and marks the anti-shear strength and shear stress changes under various conditions of soil. It causes the changes of the safety coefficient rules in the excavation of soil slope and affects the excavation stability of soil cutting and side slope. The result reveals: (1) The main analytical method of side slope stability which covers both the limit balance method and finite unit method fails to consider the impact of effective stress route on the existing stress status and anti-shear strength of soil slope; the stress route analytical method is able to overcome this limitation to a certain degree. (2) The stress route theory is adopted for analysis, in which, it can projected the whole stress of typical and most dangerous area of the slope, able to analyse the anti-shear strength of soil in a real-time manner, manage to express the safety coefficient changes in the stress route drawing and provides a selection of a suitable excavation plan by contrast. (3) In the overall excavation, the slope toe suffers from obvious stress concentration which expands to the surrounding areas and inconvenient for the side slope stability in the excavation.</p>

Effects of Airflow Induced by Rainfall Infiltration on Unsaturated Soil Slope Stability

2015 ◽  
Vol 107 (3) ◽  
pp. 821-841 ◽  
Author(s):  
Dong-mei Sun ◽  
Yong-ge Zang ◽  
Stephan Semprich
Keyword(s):  
Slope Stability ◽  
Unsaturated Soil ◽  
Rainfall Infiltration ◽  
Soil Slope

scholarly journals Sensibility Analysis of the Hydraulic Conductivity Anisotropy on Seepage and Stability of Sandy and Clayey Slope

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 277 ◽  
Author(s):  
Shuyang Yu ◽  
Xuhua Ren ◽  
Jixun Zhang ◽  
Haijun Wang ◽  
Zhitao Zhang
Keyword(s):  
Slope Stability ◽  
Sandy Soil ◽  
Clayey Soil ◽  
Rainfall Infiltration ◽  
Anisotropy Ratio ◽  
Soil Slope ◽  
Conductivity Anisotropy ◽  
Guangzhou City ◽  
Maximum Water ◽  
Seepage Characteristics

Evaluation of slope stability under rainfall is an important topic of Geotechnical Engineering. In order to study the influence of anisotropy ratio (kr = kx/ky) and anisotropy direction (α) on the seepage and stability of a slope, the SEEP/W and SLOPE/W modules in Geo-studio were utilized to carry out the numerical analysis of a homogeneous slope in Luogang District, Guangzhou City, China, which is based on the theory of unsaturated seepage and stability. Two kinds of soils (clay and sand) were included. Results show that: For sandy soil slope, the increase of kr promotes the rainfall infiltration, and the decrease of α prevents the rainfall infiltration. The maximum water content of the surface (MWCS) reaches maximum with the increase of kr and α. The rising height of groundwater (RHG) is −3–4 m and the safety factor (SF) is 1.3–1.7. For clayey soil slope, variations of kr and α have little impact on the seepage characteristics and slope stability. The MWCS remains almost the same. The rainfall infiltration depth (RID) is 0.5–1 m and the SF is about 1.7. Therefore, for sandy soil slope, it is not only necessary to consider the influence of kr, but also the influence of α. For clayey soil slope, it can be treated as isotropic material to simplify calculation.

Field study of rainfall infiltration into a grassed unsaturated expansive soil slope

2007 ◽  
Vol 44 (4) ◽  
pp. 392-408 ◽  
Author(s):  
Tony LT Zhan ◽  
Charles WW Ng ◽  
Del G Fredlund
Keyword(s):  
Field Study ◽  
Water Content ◽  
Pore Water ◽  
Surface Runoff ◽  
Expansive Soil ◽  
Rainfall Infiltration ◽  
Slope Instability ◽  
Simulated Rainfall ◽  
Soil Slope ◽  
Unsaturated Expansive Soil

A full-scale field study was conducted to investigate the effects of rainfall infiltration on a natural grassed expansive soil slope in China. A 16 m wide × 28 m long area was selected for instrumentation. The instrumentation included jet-filled tensiometers, moisture probes, a tipping bucket rain gauge, and a vee-notch flow meter. One artificial rainfall event amounting to about 370 mm rain depth in total was applied to the slope. The monitored results suggested that there was about a 3 day delay in the response of surface runoff, pore-water pressure, and water content to the commencement of the simulated rainfall. The depth of influence of the rainfall, depending on the elevation along the slope, ranged from 2.8 to 3.5 m. Positive pore-water pressures were measured within the influence depth, and there existed significant subsurface downslope flow at the end of the simulated rainfall, particularly near the lower part of the slope. A comparison of infiltration rates between the grassed area and a bare area nearby indicated that the presence of grass significantly increased the infiltration rate and reduced surface runoff. The cracks and fissures developed in the unsaturated expansive soil played an important role in the hydrological process.Key words: expansive soil, slope instability, infiltration, vegetation cover, grass, soil suction, water content, unsaturated soil.

The Effect of Rainfall Infiltration Time to the Unsaturated Soil Slope Stability

2011 ◽  
Vol 71-78 ◽  
pp. 4864-4867
Author(s):  
Guang Hua Cai ◽  
Hai Jun Lu ◽  
Wei He ◽  
Long Guan ◽  
Wei Qi Xu
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Rainfall Infiltration ◽  
Soil Slope ◽  
Soil Permeability ◽  
Rainfall Condition ◽  
Pressure Changes

Rainfall infiltration is currently one of the important factors in studying the soil-slope stability. By using saturated-unsaturated seepage theory, the traditional limit equilibrium method and so on, analyze the water content and the pore-water pressure changes under the rainfall condition, then analyze the influence mechanism of the slope stability. Through the Seep/W and the Slope/W of the GEO-Slope software, do the numerical simulation of the slope stability under the rainfall condition, to seek the distribution of pore-water pressure on the rainfall situation and the influence of the seepage field from various parameters such as rainfall intensity and the soil permeability coefficient, thus to study the slope stability.

scholarly journals Strength Characteristics and Slope Stability of Expansive Soil from Pingdingshan, China

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ju-yun Zhai ◽  
Xiang-yong Cai
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Expansive Soil ◽  
Friction Angle ◽  
Natural Soil ◽  
Soil Slope ◽  
The Finite Element Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
The Stability

By analyzing the characteristics of expansive soil from Pingdingshan, China, the shear strength parameters at different water contents, dry densities, and dry-wet cycles of expansive soil are obtained. It is found that, at higher soil-water content, the internal friction angle is 0° and the shallow layer of expansive soil slope will collapse and destroy; this has nothing to do with the height of the slope and the size of the slope. The parameters of soil influenced by atmosphere are the ones which have gone through dry-wet cycles, and the parameters of soil without atmospheric influence are the same as those of natural soil. In the analysis of slope stability, the shear strength parameters of soil can be determined by using the finite element method, and the stability coefficient of the expansive soil slope can be calculated.

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