Research on Stability Mechanism of Fissured Loess Slope Influenced by Rainfall and Evaporation

2012 ◽  
Vol 170-173 ◽  
pp. 380-385
Author(s):  
Ai Bing Jin ◽  
Fu Gen Deng ◽  
Long Fu Li ◽  
Min Zhe Zhang

Based on saturated-unsaturated seepage mechanism, the features of pore-water pressure, strain and displacement of fissured and fissureless slope are analyzed by using the finite element method. At the same time, pore-water pressure, displacement and safety factor of fissured and fissureless slope as well as fissured slope with different depth and width are comparatively analyzed under the condition of rainfall and evaporation. The research results show that, under rainfall condition, the existence of fissures could change the boundary of soil infiltration and seepage filed distribution, lead to stress concentration and make plastic strain around the fissures area. In addition, as the rainfall response time increasing, the plastic zone around the fissures will spread to the surrounding, thus, the new micro-fissures would be produced during the process of the fissures expansion. Evaporation will reduce the shallow soil water content, increase suction and slope stability. Under the condition of rainfall and evaporation, slope stability is affected more seriously by the fissure depth, but less by the width.

2012 ◽  
Vol 204-208 ◽  
pp. 487-491
Author(s):  
Jian Hua Liu ◽  
Zhi Min Chen ◽  
Wei He

Based on the saturated-unsaturated seepage theory and considering soil-hydraulic permeability coefficient characteristic curves of rock slope, the variation of suction in unsaturated region and transient saturated zone formation of rock slope were analyzed. Combined with engineering example, the strength reduction methods were adopted to analyzing the rock slope stability influence factors considering unsaturated seepage with different rainfall intensity and duration. The results show that the flow domain owing to rainfall infiltration mainly appears surface layer region of slope. The rainfall infiltration caused the groundwater level rise, the rising of transient pore water pressure and the fall of suction in unsaturated region caused the slope stability decrease. The rainfall intensity and duration have obvious influence on slope stability, and in the same rainfall duration condition, the safety coefficient of slope decreases with the accretion of rainfall intensity. With the rainfall duration increasing, the water in soil has more deep infiltration, the water content and pore water pressure was higher in the same high position, the decreasing of suction caused the safety coefficient of slope has more reduce.


2011 ◽  
Vol 71-78 ◽  
pp. 4864-4867
Author(s):  
Guang Hua Cai ◽  
Hai Jun Lu ◽  
Wei He ◽  
Long Guan ◽  
Wei Qi Xu

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.


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.


2011 ◽  
Vol 255-260 ◽  
pp. 3488-3492
Author(s):  
Bao Lin Xiong ◽  
Jing Song Tang ◽  
Chun Jiao Lu

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.


1993 ◽  
Vol 30 (3) ◽  
pp. 491-505 ◽  
Author(s):  
Delwyn G. Fredlund ◽  
Zai Ming Zhang ◽  
Karen Macdonald

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.


2020 ◽  
Vol 15 (1) ◽  
pp. 19-26
Author(s):  
Euthalia Hanggari Sittadewi

The ability of plants to carry out the functions of interception, evapotranspiration and root reinforcement provides an effective and contributes to an increase in slope stability. Canopy has a role in the process of interception related to the reduction of amount the infiltrated water and the rapid fulfilment of soil moisture. Through the evapotranspiration mechanism, plants can reduce pore water pressure in the soil so that the trigger force for landslides can be reduced and the soil will be more stable. The roots mechanically strengthen the soil, through the transfer of shear stresses in the soil into tensile resistance in the roots. Roots also bind soil particles and increase surface roughness, thereby reducing the process of soil displacement or erosion. There is a positive relationship between the density of the tree canopy with the value of rainfall interception, evapotranspiration with a decrease in pore water pressure in the soil and the ability of root anchoring and binding with an increase in soil shear strength, indicating that the function of interception, evapotranspiration and strengthening of plant roots have a positive effect on increasing slope stability. Plants selection that considers the level of interception, the rate of evapotranspiration and root reinforcement by adjusting environmental and slopes conditions will determine the success of slope stabilization efforts by vegetative methods.Keywords : interception, evapotranspiration, root reinforcement, slope stabilization.


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