Modelling of Coupled Process of Rainfall Infiltration and Internal Erosion Within Unsaturated Deposited Soil Slopes

被引：0
|
作者：
Lei X. [1 ,2 ,3 ]
Liu E. [1 ]
He S. [2 ]
Wu L. [3 ]
Yang Z. [2 ]
机构：
[1] School of Water Resource & Hydropower, Sichuan Univ., Chengdu
[2] Inst. of Mountain Hazards and Environment, CAS, Chengdu
[3] State Key Lab. of Geohazard Prevention and Geoenvironment Protection, Chengdu Univ. of Technol., Chengdu
来源：
Gongcheng Kexue Yu Jishu/Advanced Engineering Sciences | 2021年 / 53卷 / 02期
关键词：
Deposited soil; Fines migration; Internal erosion; Modeling; Rainfall infiltration; Slope stability;
D O I：
10.15961/j.jsuese.202000001
中图分类号：
学科分类号：
摘要：
The loose deposited soils in the mountainous area of western China are usually widely graded and weakly consolidated. Upon rainfall infiltration, the fine particles within these soils are prone to migrate in the pores formed by those coarse particles, which changes the soils' hydro-mechanical characteristics and destabilizes the slope. In order to study quantitatively the intrinsic evolution law of this rainfall-induced seepage-erosion coupled process within deposited soils and its influence on the slope stability, the fine particle migration phenomena observed within unsaturated deposited soil slopes in both the slope and pore scales were analyzed. Based on the mixture theory, a seepage-erosion coupled model capable of capturing the fine particle migration process within unsaturated soils was proposed. This model was then implemented into a finite element code, and was used to simulate the rainfall-induced seepage-erosion coupled process within a one-dimensional unsaturated soil column. Combined with the infinite slope model, the influences of erosion-induced soil permeability, water retention capacity and strength changes on the rainfall infiltration process as well as on the slope stability were analyzed quantitatively. Through numerical simulation, the intrinsic shallow slope failure mechanism, trigged by the formation of a relatively impermeable layer due to the fine particle migration-induced local change of soil permeability, was explained. It was pointed out that both the water retention capacity and shear strength of the deposited soils will be weakened due to the loss of fine particles, which will accelerate the rainfall-induced seepage-erosion process within the slope, and hence accelerate its failure process. In view of the fact that the changes of soil permeability, water retention capacity and strength due to the seepage-erosion coupled process are all adverse to the slope stability, it is therefore suggested that special attention should be paid to the fine particle migration effect when evaluating the stability of deposited soil slopes under rainfall infiltration. Copyright ©2021 Advanced Engineering Sciences. All rights reserved.
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页码：28 / 37
页数：9
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