Study on dynamic rainfall infiltration characteristics of soil slopes based on a dual-permeability model

doi:10.16265/j.cnki.issn1003-3033.2025.S2.0018

Abstract

Abstract:

To enhance landslide prediction and early warning capabilities and to optimize engineering disaster prevention and mitigation design, a non-saturated seepage model incorporating the coupling effect between matrix and fractures was developed based on dual-permeability theory. The model systematically accounted for rainfall intensity, rainfall duration, fracture permeability, spatial distribution and connectivity of fractures, matrix permeability, and the initial water content of the soil, enabling a realistic representation of water competition, migration, and coupling between the matrix and fracture domains. By using the improved rainfall boundary condition and considering the characteristics of unsaturated soil flow, COMSOL Multiphysics finite element software was employed as the computational platform, and the interactions between water in the matrix and fracture domains were comprehensively analyzed to reveal the rainfall infiltration characteristics of homogeneous soil. The results show that the presence of fractures significantly accelerates the initial infiltration rate and, under specific conditions, forms preferential flow paths, inducing local saturation; meanwhile, matrix suction plays a dominant role in water redistribution, and the competition and coupling between the matrix and fracture domains have a decisive effect on the spatiotemporal distribution of rainfall infiltration and the evolution of pore pressure.

Key words: dual-permeability medium, rainfall infiltration, unsaturated seepage, matrix domain, fracture domain

CLC Number:

X936

SUN Changkun, WU Haifei, ZHANG Yihai, YANG Jianglin, YUAN Yu, YUAN Yunxing. Study on dynamic rainfall infiltration characteristics of soil slopes based on a dual-permeability model[J]. China Safety Science Journal, 2025, 35(S2): 50-57.

Figures/Tables 11

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名称	数值
裂隙饱和渗透系数K_sf/(m·s^-1)	5.26×10^-6
基质饱和渗透系数K_sm/(m·s^-1)	5.26×10^-7
裂隙体积分数w_f	0.15
基质体积分数w_m	0.85
水量转换系数α_w/m^-2	0.2
耦合长度尺度L/m	10^-3