Rock and Soil Mechanics ›› 2022, Vol. 43 ›› Issue (8): 2305-2316.doi: 10.16285/j.rsm.2021.6831

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Reliability analysis of slope under rainfall infiltration considering preferential flow model

YAO Yun-qi1, 2, ZENG Run-qiang1, 2, MA Jian-hua2, 3, MENG Xiang-pei1, 2, WANG Hong1, 2, ZHANG Zong-lin1, 2, MENG Xing-min1, 2   

  1. 1. School of Earth Sciences, Lanzhou University, Lanzhou, Gansu 730000, China 2. Technology & Innovation Center for Environmental Geology and Geohazards Prevention of Gansu Province, Lanzhou University, Lanzhou, Gansu 730000, China 3. College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, Gansu 730000, China
  • Online:2022-09-30 Published:2022-09-30
  • About author:Yao Yun-qi, male, born in 1997, Graduate student, mainly engaged in the study and research of slope stability evaluation and loess landslide.
  • Supported by:
    the National Key R&D Program of China (2018YFC1504704), the Youth Scholars of National Natural Science Foundation of China (41602348), the Construction Project of Gansu Technological Innovation Center(18JR2JA006) and the Fundamental Research Funds for the Central Universities (lzujbky-2021-sp01).

Abstract: Rainfall-induced landslides are the most common geological hazard in the world, and the effect of preferential flow infiltration has been neglected for a long time regarding the slope reliability analysis under rainfall infiltration. The preferential infiltration under rainfall conditions is solved numerically by Comsol Multiphysics, and the slope factor of safety is calculated using an infinite slope model. An improved Cholesky decomposition method is applied to generate spatially correlated random fields, and the slope reliability during rainfall is analyzed using the Monte Carlo method. Combining the deterministic and reliability results to compare the variation of slope factor of safety between the homogeneous infiltration and the preferential infiltration during rainfall, it can be found that: (1) the preferential infiltration model is safer when the rainfall intensity is low, while the homogeneous infiltration is more stable at higher rainfall intensity; (2) the spatial variability of infiltration parameters is the crucial factor of slope failure in homogeneous infiltration, while the slope instability of preferential infiltration is mainly caused by the rapid advance of the wetting front; (3) for the study of preferential infiltration model, the slope has a higher probability of failure when the hydraulic exchange intensity between the matrix domain and the preferential domain, while smaller hydraulic exchange intensity may affect the slope failure at the bottom.

Key words: infinite slope model, rainfall infiltration, dual permeability model, slope reliability, Monte Carlo simulation