Centrifuge modelling of rainfall-induced slope failure in variably saturated soil

Abstract

This paper presents the results of centrifuge tests on rainfall-induced instabilities in variably saturated slopes. The roles of rainfall intensity and initial conditions, such as slope angle, porosity and degree of saturation of the soil, in the failure initiation and postfailure kinematics are considered. The failure patterns, infiltration profile and deformation at prefailure and postfailure stages are characterized. The results indicate that rainfall-induced slope failures usually follow one of the following two failure modes, i.e. slide-to-flow and flowslide failure modes. The former pattern is characterized by soil mass flow after initial failure along a continuous shear surface, while the latter is more relevant to the rapid increase in the saturation at the slope surface, resulting in surface erosion channels followed by the acceleration of the soil mass. The flowslide failure pattern usually gives rise to several superficial shear surfaces and longer run-out distances. The rainfall intensity and profiles of the degree of saturation play the key roles in initiating the slope failure at the prefailure stage and subsequently in mobilizing the soil mass at the postfailure stage. Our test data, together with the data from the literature, are presented in two threshold curves to define the critical condition of slope failure under rainfall infiltration.

Flowslide High Fluidity Induced by Shear Thinning

“…With increasing velocity, the granular mass gradually flowed in a more ordered manner as a viscous fluid as it entered the fluid phase, with a coordinated flow‐like velocity distribution, that is, the Bagnold profile. Such fluidized behavior is generally attributed to a shear‐induced positive pore pressure (Iverson et al., 2011; Okura et al., 2002; Take & Beddoe, 2014; Wang et al., 2021). However, no fluctuation of pore pressure was evident in this physical experiment (Figures 5m–5o).…”

A device for rainfall simulation in geotechnical centrifuges

“…Note that an attempt is not made to study the failure mechanism of the slope under rainfall conditions. This regard is explored in our companion paper [18]. Instead, we are focusing on the performance of the rainfall device.…”

Influence of Wind-Generated Wave Action on Mountain Reservoir Bank Collapse: A Case Study at the Lancang River, Western China

“…In recent years, experimental methods and numerical simulation methods have been applied to study the stability of slope under the rapid change of reservoir water level or rainfall. Based on centrifuge tests on rainfall-induced instabilities in variably saturated slopes, Wang et al indicated that rainfall-induced slope failures usually follow the slide-to-flow or flowslide failure modes [13]. Song et al have investigated the influence of rapid water drawdown on the seismic response characteristics of a reservoir rock slope by using numerical dynamic analyses and shaking table tests [14].…”