Numerical Analysis of the Effects of Crack Characteristics on the Stress and Deformation of Unsaturated Soil Slopes

Abstract

Cracks induced by evaporation or rainfall have a great influence on the stability of unsaturated soil slopes, which can lead to landslides during the rainfall process. In order to study the effect of crack characteristics on the evolution of stress and deformation of unsaturated soil slopes, a series of numerical analyses under different conditions were performed using a coupled elastoplastic finite element program that we developed for unsaturated soil. When carrying out the numerical analyses, the effective stress for unsaturated soil proposed by Bishop and an elastoplastic double-hardening constitutive model for the soil skeleton were employed. The varying parameters, including the crack location, the discharge speed, evaporation rate, infiltration rate, and tensile strength, were investigated to study the coupling process of pore water pressure and deformation in the process of evaporation and rainfall infiltration. The numerical results showed that the minimum pore water pressure of the soil slope at the end of evaporation/rainfall decreased gradually and the crack width increased gradually as the crack set closer to the slope; the larger the discharge speed of pore air, the greater the crack width. With the increase in the evaporation rate, the pore water pressure of the soil slope reduced and the crack initiated earlier and became wider. As the infiltration rate increased, the pore water pressure of the soil slope and the crack width increased, but the decreasing duration became shorter. The change of tensile strength had little effect on the pore water pressure, but the development of the crack width changed with evaporation and rainfall infiltration.

Destabilization Mechanism and Stability Study of Collapsible Loess Canal Slopes in Cold and Arid Regions

“…Rahimi et al statistically evaluated the development law of the cracks and the influencing factors. The sliding damage of expansive soil canal slopes was mostly contributed to by various kinds of cracks [24,25]. Zhu et al studied the water infiltration characteristics of the canal under various cyclic conditions with centrifuge model tests and demonstrated that the shallow soil of the canal model was completely saturated in the wetting stage [26].…”

Experimental and Numerical Analysis of Soil Cracking Characteristics under Evaporation

“…e existence of cracks would cause important effect on soil properties. e cracks would not only reduce the soil strength [1], but also provide preferential pathways for fluid flow and increase water infiltration or contaminant solute transport into soils [2,3].…”

An advanced discrete fracture model for variably saturated flow in fractured porous media

“…Understanding variably saturated flow (VSF) in fractured porous media has great significance to many environmental and geotechnical applications, such as groundwater recharge in karst aquifers, (Mudarra and Andreo, 2011;de Rooij et al, 2013de Rooij, 2019, epikarst (Chang et al 2019) and unconfined chalk aquifers (Ireson et al, 2009), geological disposal of nuclear waste such as at Yucca Mountain in the United States where the unsaturated zone is estimated as potential site for disposal of high-level nuclear waste (Hayden et al, 2012;Ye et al, 2007), contaminant transport and infiltration of landfill leachate (Brouyère, 2006;Ben Abdelghani et al, 2015), infiltration through unsaturated saprock in hillslopes with shallow fractured shale bedrock (Guo et al, 2019), unsaturated flow and contaminant transport in saprolite (Van der Hoven et al, 2003;Alazard et al, 2016), water flow in cracked soils and stability of soil slopes with cracks (Pouya et al, 2013;Wang at al., 2019;Yang and Liu, 2020), seepage through fissured dams (Jiang et al, 2014), tunnel excavation (Gokdemir et al, 2019) and protection of structure foundations in contact with water (Zhao et al 2019).…”