Hybrid Discrete-Continuum Approach to Model Hydromechanical Behavior of Soil during Desiccation
- 1 October 2021
- journal article
- research article
- Published by American Society of Civil Engineers (ASCE) in Journal of Geotechnical and Geoenvironmental Engineering
- Vol. 147 (10), 04021102
- https://doi.org/10.1061/(asce)gt.1943-5606.0002633
Abstract
Desiccation cracking in clayey soils occurs when they lose moisture, leading to an increase in their compressibility and hydraulic conductivity and hence a significant reduction of soil strength. The prediction of desiccation cracking in soils is challenging due to the lack of insights into the complex coupled hydromechanical process at the grain scale. In this paper, a new hybrid discrete-continuum numerical framework, capable of capturing hydromechanical behavior of soil at both grain-scale and macroscale, is proposed for predicting desiccation cracking in clayey soil. In this framework, a soil layer is represented by an assembly of discrete element method (DEM) particles, where each occupies an equivalent continuum space and carries physical properties governing unsaturated flow. These particles move freely in the computational space following the DEM, and their contact network and the continuum mixture theory are used to model the unsaturated flow. The dependence of particle-to-particle contact behavior on water content is represented by a cohesive-frictional contact model, whose material properties are governed by the water content. In parallel with the theoretical development is a series of experiments on three-dimensional (3D) soil desiccation cracking to determine essential properties and provide data for the validation of mechanical and physical behavior. Very good agreement in both physical behavior (e.g., evolution of water content) and mechanical behavior (e.g., occurrence and development of cracks, and distribution of compressive and tensile strains) demonstrates that the proposed framework is capable of capturing the hydromechanical behavior of soil during desiccation. The capability of the proposed framework facilitates numerical experiments for insights into the hydromechanical behavior of unsaturated soils that have not been possible before.Keywords
This publication has 48 references indexed in Scilit:
- Salient factors controlling desiccation cracking of clay in laboratory experimentsGéotechnique, 2013
- Determination of cohesive properties for mode I fracture from compacted clay beamsCanadian Geotechnical Journal, 2011
- Fundamentals of desiccation cracking of fine-grained soils: experimental characterisation and mechanisms identificationCanadian Geotechnical Journal, 2009
- Modelling of curling in desiccating clayCanadian Geotechnical Journal, 2004
- Microstructural deformation mechanisms of unsaturated granular soilsInternational Journal for Numerical and Analytical Methods in Geomechanics, 2002
- The Courant and Peclet Number criteria for the numerical solution of the Richards EquationWater Resources Research, 1993
- Cracking in drying soilsCanadian Geotechnical Journal, 1992
- A Closed-form Equation for Predicting the Hydraulic Conductivity of Unsaturated SoilsSoil Science Society of America Journal, 1980
- A discrete numerical model for granular assembliesGéotechnique, 1979
- A Comparison of Numerical Simulation Models For One‐Dimensional InfiltrationSoil Science Society of America Journal, 1977