TY - JOUR
T1 - Hybrid discrete-continuum approach to model hydromechanical behavior of soil during desiccation
AU - Tran, Khoa M.
AU - Bui, Ha
AU - Nguyen, Giang D.
N1 - Funding Information:
Funding support from the Australian Research Council via projects DP160100775 (Ha H. Bui), DP170103793 and DP190102779 (Ha H. Bui and Giang D. Nguyen), and FT200100884 (Ha H. Bui) is gratefully acknowledged. This research was undertaken with the assistance of resources and services from the National Computational Infrastructure (NCI), which is supported by the Australian Government.
Publisher Copyright:
© 2021 American Society of Civil Engineers.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/10
Y1 - 2021/10
N2 - 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.
AB - 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.
KW - Crack pattern
KW - Desiccation cracking
KW - Discrete element method (DEM)
KW - Hydromechanical behavior
KW - Shrinkage
UR - http://www.scopus.com/inward/record.url?scp=85112079751&partnerID=8YFLogxK
U2 - 10.1061/(ASCE)GT.1943-5606.0002633
DO - 10.1061/(ASCE)GT.1943-5606.0002633
M3 - Article
AN - SCOPUS:85112079751
SN - 1090-0241
VL - 147
JO - Journal of Geotechnical and Geoenvironmental Engineering
JF - Journal of Geotechnical and Geoenvironmental Engineering
IS - 10
M1 - 04021102
ER -