Numerical modelling of laboratory soil desiccation cracking using UDEC with a mix-mode cohesive fracture model

• A mixed-mode cohesive fracture model for laboratory soil desiccation simulation
• Correlate the micro-parameter to macro-parameter
• Investigate the desiccation cracking influential factors
• The cohesive fracture model has potential application to field soil desiccation.

This paper presents the application of the hybrid continuum-discrete element method, i.e. Universal Distinct Element Code (UDEC), to simulate soil desiccation shrinkage and cracking. Herein, soil is modelled using a mix-mode cohesive fracture model that combines tension, compression and shear material behaviour. The fracture model considers both elastic and inelastic (decomposed to fracture and plastic) displacement, with the norm of the effective inelastic displacement being used to control the fracture behaviour. The applicability and capability of the proposed approach is demonstrated through numerical simulations of laboratory linearly-constrained desiccation test. Good agreements with the laboratory observations have been obtained. The dominant influencing factors on soil desiccation cracking have been assessed, several factors including shear strength and tensile strength of soil-base, and soil sample thickness were identified to have a significant controlling influence on desiccation cracking.