Numerical modelling of desiccation cracking of clayey soil

Thi Dong Vo,Anh Minh Tang,Sahar Hemmati,Ahmad Pouya,P Delage,A.-M Tang,S Ghabezloo,J.-M Pereira,Y.-J Cui

doi:10.1051/e3sconf/20160908009

Thi Dong Vo, Anh Minh Tang + Show 7 more

Open Access

https://doi.org/10.1051/e3sconf/20160908009

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Abstract

The formation and propagation of desiccation cracks in soil is an extremely complex phenomenon because of the coupling between hydraulic and mechanical behaviour of soil, which are constituted here by the presence of capillary forces and discontinuities. The formation of a cracks network strongly influences the mechanical and hydraulic properties of soil. The main objective of this research is to study the evolution of suction and strain fields, the initiation and propagation of cracks under the effect of drying, using the finite element method. A simulation of a soil sample with four cohesive joints shows the results similar to experimental data. In addition, a simulation of multijoints shows that cracks does not open in all potentials positions and it gives similar spacing.

Highlights

The desiccation cracking is a common phenomenon in soils and rocks
This work presents an approach for desiccation cracking simulation talking into account the hydro-mechanical coupling: flow and deformation in presence of cracks by using the finite element (FEM) code Porofis
The simulation including the cohesive joints shows that this approach allows simulating two phases of desiccation process: the consolidation one without cracking and the cracks development one

Summary

Introduction

The desiccation cracking is a common phenomenon in soils and rocks. The essential mechanisms of initiation and propagation of desiccation cracking are not yet well understood, and the method to predict, control or avoid cracking is inadequately developed. Especially in clayey soils, the water content decreases due to evaporation This reduction of water content is accompanied with increase of suction and effective stress which causes shrinkage. If the shrinkage is restrained (by frictional boundary conditions, concentration of stress or gradient of humidity...), it will generate a tensile stress. When this tensile stress reaches the tensile strength of the material, a crack network can be formed. The desiccation cracks increase infiltration of fluid and influence the transport of pollutions [1][2] They affect the performance of coverage of waste disposal and decrease the strength of earth embankments [3][4]

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