Numerical modelling of hydro-mechanical behaviour of collapsible soils

This paper presents a numerical simulation of the response of unsaturated soil under different loads, with special attention devoted to the phenomenon of pore collapse during wetting. A coupled hydro-mechanical formulation, implemented in the computational code CODE_BRIGHT, is first presented. Then the model is applied to assess material parameter from laboratory tests and to simulate, as boundary value problems, new and appealing in situ tests designed in the Federal University of Pernambuco. The soil considered is a collapsible soil located in the semi-arid region of the northeast of Brazil. Two situations are analysed: (i) the soil is initially at its natural water content and then flooded at some determined stress level, (ii) the soil is previously flooded and then loaded. Comparison between output results of numerical simulations and experimental data shows a very good agreement, which validate to some extent the proposed experimental procedure and the model formulation. Copyright © 2007 John Wiley & Sons, Ltd.