Numerical modelling of hydro‐mechanical behaviour of collapsible soils

Abstract

SUMMARYThis 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.

Using modified state surface approach to select parameter values in the Barcelona basic model

“…Sheng et al [11] considered all existing elastoplastic models variants of the BBM. In addition, the BBM is one of the few elastoplastic constitutive models for unsaturated soils that have been implemented within finite element codes and applied to the analysis of real boundary value problems including high-level nuclear waste disposal (e.g., [15]), earthworks (e.g., [16]), and field tests (e.g., [17]). However, at present, there is no well-established, simple, and objective method for selecting parameter values in the BBM, and this has been one of the major obstacles to the dissemination of this constitutive model beyond the research context [18].…”

A New Procedure for Determining Parameter Values in the Barcelona Basic Model

“…Among these, the Barcelona Basic Model (BBM) proposed by Alonso et al (1990) has had a pioneering role and is one of the few elasto-plastic constitutive models for unsaturated soils which have seen relatively widespread implementation into finite element codes and application to real boundary value problems (Alonso et al 2005, Costa et al 2008and Gens et al 2009. However, there are no well-established methods for selecting parameter values in the BBM, which has hindered dissemination of the model beyond the research context.…”

Unsaturated Soils: Research and Applications

“…Among these, the Barcelona Basic Model (BBM) proposed by has had a pioneering role and is one of Francesca D'Onza Università di Napoli Federico II, Napoli, Italy e-mail: fdonza@unina.it Domenico Gallipoli ⋅ Simon J. Wheeler University of Glasgow, Glasgow, UK e-mail: domenico.gallipoli@glasgow.ac.uk, simon.wheeler@glasgow.ac.uk the few elasto-plastic constitutive models for unsaturated soils which have seen relatively widespread implementation into finite element codes and application to real boundary value problems (Alonso et al 2005, Costa et al 2008and Gens et al 2009. However, there are no well-established methods for selecting parameter values in the BBM, which has hindered dissemination of the model beyond the research context.…”