Modelling of a tunnel excavation in a non-cohesive soil improved with cement mix injections

The paper presents the results of a numerical analysis of the excavation of a tunnel in a non-cohesive soil. In situ test data recorded before and during the works are presented first. The constitutive law adopted and the procedure followed for modelling the injection phase is discussed next. It is shown that, in order to match the movements recorded within the soil mass, a rather complex procedure, allowing for either uniform diffusion of the mix or formation of mix lenses (‘claquage’), should be adopted. Calculated and observed data during the various phases of the excavation are then finally compared.