Modélisation numérique des mouvements de sol induits par des excavations

Abstract

Numerical modeling of soil movements induced by deep excavations AbstractNumerical modeling of ground movements induced by excavations supported is a complex topic for which different parameters may have a significant influence on the final result, Firstly, this paper deals with the influence of the initial stress state with a numerical model of the installation steps of several diaphragm wall panels. Different calculations in two and three dimensions taking into or not these steps are carried out to highlight the effects of the initial stress state on deformation mechanisms induced by the excavation. Previously, a detailed study of ground motion generated during the execution of the walls is performed to identify changes in horizontal stress behind the retaining wall. Then, a study on the effects of nonlinearities in the elastic constitutive equations including a failure criterion M ohr-Coulomb type is performed. It identifies the links between elastic parameters of the constitutive laws and the calculated movements during an excavation.

State-of-the-art requirements verification process applied to numerical finite-element modelling of the deep excavation in soft soils

“…Examination of the results led him to identify four categories of structures, depending on the thickness of the soft seams, the safety factor of the settlement of the excavation bottom, and the rigidity of the support system. It is interesting to note that for the stations of the « Grand Paris Express », Daktera [46,47], Nejjar [48] and Burlon [49], give maximum horizontal displacements of the order of 15 to 20 mm for excavation depths close to 30 m, which gives a significantly lower u max /H ratio than the values found in previous references, of the order of 0.07% H. Several other works [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] in this area have…”