Tunnelling-induced deformation on a masonry structure: a numerical approach

In this paper the analysis of a possible damage mechanism induced by shallow tunnelling to an ideal masonry structure is carried out using a numerical approach based on 2D FE analyses. The masonry structure is modelled adopting an advanced constitutive model which was specifically implemented in a commercial finite element code. The masonry structure, schematised as a block structure with periodic texture, is regarded at a macroscopic scale as a homogenized anisotropic media. The macroscopic model is shown to retain memory of the mechanical characteristics of the joints and of the shape of the blocks (de Felice et al., 2010). The overall mechanical properties display anisotropy and singularities in the yield surface, arising from the discrete nature of the block structure and the geometrical arrangement of the units. The soil, a medium consistency clayey material, is modelled by means of a simple linear elastic-perfectly plastic model. The numerical analyses were performed assuming, as a first simplified step, plane strain and plane stress con-ditions for the soil and the masonry structure, respectively. The investigation provides preliminary insights into the soil-tunnel-structure interaction by taking into account different values of volume loss, with reference to a typical wall-type masonry structure.