Uncoupled evaluation of the structural damage induced by tunnelling

This paper illustrates an approximate procedure for the evaluation of the damage induced on existing buildings by the excavation of a tunnel. The method hinges on the development of a simplified structural model of the building, that can be readily incorporated into the finite-element mesh used to simulate the excavation of a tunnel. A first part of the article is devoted to the description of the equivalent structure and to the illustration of an identification procedure for the evaluation of its mechanical properties, based on appropriate scaling of the areal and inertial characteristics of the parent building. Then, the practical use of the method is illustrated by carrying out a series of three-dimensional numerical analyses of the excavation of an EPB tunnel, that include either the simplified or the fully detailed structural model of a masonry building. Using the results obtained with the complete building as a reference, it is shown that the simplified formulation is quite effective in capturing the main features of the soil-structure interaction for the problem at hand. Cases in which the method is less successful are discussed as well, indicating a suitable adjustment of the identification procedure for the simplified structural model.