Finite element prediction of the effects of faulting on a shallow tunnel

A numerical estimation is presented of the effects induced in an existing tunnel by the development of a fault from the deep bedrock. The spreading of the fault within the alluvial deposit hosting the tunnel, and the consequent effects on its permanent liner and at the surface of the soil deposit, are studied in static conditions through a series of elastic-plastic, plane strain finite element analyses. They account for the reduction of the shear strength and stiffness characteristics of the faulting zone with increasing irreversible strains