Discrete-element modelling of underground tunnel response to reverse fault rupture in sand

The interaction between an underground tunnel in a sand deposit while a reverse fault rupture propagates from the bedrock to the ground surface was simulated using the discrete-element method (DEM). The propagation pattern of the fault ruptures and the deformation profiles of the soil at the ground surface were analysed in detail considering the effects of the location and rigidity of the tunnel. The DEM simulations were verified against a set of centrifuge laboratory experiments. The DEM simulations were also compared with a set of finite-element numerical models and the efficiency of each method for the simulation of fault rupture-tunnel interaction was assessed for the first time. Both the DEM and the continuum numerical models were found to be effective complementary tools, capable of providing valuable insight into fault-tunnel interaction mechanisms. However, the DEM simulations produced a better correlation with the experimental results.