Study of SPH simulation on tunnel face collapse

Maintenance measures for tunnel portal zones have attracted increasing interest owing to the increased collapse risk of slopes by severe torrential rain and inland earthquakes in Japan in recent years. However, these large-scale collapse behaviours cannot be simulated by finite difference method (FDM) analysis. In this study, we applied the smoothed particle hydrodynamics (SPH) method to analyse the collapse behaviour of the tunnel face under construction and the effect of the stabilization method. First, we simulated the collapse behaviour at the tunnel portal zone by two-dimensional SPH simulation and compared
it with an aluminium-bar experiment, and we showed that the SPH method is effective to model the overall tendency of the large deformation and the collapse behaviour in the experiments. Second, we simulated the collapse behaviour using the SPH method in the real tunnel portal zone collapse and provided a restraint result for collapse using facebolts. Therefore, we demonstrated that the SPH method is an effective technique to evaluate reinforcement measures.