A modified SPH framework of for simulating progressive rock damage and water inrush disasters in tunnel constructions

Abstract

To date, numerically simulating the Fluid–Solid Interaction (FSI) and the entire process of host rock damage and water inrush involved in tunnel construction relies intensively on hybrid methods of two or more numerical codes, which commonly encounter deficiency in learning, modelling and computation. A modified framework of Smoothed Particle Hydrodynamics (SPH), the Coupled Discontinuous SPH (CDSPH) method, was developed to simulate cracking, contacting and large deformation of rock blocks, free surface flow and the FSI for water/mud inrush disasters in tunnel construction through water–rich stratums. The failed SPH particles were transformed to discontinuous particles and new contacts between these particles were formed to simulate the frictional slip and separation/compression between fracture walls. The improved SPH method was employed to a water inrush case of a tunnel and the simulation results indicate that the entire process of progressive rock damage, water inrush and flooding are precisely reproduced by the improved method. The greater kinematic viscosity of fluids and rock wall thickness can increase the flow velocity and hence increasing the impact pressure of floods, and the failure pattern of the rock wall changes from partial outburst to complete failure. Vulnerability analysis of the water inrush reveals a complete damage status for people, vehicles and Non-RC frame buildings, and a moderate to complete damage to RC frame buildings at the tunnel portal. This single code is capable of simulating the behaviour of rocks, fluids and their interactions in catastrophic disasters that is potentially applicable to a wide spectrum of surface and subsurface problems involving FSI.