Water inrush, which is a major cause of geological disasters during tunnel excavation, can worsen construction conditions and result in casualties. It is thus important to study the water inrush process for mitigating and preventing water inrush disasters in tunnel construction. The tunnel water inrush problem involves solid–fluid interactions. The coupling of the parallel three-dimensional discontinuous deformation analysis (3-D DDA) and 3-D smoothed particle hydrodynamics (3-D SPH) is suitable for analyzing this problem. The critical condition of a block under water pressure was first investigated to check the validity of the 3-D coupled DDA-SPH method. Further, a tunnel water inrush phenomenon was reproduced, and the mechanical behaviors of tunnels were explained with respect to the thickness T of the rock wall, the initial water height H, and the presence and location of a water outlet. The simulation results show that the tunnel deformation increases as T decreases and as H increases. The tunnel deformation was found to be larger when there was a water outlet; however, the location of the outlet had a slight effect on the deformation.

突水是隧道开挖过程中发生地质灾害的主要原因，会恶化施工条件，造成人员伤亡。因此，研究突水过程对于减轻和预防隧道施工突水灾害具有重要意义。隧道突水问题涉及固液相互作用。平行三维不连续变形分析（3-D DDA）和3-D平滑粒子流体动力学（3-D SPH）的耦合适用于分析这个问题。首先研究了水压下块体的临界条件，以检查 3-D 耦合 DDA-SPH 方法的有效性。此外，还再现了隧道突水现象，并根据厚度T解释了隧道的力学行为岩壁的初始高度H以及出水口的存在和位置。模拟结果表明，隧道变形随着T的减小和H的增加而增加。有出水口时隧道变形较大；然而，出口的位置对变形有轻微的影响。