Analysis of Water and Mud Inrush in Tunnel Fault Fracture Zone—A Case Study of Yonglian Tunnel

Water and mud inrush disaster is easily induced during tunnel construction through water-rich fault fracture zones. In this paper, based on the field data, process of water in tunnels introduced detail, generation conditions evolution mechanisms have been analyzed. Results show that key factors include poor strata lithology, abundant groundwater excavation disturbance. These provide material conditions, source power start-up for inrush, respectively. The can be divided into three stages: generation, development occurrence. During stage, a seepage channel expands continuously, with flow increasing gradually until large range loose zone formed. amount softened muddy rock mass accumulates around tunnel. occurrence “protective layer” initial supports suddenly lose stability are destroyed. research results could some references effective prediction forewarning similar engineering disasters.