Treatment of Mud Inrush Disasters and Risk Control for Underground-excavated Metro Tunnel in Self-weighty Saturated Slump Loess Ground Fissure

Objective Saturated loess slump may lead to underground cavity. When the underground tunnel passes through the fortified fissures section of the self-weighty saturated slump loess site, the encountered underground cavity may likely bring about mud in-rush disaster. Effective treatment measures need be taken to control the construction risks. Method With the project of a shallow-buried underground-excavated tunnel passing through the ground fissure in a place of China as example, the overview and geological situation of the project is introduced and the mud inrush disaster is summarized. Geological exploration finds that there is a loess cavity in the ground fissure fracture zone above the right metro line of the tunnel. According to the stratum characteristics of the cavity and the mud inrush risk features, construction measures such as spraying concrete on hanged net, small pipe grouting consolidation, steel and support reinforcement, and grouting back-filling of the cavity are taken. Based on this, the risk control measures for the cleaning of tunnel mud inrush and the secondary excavation process of the tunnel are further elaborated. Result & Conclusion The treatment measures for the mud inrush disaster in the above project and the risk control measures for the cleaning of mud inrush and the tunnel secondary excavation process are feasible and safe. With the measures being taken, the danger is shortly under control, ensuring the safety of the surrounding buildings.