Research on Pre-grouting Strengthening Technology of Shallow and Large Section Metro Tunnel through Fault Fracture Zone

Through the pre-grouting engineering practice of F1 fault fracture zone in People's Hall Station of Qingdao Metro Line 4, the research on the pre-grouting Strengthening Technology of shallow and large section metro tunnel through fault fracture zone is carried out, and the effective means to control the crossing fault fracture zone of the shallow and large section metro tunnel are explored. The results show that it is an effective method to treat the collapse of fault fracture zone by using the combined grouting method of first detection and grouting, and the combination of surface grouting and tunnel grouting in the shallow and large section metro tunnel. For the fault fracture zone near the sea, in order to prevent the continuous erosion of seawater ions to fault fracture zone and station structure, the cement-water glass and sulpho-aluminate cement materials can be considered on both sides of the station, and ordinary portland cement and sulpho-aluminate cement can be used in the middle of the station to ensure the safety and stability of the station, which also could reduce the cost of construction as much as possible.