Study on Construction Optimization Method of Tunnel Crossing Fault Fracture Zone

Abstract

When a highway tunnel intersects a fault fracture zone, the excavation process disrupts the surrounding weak and fragmented rock mass, compromising the stability of the fault zone. This study compares the deformation and stress distribution of the surrounding rock using the reserved core soil method, central diaphragm (CD) method, and cross diaphragm (CRD) method during tunnel excavation through fault fracture zones. Among these, the CRD method is identified as the safest construction technique. Additionally, to address the significant deformation of the surrounding rock when tunneling through fault zones, the impact of various pre-support and advance reinforcement techniques on rock mass deformation is analyzed. By comparing the full-ring grouting method with the optimized reinforcement zone approach, the findings demonstrate that optimized grouting significantly reduces disturbance to the fault fracture zone during excavation, thereby enhancing the overall stability of the surrounding rock mass.