Seismic Damage Characteristics and Repair Technology of Railway Tunnels Crossing Active Fault Zone

Based on the seismic damage rehabilitation project of Daliang tunnel in Lanzhou-Xinjiang high-speed railway crossing seismogenic faults, through field investigation, mapping, exploration and other methods, the deformation and damage characteristics of the railway tunnel crossing the active fault zone under near-field strong-earthquake effect were revealed. Combined with the seismic safety assessment conclusions, the multi-dimensional repair methods of earthquake-damaged tunnel in active fracture zone was proposed, which included protection and reinforcement, structural demolition and reconstruction, reserving deformation space, applying devices for the energy dissipation and shock absorption, structure segment design, and using ballastless track with large adjustment. These repair methods possess the rapid and safe characteristic during the construction, which could solve the related problems caused by the further deformation of active fracture in the subsequent operation stage, so as to achieve the adaptive effect of post-earthquake residual slip and moisture slip deformation structure and rapid repair of stick-slip dislocation damage. According to the feedback of field construction and monitoring results, the relevant repair plans were highly feasible, and the repaired tunnel structure has a good carry capacity. This study can provide practical experiences and useful references for the earthquake disaster recovery and seismic fortification of subsequent similar tunnel engineering.