Study on Roof-Jacking Construction Technology for Inclined Shaft Into Main Tunnel of Long High-Speed Railway
Compared with conventional tunnel excavation,the intersection of an inclined shaft and the main tunnel is character-ized by a gradually varying excavation cross-section,large spans,and complex structural configurations.In addition,the initial support undergoes multiple stress redistributions during construction,resulting in high difficulty and significant safety risks such as roof collapse and block failures.Focusing on the inclined shaft construction in the Fankuai Tunnel along the Xi'an-Chongqing High-Speed Railway,this study adopts roof-jacking construction methods.These include small-diameter pipe grou-ting and the reinforcement of irregular steel arches in the transition section,followed by pilot tunnel excavation in both longitu-dinal and transverse directions,and ultimately a three-step longitudinal excavation of the main tunnel.Monitoring data indicate that the vault deformation and the horizontal convergence of surrounding rock remain within acceptable limits.This roof-jacking approach effectively controls deformation in the intersection zone,yielding favorable overall performance and a scientifically sound construction scheme.
万方数据
维普
