Reinforcement Mechanism and Mechanical Analysis for Pipe Roof Support Used in Subway Station With Shallow Tunnel Construction Method

According to engineering practice in Beijing metro line 10 Huangzhuang subway station 126m advance pipe roof was used,the reinforcement mechanism for pipe roof is studied.Advantages and disadvantages for the existing pipe roof calculation models are compared and improved pipe roof calculation model is put forward.With this model the dynamic process for pipe roof deformation and the impact factors for pipe roof in ground settlement control are studied.Monitoring data indicated that without pipe roof ground surface settlement in line 4 Huangzhuang subway station induced by pilots drift in is 80mm while ground surface settlement is reduce to 30mm with pipe roof in the pilots drift in line 10 Huangzhuang subway station,which proved that pipe roof is very useful in ground surface settlement.