南京纬三路过江通道泥水盾构带压开舱开挖面最小支护压力确定

南京纬三路过江通道采用两台直径14．93m的泥水盾构施工。盾构机在长距离穿越粗砂、卵砾石等复合地层时，刀盘刀具会产生较大磨损，因而需要进行停机带压检修。带压作业时，部分隧道开挖面仅由气压进行支护。针对气压支护开挖面在带压开舱时开挖面最小支护压力的设定问题，通过建立有限元三维开挖面稳定分析模型，研究了极限状态下盾构开挖面保持稳定的最小支护压力，并与工程计算和相关模型试验结果进行比较，确定了具有一定安全系数的开舱支护压力。

Calculation of the minimum excavation face support pressure for opening chamber in slurry shield in Nanjing Weisan Road River Tunnel

Nanjing Weisan Road River Tunnel was constructed by two slurry shield TBMs of which the diameters are 14.93 m. As passing through coarse and gravel sand with a long distance, the cutter head and cutters were worn seriously that need to be examined and repaired by hyperbaric intervention. The excavation face was supported by compressed air during hyperbaric intervention. In order to determine the minimum support pressure of the tunnel face, a three dimensional finite element model for analyzing the stability of excavation face is established. The minimum supporting pressure under the limit state is calculated by this model. By comparing with experimental results, the minimum support pressure to excavation face with a safety coefficient for hyperbaric intervention is confirmed.