Influence of reinforcement range on ground settlement of shallow-buried super-large-diameter shield tunneling in soft soils

The shield method is the main construction method for the excavation of underground tunnels in soft soil areas, but the impact of shallow-buried super-large-diameter shield tunneling in soft soils on ground settlement needs to be further studied. Based on the case of Weizhou Tunnel in Hengqin of Zhuhai the influence of the reinforcement range on the surface settlement of shallow-buried super-large diameter shield tunneling in soft soils is studied by using the finite element software. The results show that when t=0.00D, the maximum surface settlement is about 50 mm, when t=0.20D, the maximum surface settlement is about 8 mm, which is about 84% less than the maximum settlement at t=0.00D%, and the soft soil layer can effectively reduce the impact of tunnel excavation on surface settlement after reinforcement. Meanwhile, the law of lateral surface settlement changes during the different construction stages of shield tunnels is analyzed, and the shield tunneling machine disturbs the ground surface during the monitoring of the cross section. The degree is the largest, and the cumulative subsidence accounts for about 50% to 60%.