Study on the Convergence of Surrounding Rock in Shallow Buried Unsymmetrical Pressure Tunnel Construction

In order to study the evolution law of tunnel convergence deformation during the construction of shallow buried unsymmetrical pressure tunnel, the deformation characteristics and evolution law of shallow buried unsymmetrical pressure tunnel during the three-step construction method are studied based on the background of Qingshui No. 2 tunnel project and numerical simulation. The results show that: with the tunneling, when the tunneling depth is less than 40m, the settlement deformation gradually decreases, and the maximum settlement is at the entrance; When the tunnel footage is greater than 40m, the settlement deformation first increases and then decreases. The maximum settlement of the arch crown is 15m in front of the tunnel face, while the maximum settlement of the arch shoulder is 20m in front of the tunnel face; The maximum value of arch waist convergence appears at 10m in front of the tunnel; The effective combination of numerical simulation and monitoring technology can provide guidance for engineering practice.