Construction method for initial support during tunnel construction in fracture zone of high seismic zone

Abstract

The invention discloses a construction method for initial support during tunnel construction in a fracture zone of a high seismic zone. The construction method comprises the following steps: 1, detecting a rock stratum; 2, detecting underground water; 3, excavating a tunnel; 4, protecting the top; 5, integrally supporting. According to the construction method, gravel on the inner wall of the tunnel is closed and protected by a protective net first and then fixed by I steel and arched steel structures, and when a steel frame is fixed, surrounding rock on the inner wall of the tunnel can be completely closed, so that a phenomenon that the gravel does not fall from concrete in the step of spraying the concrete is avoided, tunnel construction is facilitated, and the safety of the tunnel construction is improved.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, and more specifically relates to a construction method for initial support in tunnel construction in a broken zone in a high earthquake zone. Background technique [0002] When the mine method is used for underground excavation construction, the surrounding rock support is generally divided into primary support and secondary lining, and the secondary lining is generally a concrete or reinforced concrete structure. Before the construction of the secondary lining, the support form immediately after excavation is called primary support. The initial support is after the excavation of the tunnel. In order to control the stress release and deformation of the surrounding rock, increase the safety of the structure and facilitate the construction, the structural layer with low rigidity and as a part of the permanent bearing structure is immediately constructed. Generally, there are shotcrete a...

AI Technical Summary

Problems solved by technology

[0003] However, there are some disadvantages in the use of the traditional primary support, such as: the traditional primary support generally only needs to be shotcrete after the excavation of the tunnel, or use anchor rods and steel frames to repair some loosened larger rocks. Carry out a simple support, but this method is only suitable for the situation where the nature of the surrounding rock is relatively stable. When performing initial support in the broken area of ​​some high seismic zones, because the area is in the seismic zone, the gravel in the surrounding rock of the tunnel More, if shotcrete is used for initial support, the gravel will fall easily before the shotcrete is solidified; if anchor rods and steel frames are used for support, at this time, due to too much gravel in the cofferdam, Comprehensive support cannot be carried out, so the existing primary support method is not suitable for the surrounding rock support of the tunnel in the fracture zone of the high seismic zone