Liangjiayuanzi Tunnel Project for the 19th Contract Section of Jihuai Expressway in Hunan Province

Jihuai Expressway is the fifth vertical in the "Five Vertical and Seven Horizontal" highway planning in Hunan Province, and is an important section of the National Baomao Expressway. The Liangjiayuanzi Tunnel in this bid section is designed as a two-hole three-center circular curved side wall structure tunnel with a separate upper and lower line, with the left line being 930m long and the right line being 920m long. Most of the tunnels are weak surrounding rocks with rheological deformation characteristics and extremely poor stability. After the tunnel is excavated, the surrounding rock slowly moves to the excavation space and converges, which is manifested as the side wall of the tunnel gradually moves inward, the bottom plate is slowly raised, and the vault is squeezed and cracked, which seriously affects the normal construction of the tunnel. Quality and safety. In response to the above problems, the project construction personnel took measures to reduce the disturbance of the surrounding rock by the excavation construction, rationally arranged the construction, and the inverted arch closely followed the tunnel face and quickly closed into a ring, which effectively solved the technical problems of tunnel construction.