Abstract:

The safety of the reconstruction section of lining cracking in high geostress soft rock tunnel is important. Hence, the deformation and force characteristics of structure of the lining cracking section of Muzhailing Tunnel with high geostress soft rock are analyzed by field monitoring and numerical simulation. And then the safety of the structure is analyzed. The monitoring results show that most of the surrounding rock pressure and deformation is borne by the first three layers of support after reconstruction of lining cracking, and the lining stress is gradually reduced by layers of support, which can ensure the safety of the lining structure. The force and displacement states of tunnel before and after the reconstruction of lining cracking are analyzed by numerical calculation and comparison. The analytical results show that the growth trend of concrete stress and reinforcement stress in each position of lining after reconstruction are not obvious; it is calculated that the structural safety factors of the reconstruction section of lining cracking is in the range of 3.3-8.1, and the safety factors of each position is greater than those in the standard, which indicates that the structure is safe.

Key words: high geostress, soft rock tunnel, lining cracking, structural safety, field monitoring, numerical simulation