Abstract:

Deformation and cracks occur to the lining of Xiyang tunnel. Analysis is made on the defect situation and the causes for the defects, and alternative solutions, i.e., arch replacing solution and cutandcover solution, are proposed. Numerical simulation analysis is made in terms of the plasticized zones, the internal forces of the primary support and the safety coefficient, which concludes that the arch replacing solution plus grouting to consolidate the surrounding rocks is the most effective solution. At last, countermeasures to cope with the cracks are proposed. After the solution is adopted, the ground surface settlement, crown settlement and convergence tend to be stable.

Key words: Xiyang tunnel, defect, numerical simulation, arch replacing, cut and cover method