The control technology of the large deformation in weak surrounding rock with extreme crustal stress for Muzhailing Tunnel.

Based on the dynamic design of the large deformation of weak surrounding rock in Muzhailing Tunnel, the article introduced the special geological environment of the tunnel, analyzed the causes of the primary support intruding into tunnel structure gauge and the secondary lining cracking during construction, and studied the special measures to solve the problem of the large deformation in weak surrounding rock with extreme crystal stress, such as the multiple support system, enlargement of the advance heading for stress release, the reinforcement of long system anchor bolt (anchor cable), the reinforcement of invert steel truss and the setting of cushion structure. The engineering practice suggested, the technical countermeasures adopted were safe, reliable and effective, and the problems to be solved in construction were discussed, which could be used for reference in similar projects. [ABSTRACT FROM AUTHOR]