The Improved Theory of Synergetic Action Between Anchor Support System and Surrounding Rock-I·L·4S Mechanism Theory and Its Application in Tunnel Support Engineering

Tunnel surrounding rock support is a very complex composite structure, and its mechanical mechanism is very complex. In this paper, the interaction theory of bolt and surrounding rock, the theory of integral anchorage structure and the theory of tunnel anchorage coordination are analyzed. On this basis, the theory of tunnel anchorage coordination is improved and the improved synergetic action anchoring theory (I·L·4S) is proposed. The deformation and internal force results of the supporting bolt and lining in the model test completed by the author are analyzed, and the correctness of the proposed theory is verified. Through the analysis, the tunnel support system is a composite structure. On the one hand, the anchorage system provides radial binding force for the shallow surrounding rock, and transfers the additional load of the shallow surrounding rock to the deep surrounding rock to mobilize the bearing capacity of the surrounding rock; on the other hand, it forms a certain arch effect around the tunnel to assist the surrounding rock load. The essence of the interaction between the anchorage system and the composite surrounding rock structure, the parameter matching of the single support type of the bolt and the synergistic effect between the bolt and the lining are essentially deformation coordination and reasonable distribution of the surrounding rock load. The mechanism of bolt is insert lock stretch self-bearing support squeeze. The synergistic effect of anchoring composite structure has obvious effect on eliminating or reducing surrounding rock fracture, and the overall stability of tunnel has been greatly improved after the implementation of composite structure.