Abstract:
Based on the experience of tunnels with high geostress conditions constructed in China, assessment cri? terion, geological characteristics of squeezed surrounding rock and suggestions for the rock mass classification are presented. A further analysis of geological factors of rock mass integrity, thickness, structure and geostress that affect initial support deformation is conducted, a classification method, which is based on relative deformation, the degree of cracking of the initial support, soft and hard rock, and an unsymmetrical load and section dimension, is discussed, and a design method for a tunnel in squeezed surrounding rock and systematic management techniques for large deformation are proposed.