Abstract:

Rock mass is a combination of blocks and interfaces. Discontinuity of displacement field is caused by local shear deformation along interfaces, which has great influence on mechanical performances of rock mass. Discontinuity on slip plane is depicted with an assemblage of continuous functions, and mathematical model which is capable to consider local shear deformation along interfaces is obtained. Analytical solutions of surrounding rock bearing capacity of circle tunnel are deduced using the model when the stress-slip curve of rock has a strengthening phase. The influence of slip planes in rock on bearing capacity of surrounding rock is studied. It is concluded from analysis that the self-bearing capacity plays a great role in stabilization of deep tunnel surrounding rock, which is remarkably affected by strengthening phase of stress-slip curve. There are direct relations between surrounding rock pressure and depth or dimension of tunnel as well as physical or mechanical characteristics. The formation of unstable dynamical response is controlled by rock mass parameter m, which has relation with softening degree on interface, energy translation, geometry size of dissipation structure and elastic modulus.

Key words: bearing capacity, discontinuous displacement field, surrounding rock pressure, slip plane