Theoretical and Numerical Studies of Rock-Support Interaction by Considering Imperfect Rock-Lining Interface

Rock-support interaction is the basis and premise of support structure design in tunnel engineering. In the conventional convergence-confinement method, the imperfect rock-lining interface is usually ignored. In this study, we present a mechanical model considering the imperfect interface and corresponding solution method for the analysis of rock-support system. Parametric study on the influence of interface on rock-support interaction indicates that: (1) rock-support system without considering imperfect interface is the limit cases in which rock-lining interface initial stiffness is very large or rock-lining interface maximum displacement is close to 0; (2) the smaller the interface initial stiffness and the larger the interface maximum displacement, the larger the displacement, plastic zone and load taken by rock mass, but the smaller the load shared by support structures; (3) no matter how the interface parameters change, rock mass is always the dominant load-bearer, while support structures share less load; (4) compared with surrounding rock and systematic bolt, the influence of interface on load taken by lining is more significant. This study can improve our understanding of rock-support interaction and determine the loads shared by surrounding rock and support structures, which contributes to the rational design and the safety of tunnel engineering.