Research on Rheological Properties of Silty Mudstone and Deformation of Tunnel

Combining with engineering cases and the creep characteristic of silty mudstone obtained by rock creep test, this paper studied the rheological properties of high-stress silty mudstone and deformation of the deep buried tunnel. Rock creep tests illustrated that the mechanical properties of silty mudstone were part of typical Visco-elastoplastic rheological models. Influenced by the rock rheology, the deformation of surrounding rock presented nonuniform growth trend over time after the tunnel construction. The maximum time-history deformation curves of different depth of tunnel could be divided into three phases. Phase I: linear phase, deformation of linear growth phase took about 55% of the total amount of creep deformation. Phase II: decelerating phase, in this period, the surrounding rock deformation rate got lower and lower while the deformation around the tunnel got stabilized. Phase III: smooth convergence phase, two years after the tunnel add finished, the creep deformation had reached over 90% of the whole, but the slow increase of deformation would still exist for a long time. The ratio of the creep deformation of the three phases was about 5: 4: 1.