Numerical Simulation Study on the Anchorage Mechanism of Yield Supporting in Deep Tunnel

In order to study the influence of yield supporting on the zonal disintegration of tunnel surrounding rock under layered lithology in deep tunnel and its anchoring mechanism. Through the analysis of the rock strain/displacement around the tunnel, it’s clear that the combined support form of the rigid lining and the yielding anchor bolt has the best supporting affection in the four supporting forms, which can effectively suppress the zonal disintegration of the deep surrounding rock. At the same time, stress transfer is realized and the zonal disintegration trend of surrounding rock is weakened. Through the analysis of the internal force calculation results of the support structure, it shows that the combined yield supporting structure plays a supporting and anchoring role to the surrounding rock, and realizes the stress distribution, so that the stress field around the tunnel is more uniform. At the same time, the yielding anchor bolt can prevent the failure of the bolt in the deformation because of premature yielding, thus improving the supporting strength of the supporting structure. The research shows that the new combined support structure with rigid lining and pressure/yielding anchor is of great significance for inhibiting/suppressing zonal disintegration of deep rock tunnel.