Combined support technology of segment linings with compressible crushed stone and anchor bolts in layed rock

The segment lining is susceptible to unsymmetrical pressure when a shield tunnel is constructed in deep layered rock. A new support technology of segment linings combined with compressible ceramic and anchor bolts is proposed. In order to study the effect of the support technology, similar model tests are carried out to study the support effect of segment linings with compressible ceramic and anchor bolts with different lengths and spacings. The internal force and deformation of the segment linings are analyzed, and the mechanism of the combined support is revealed from the deformation path of compressible ceramic. The results show that the combined support technology can change the internal force distribution of the segment linings to some extent and can also reduce the biased pressure of the surrounding rock. The application of the bolts can effectively reduce the deformation of the layered rock, and the compressible ceramic can effectively absorb the deformation. There are optimum values of the length and the spacing of the bolts in the combined support, and beyond the values, the reinforcement effect of the bolts will not increase obviously. The mechanism of the combined support consists of two parts: the yielding effect of the compressible ceramic and the reinforcement effect of the bolts. The results of this study have certain reference value for the support design of the shield tunnels in layered rock.