Determination of rock resistant coefficient in lining tunnels based on SMP failure criterion

According to the viewpoint of load, it is very important to consider the common bearing and the secondary stress functions caused by excavating for the surrounding rock and lining. Based on the spatially mobilized plane (SMP) failure criterion, the formula for calculating rock resistant coefficient is given. It can be adopted to consider the intermediate principal stress effect. Through changing the internal friction
and the cohesion
of the physical mechanics nature for the tunnel rock, it is shown that considering the influence of the intermediate principle stress can enhance the rock resistant coefficient of the lining tunnels compared with the rock resistant coefficient by using the Mohr-Coulomb failure criterion. So the rock resistant coefficient of the lining tunnels has certain practical significance based on the SMP failure criterion of the cohesion materials.