Geomechanical Model Test and Energy Mechanism Analysis of Zonal Disintegration in Deep Surrounding Rock

With the decreasing of shallow resources, underground roadways of resources exploitation have reached into deep rock mass with high geostress. A series of new failure phenomena such as zonal disintegration phenomenon were discovered in deep surrounding rock, which is completely different from shallow caverns. To reveal the formation mechanism of zonal disintegration, the geomechanical model test and energy mechanism analysis of zonal disintegration were carried out respectively. Taking the deep roadway of Dingji coal mine in China's Huainan coal mine as engineering background, a 3D geomechanical model test was carried out relying on the high stress 3D loading test system. The zonal disintegration phenomenon was observed, and the oscillation law of displacement was measured. Based on the strain gradient theory and continuum damage mechanics, the elastoplastic damage model was established. An energy failure criterion was proposed by principle of energy dissipation and release. The ODE45 function in Matlab software was used to solve the displacements and stresses of excavated model roadway. The analytical solutions the and the geomechanical model test were basically consistent. The applicability of theoretical model and energy failure criterion were confirmed to explain the mechanism of zonal disintegration and it can be used to provide theoretical support for the failure and supporting design of surrounding rock in deep underground engineering.