Deformation Characteristics and Determination of Optimum Supporting Time of Alteration Rock Mass in Deep Mine

In the tectonic belt, the stability of surrounding metamorphic rock was studied systematically using field investigation, laboratory analysis, theoretical derivation and engineering application. Based on the Jinchuan Mine geological conditions, the exposed surrounding rock of the roadway and its deformed features were analysed. The results of X-ray diffraction and scanning electron microscopy shows that the microstructures of altered rocks affected by structural belts were significant loose, the fractures and pores were well developed, and the composition of clay minerals was more abundant. Then, A nonlinear rheological constitutive model based on the modified Nishihara model is deduced. The actual monitoring data and the rheological parameters of the surrounding rock mass in the Jinchuan Mine area were determined. And these data were used to obtain the optimum secondary-support time by inverse analysis. Finally, the joint support technology of bolt and anchor cable was proposed. The field practice shows that this support method is favourable to the long-term stability of roadway and can effectively reduce the deformation of roadway surrounding rock.