Shenglong Yang

The mine disaster's essence is the accumulation and release of surrounding rock's energy. By focusing on the full cycle process of rectangular roadway's “excavation-deformation-instability” in a deep non-isobaric stress environment, the mechanical equations of surrounding rock's each part's energy in the elastic/plastic stage are obtained by considering the influence of softening characteristics on the energy evolution. Herein, the mechanical mechanism of deep roadway surrounding rock's energy accumulation-release adjustment is revealed. Based on a specific engineering case, the mechanical derivation process is verified, and the sensitivity analysis for influencing parameters of each part's energy is carried out. The results show that in the elastic stage, the sensitivity ranking is lateral pressure coefficient > initial ground stress > roadway size > supporting force. In the plastic stage, the sensitivity ranking is initial ground stress > lateral pressure coefficient > roadway size > softening modulus > supporting force. The difference between the accumulated energy and the released energy can be defined as the kinetic energy by inducing rockbursts. Combined with the distribution characteristics of the released energy in the roadway side's different parts, the idea of the roadway side's energy release zoning control is formed based on reducing the kinetic energy's goal.

The impact risk evaluation for the strip filling of working faces has always been a research hotspot and a difficulty in the field of rock bursts. In this paper, the concept of the critical filling rate is first proposed, and the criterion for identifying the impact risk of the strip filling of a working face is established. Then, the membership function of coal body stress and the coal seam elastic energy index to impact risk was established, and the classification index of the impact risk grade was formed. On this basis, the overall and local evaluation method of the rock burst hazard for the strip filling of working faces was proposed. Finally, the C8301 working face of the Yunhe coal mine was taken as the engineering background, and the impact risk evaluation was carried out. It was found that the overall risk of the C8301 working face was determined as a strong impact risk, and there were six local risk areas, which included two weak impact risk areas, two medium impact risk areas, and two strong impact risk areas. This study can provide guidance and a reference for the impact risk evaluation of strip-filling mining under the same or similar conditions.

To solve these problems of poor supporting effect and serious deformation and failure of surrounding rock of mining roadway under deep mining stress, a FLAC-3D numerical calculation model is established with −800 m level no. 2424 upper roadway in the Suncun Coal Mine as the background to compare the stress, deformation, and failure law of surrounding rock of mining roadway under once support and multi-level support with the same support strength. It is found that the multi-level support technology has obvious advantages in the surrounding rock of the horizontal roadway on the 2424 working face. From this, the key parameters of multi-level support are determined, and the field industrial test is carried out. The results show that the overall deformation of the surrounding rock is obviously reduced after multi-level support. The displacement of the two sides is reduced by about 40%, the displacement of the roof and floor is reduced by about 30%, and the plastic zone of the roadway is reduced by about 75%. The peak value of concentrated stress decreases from 98.7 MPa to 95.8 MPa, which decreases slightly. The integrity and stability of the surrounding rock are excellent, and the support effect is satisfactory. The research can provide reference and technical support for surrounding rock control of deep high-stress mining roadways.