Analysis of Microscopic Mechanical Properties of Conglomerate Based on Nanoindentation Technology

In order to reveal the microstructure control mechanism of the thick conglomerate layer in the process of rock burst inoculation and occurrence in Yima mining area, the mineral composition, cementation structure and micromechanical characteristics of typical conglomerate samples were systematically analyzed based on scanning electron microscope (SEM) and nanoindentation technology. The results show that the conglomerate in this area is densely cemented and the particles are closely arranged. The cements are mainly clay minerals, and some areas are associated with calcite and iron cements. The micro-fractures are developed along the particle boundary and the interface of the cement, showing a certain structural brittleness. The nanoindentation test reveals that there are obvious differences in mechanical properties of conglomerate in different micro-intervals, reflecting its heterogeneity and anisotropy characteristics at the micro-scale. The heterogeneity of microstructure and fracture development characteristics can easily lead to local stress concentration, which is one of the important microscopic factors inducing rock burst. The research results reveal the material basis and evolution mechanism of conglomerate rock burst disaster from a micro perspective, and provide theoretical support for the accurate identification and effective prevention and control of rock burst in extremely thick conglomerate strata in Yima mining area.