The Damage Mechanism Research And Application Of Stope Bottom Structure Under Impact Loads

The bottom structure of underground stope is an important project for ores accepting and ore-drawing, which directly affects the ores recovery in terms of safety, economy and efficiency. Closely combined with the project named the application and study of Dongguashan Copper Mine cavity monitoring technology, adopt the field monitoring, theoretical analysis and numerical simulation comprehensive means to do research on the damage mechanism of bottom structure, and try to find the damage reducing measures. The main contents are as follows:(1) For the engineering practice that substantial amount of residual ores caused by the serious damaged bottom structure are difficult to be fully recovered, adopt the digital means (CMS and Surpac etc.) to get the damage information of bottom structure and construct three-dimensional visual model; By analyzing the damage of bottom structure, the main damage types of bottom structure were obtained; Do statistics of residual ores.(2) On the basis of analyzing the shock wave propagation in rock mass, carry out the research on the propagation of oblique incidence caused by ores, and then get the conclusion that the damage of bottom structure has related to the slope angle, and when the angle is about45°the compression-shear coupling damage gets most; By analyzing the dynamic model of bottom structure, preliminary revealed the damage mechanism that the accumulated plastic strain causes the bottom structure damage.(3) Using the damage mechanics principle to carry out the research on the damage evolution of anisotropic elasto-plastic rock mass when under impact loads, from the microscopic view reveals damage evolution law of bottom structure; Using fracture mechanics theory to do the research on the damage accumulation and cracks development of rock mass when under frequent impact loads, from a macroscopic perspective, reveals the dynamic damage accumulation and failure mechanism of bottom structure rock mass subjected to frequent impact loads caused by blasted ores. (4) Based on the above damage mechanism analysis of bottom structure, the damage reducing measures (optimized slope angle, anchors supporting) were proposed. Then, numerical simulations were done to verify those measures. The results show that increase the slope angle of bottom structure and use bolts to support the bottom structure can reduce the compression-shear coupling damage of it.This thesis takes the lead in the stope bottom structure impact damage mechanism study, preliminary revealed the damage rule of stope bottom structure which subjected to the impact loads and proposed the technical measures to reduce stope bottom structure damage. Research results for reducing mine stope remnant ore, improving recovery rate of resources, and achieving safe, efficient resource recycling have important realistic significance.