| Geological rock masses contain a large number of discontinuous structural surfaces such as joints,fractures and faults.The presence of these discontinuities undermines the integrity of the rock mass,and the presence of joints in the rock mass can often lead to the opening,closing and slipping of structural surfaces within the rock mass,which can be very damaging to the structural stability of the rock mass.As the depth of coal mining increases,especially when faced with a complex environment under high ground stress,there are still many problems to be solved in the rupture evolution mechanism and stability control of the intermittent jointed surrounding rocks in deep roadways.In this thesis,we take the Xin’an coal mine-600 m north wing road as the engineering background,and use the "deep underground engineering structural instability whole process simulation test system" developed by the subject group,based on the vibration and electromagnetic multi-source information monitoring physical model test system,numerical simulation and field practical engineering application and other comprehensive research methods.The research is based on a comprehensive research method,such as a physical model test system for monitoring seismic and electromagnetic multi-source information,numerical simulation and practical engineering applications.The main research contents and results are as follows:(1)Based on the principle of similarity theory,the physical and mechanical similarity materials of coal rock in engineering background were simulated and developed,prefabricated intermittent jointed surround rock casting moulds were developed,large-scale geological model tests of intermittent jointed surround rock under different supports were carried out based on vibration and electromagnetic multi-source information monitoring,the corresponding load-displacement curves of intermittent jointed surround rock rupture evolution were obtained,and the load-displacement curves of intermittent jointed surround rock rupture evolution under different anchorage structures were investigated.The evolution characteristics of fracture field,stress field and displacement field in the process of fracture of intermittent jointed surrounding rocks under different anchorage structures were investigated,and the mechanism of macroscopic disaster evolution of intermittent jointed surrounding rocks was revealed.(2)Based on the results of physical simulation tests,a two-media-four-interface model of the coal rock body was established using the PFC 2D particle flow numerical simulation program,and the fine-scale expression and stress evolution law of the anchored fracture surrounding rock were obtained,revealing the fine-scale mechanism of the fracture evolution of the intermittent jointed surrounding rock and the anchorage mechanism and failure mechanism of the relevant support conditions,and exploring the macroscopic mechanical characteristics and structural evolution of the anchorage structure of the intermittent jointed surrounding rock.(3)By introducing the distribution of cracks,the structure of the anchorage structure is discussed.(3)By introducing the fractal dimension of crack distribution and constructing a fractal model to characterize the degree of structural damage according to the crack distribution characteristics of the whole bearing process of the surrounding rock of the roadway,the fractal model quantifies the crack distribution of the intermittent jointed surrounding rock,quantitatively and qualitatively analyzes the damage of the surrounding rock,and proposes the composite support scheme of "anchor network and rope spraying + 36U-shape shed + deep and shallow hole high and low pressure coupled grouting".The composite support scheme of "Anchor Mesh Spraying + 36U-Shed + Deep and Shallow Hole High and Low Pressure Coupled Grouting" was proposed and industrial tests were carried out in the roadway with good results.There are 41 figures,16 tables and 69 references in this thesis. |
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