Experimental Study On Bearing Characteristics Of Roadway Surrounding Rock-lining Structure Under Alternating Load

In order to address the stability of the perimeter rock-lining combination structure in the lined refuge gas storage space of hard rock roadway of closed coal mine,laboratory tests,physical simulations,theoretical analyses and numerical simulations were conducted to systematically study the fatigue mechanics and postfatigue uniaxial strength characteristics of the combination structure under alternating loads,the strength evolution characteristics of the structural interface with different roughness and fatigue,the stress evolution of the perimeter rock-lining combination structure under high internal pressure,and the stability monitoring of the perimeter rock-lining combination structure in the refuge gas storage space under high internal pressure.The systematic research has been carried out in the areas of stress evolution of lining combination structure under high internal pressure,and the stability monitoring of gas storage space in lined chambers of hard-rock roadways in closed coal mines.(1)Fatigue mechanical characteristics of rock-concrete composite under alternating load.The fatigue mechanical test of rock-concrete composite under different stress conditions was carried out to analyze the fatigue process of the composite specimen and the uniaxial stress-strain relationship after fatigue,and to obtain the influence of alternating load on the strength,modulus of elasticity,instantaneous Poisson’s ratio,volumetric strain and the acoustic emission signal characteristics of the composite specimen.(2)Strength evolution characteristics of rock-concrete composite interface under alternating load.The shear test of rock-concrete composite samples was carried out to analyze the influence of roughness,fatigue degree and normal stress on the shear strength,damage characteristics and evolution characteristics of interface morphology of the composite samples and the mechanism,and three shear damage modes of the composite samples under alternating load were proposed.(3)Microscopic damage mechanism of rock-concrete composite under alternating load.Based on the nuclear magnetic resonance system(NMR)and scanning electron microscope(SEM),the microscopic pore structure of the assembled specimen was monitored before and after the alternating load,and the fatigue damage evolution equations of the rock-concrete assembled specimen under alternating load were established based on the porosity,and the mechanical properties of the assembled specimen were revealed by combining with the experimental process of assembled interfacial strength evolution under the alternating load.The mechanism of deterioration of mechanical properties of the specimen under alternating load is revealed.(4)Developed a large-scale three-dimensional tunnel compressed air energy storage surrounding rock damage and instability simulation model test system.Similar material ratios of conductive concrete are proposed,and with the help of dynamic and static strain acquisition system,distributed fiber-optic measurement system,network parallel electrical testing system and other monitoring means,the evolution characteristics of stress field,deformation field and resistivity field of the perimeter rock and lining structure in the process of gas storage tunnel operation were obtained.(5)Macro-mechanical distribution characteristics of peripheral rock-lining structure under alternating load.Based on the elastic-plastic mechanical analysis of the stress and displacement of the surrounding rock-lining structure of the gas storage roadway under the action of internal pressure,combined with numerical simulation tests,we obtained the macro stress distribution and displacement zoning evolution characteristics of the surrounding rock-lining structure of the roadway under the action of internal pressure,revealed the mechanism of the upper limit of the internal pressure and fatigue on the stability of the surrounding rock-lining structure of the roadway and put forward the idea of the construction of a cloud-based multiparameter stability monitoring platform for the lined caverns of the hard-rock roadway of the closed coal mine gas storage reservoir.The idea of platform construction was proposed.Figure [100] Table [17] Reference [175]...