Microseismic(MS)event locations are vital aspect of MS monitoring technology used to delineate the damage zone inside the surrounding rock mass.However,complex geological conditions can impose significantly adverse ef...Microseismic(MS)event locations are vital aspect of MS monitoring technology used to delineate the damage zone inside the surrounding rock mass.However,complex geological conditions can impose significantly adverse effects on the final location results.To achieve a high-accuracy location in a complex cavern-containing structure,this study develops an MS location method using the fast marching method(FMM)with a second-order difference approach(FMM2).Based on the established velocity model with three-dimensional(3D)discrete grids,the realization of the MS location can be achieved by searching the minimum residual between the theoretical and actual first arrival times.Moreover,based on the calculation results of FMM2,the propagation paths from the MS sources to MS sensors can be obtained using the linear interpolation approach and the Runge–Kutta method.These methods were validated through a series of numerical experiments.In addition,our proposed method was applied to locate the recorded blasting and MS events that occurred during the excavation period of the underground caverns at the Houziyan hydropower station.The location results of the blasting activities show that our method can effectively reduce the location error compared with the results based on the uniform velocity model.Furthermore,the obtained MS location was verified through the occurrence of shotcrete fractures and spalling,and the monitoring results of the in-situ multipoint extensometer.Our proposed method can offer a more accurate rock fracture location and facilitate the delineation of damage zones inside the surrounding rock mass.展开更多
Based on the natural characters of stratum, complicated geological mining conditions and the essence of mining rock mass destruction, the complexity of rock mass destruction caused by miningw as analyzed. The inner li...Based on the natural characters of stratum, complicated geological mining conditions and the essence of mining rock mass destruction, the complexity of rock mass destruction caused by miningw as analyzed. The inner link between rock mass destruction phenomena caused by mining and nonlinear science was revealed. There are numerous cracks in natural rock mass. The cracks’ distribution is irregular and is of statistical fractal structure. Self-organizational nonlinear evolution of the inner structure flaws leads to the rock mass destruction with external force. The evolution includes single fault’s fractal development, formation and evolution of fractal crack network and coordination of fractal crack network, etc. The law of fractal crack network’s evolution was introduced, at the same time, the coordination of fractal crack network was analyzed. Finally, based on coordination the principal equation of mining-caused subsidence of structural rock mass was established and its steady-state solution and unsteady-state solution were found.展开更多
基金the Key Program of National Natural Science Foundation of China(52039007)for providing financial support.
文摘Microseismic(MS)event locations are vital aspect of MS monitoring technology used to delineate the damage zone inside the surrounding rock mass.However,complex geological conditions can impose significantly adverse effects on the final location results.To achieve a high-accuracy location in a complex cavern-containing structure,this study develops an MS location method using the fast marching method(FMM)with a second-order difference approach(FMM2).Based on the established velocity model with three-dimensional(3D)discrete grids,the realization of the MS location can be achieved by searching the minimum residual between the theoretical and actual first arrival times.Moreover,based on the calculation results of FMM2,the propagation paths from the MS sources to MS sensors can be obtained using the linear interpolation approach and the Runge–Kutta method.These methods were validated through a series of numerical experiments.In addition,our proposed method was applied to locate the recorded blasting and MS events that occurred during the excavation period of the underground caverns at the Houziyan hydropower station.The location results of the blasting activities show that our method can effectively reduce the location error compared with the results based on the uniform velocity model.Furthermore,the obtained MS location was verified through the occurrence of shotcrete fractures and spalling,and the monitoring results of the in-situ multipoint extensometer.Our proposed method can offer a more accurate rock fracture location and facilitate the delineation of damage zones inside the surrounding rock mass.
基金Foundatinitem Project(50274044) supported by the National Natural Science Foundation of China .
文摘Based on the natural characters of stratum, complicated geological mining conditions and the essence of mining rock mass destruction, the complexity of rock mass destruction caused by miningw as analyzed. The inner link between rock mass destruction phenomena caused by mining and nonlinear science was revealed. There are numerous cracks in natural rock mass. The cracks’ distribution is irregular and is of statistical fractal structure. Self-organizational nonlinear evolution of the inner structure flaws leads to the rock mass destruction with external force. The evolution includes single fault’s fractal development, formation and evolution of fractal crack network and coordination of fractal crack network, etc. The law of fractal crack network’s evolution was introduced, at the same time, the coordination of fractal crack network was analyzed. Finally, based on coordination the principal equation of mining-caused subsidence of structural rock mass was established and its steady-state solution and unsteady-state solution were found.
