Quantitative Characterization of Energy Consumption Characteristics for Impact Fracture of Green Sandstone Based on PFC2D Particle Flow Simulation
The impact loading affects the stability of rock mass.Currently,research of rocks mainly focuses on the characteristics of macro failure and laws of energy evolution,and most of them belong to qualitative research,lacking quantitative characterization at the microscopic level.In order to deeply study quantitative characterization of energy consumption characteristics for impact fracture of green sandstone,the macro-micro relationship of mechanical response in green sandstone was established by combining the laboratory tests and microscopic parameter calibration,and the fracture characteristics,crack number,fracture time and utilization efficiency of energy in green sandstone were analyzed under different instantaneous impact rates.The results show that the fracture characteristics of green sandstone can be divided into localized,extended and intensified fracture modes;the crack extension pattern of the green sandstone presents bottom initiation,X-shaped conjugate ramp,and intensive extension modes;the crack extension time changes from rapid increase to gradually slow down,and the average value is 275μs;the utilization efficiency of fracture energy in green sandstone is divided into the stages of slow increasing,rapid increasing and stable increasing,with the maximum utilization efficiency of fracture energy 10.851％.At the same time,the quantitative relationship between the number of destructive micro-unit,the total number,the generation time of cracks,utilization efficiency of fracture energy and the instantaneous impact rate of green sandstone was obtained through fitting.The research results can provide reference for the reasonable selection of parameters in the crushing process of rock.
rock mechanicsgreen sandstoneparticle flow simulationimpact loadingfracture energyinstantaneous impact rateutilization efficiency of energy
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