Temporal and Spatial Evolution of Microcracks in Surrounding Rocks of Roadway Under Blasting Disturbances
Roadway failure triggered by repeated blast disturbances is a common phenomenon in deep metal mines.Investigation on the development of microcracks in the surrounding rock around the roadway is helpful in optimizing the support parameters.In this study,the numerical simulation and experimental study of the dynamic expansion of microcracks were performed by using discrete element software and acoustic emission(AE)monitoring technology,respectively.The relationships between the microcracks response characteristics of the surrounding rocks around the roadway with the stress distribution and blasting disturbance parameters were revealed.The results show that the direction of the principal stress affects the initial spatial distribution of the excavation damage zone and the dominant crack types.In addition,blast disturbance mainly promotes the expansion and penetration of the microcracks,aggravating the damage to the roadway.Especially,where the ratio of the length of the waveform to the span of the roadway is approximately 1,the degree of microcrack extension in the sidewalls facing the blast is significantly greater than that in other areas.In the absence of radial stresses or under small radial constraints,the blast disturbance stress waves can easily lead to tensile fracture in the direction of the principal stress and the sidewalls facing the blast.Therefore,when determining the support measures for deep roadways,the differences in crack response characteristics caused by stress distribution and blast disturbance parameters should be considered comprehensively.
万方数据
维普
