Insight into the mechanism of roadway protection against high advance stress by roof pre-splitting
To ensure the stability of the underground structures,such as roadways that are ex-posed to high mining-induced stress in Guqiao Coal Mine,an approach known as roof pre-split-ting(to stop the stress transfer)is proposed to ensure the stability of roadways at No.1311(1)working face after theoretical analysis and on-site monitoring.The results show that the struc-ture'cantilever plate'is the major cause that leads to high stress at the working face.By es-tablishing a mechanical model of the overlying rock strata,an equivalent stress is used to re-flect the high-stress-bearing capacity of the coal seam,and the stress transfer mechanism inside the overlying strata is revealed as well.Therefore,to make sure the stability of the road-way,the cantilever plate within the disturbance range of mining activity should be cut off in time to stop the high stress from transferring.Given this condition,a blasting method along the roadways is put forward to relieve the high stress.Besides,it can block the transmission of stress as expected.Moreover,the parameters of deep-hole blasting with heavy-duty grain col-umns are provided.The application turns out that the effects of roof cracking and stress relief with roof pre-splitting are significant.
roof pre-splittingroof cutting and pressure releasingstress barrierblasting cut-tingequivalent stress
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