Target stratum determination in surface hydraulic fracturing for rock burst prevention in deep mines under hard and thick roof strata

XU Gang; ZHANG Zhen; LIN Xingyu; LU Chuang; ZHANG Chunhui

doi:10.11799/ce202510001

Abstract：Surface hydraulic fracturing is a new technology for preventing rockburst in deep mines with hard and thick roof strata in Inner Mongolia-Shaanxi mining area.Determining the target stratum is crucial for the surface fracturing implementation.Based on the positional relationship between the hard and thick roof strata and the caving zone in the working face,two types of bearing structures were proposed,and the corresponding bearing mechanical models for the hard-thick roof were established.The calculation methods for the hard and thick roof rupture interval,the rupture energy release and transmission were given.The mechanical failure criterion of rock burst in coal roadway caused by roof rupture was provided.Combining with practices of surface hydraulic fracturing for rockburst prevention in the Binchang and Dahaize mining area,the method of identifying target rock stratum for surface hydraulic fracturing was proposed based on the fracturability,the disaster potential of energy transfer,and the position of the rock stratum.The method was adopted in the No.401102 working face of Mengcun Coal Mine.The results showed that:the target stratum for surface fracturing at the working face were the coarse sandstone layers at 65.95 m and 99.31 m away from the coal seam,respectively.After fracturing the target stratum with the surface fracturing wells.The periodic weighting interval,mine pressure duration and intensity,total microseismic frequency,and total released energy in the working face and coal roadway in hydraulic fracturing area all declined significantly,and the surface fracturing achieved favorable effect.The proposed method was proved reasonable,and provided a calculation method to determine the target stratum for surface fracturing.