Pressure relief by long horizontal borehole hydraulic fracturing for roadway protection at isolated face stopping line

SUN Yongxin

doi:10.11799/ce202504010

Abstract：Addressing the problem of roadway deformation during the final mining stage of isolated working faces at Wangpo Coal Mine,this study delves into the characteristics of roadway deformation and its influencing factors under the impact of mining activities.It introduces the principle and method of utilizing long horizontal drilling hydraulic pressure relief to protect the roadways.Field application was conducted on the No.3203 isolated working face stopping line at Wangpo Mine.The research discovered that significant deformation rates were evident when roadways were affected by the mining stresses from both flanks working faces,with deformation continually increasing due mainly to the repeated mining activities from both flanks.By conducting long horizontal drilling and regional hydraulic fracturing before the final mining stage to create an artificial weak zone,the method effectively reduces the stress transmission of the overlying rock strata and minimizes the dynamic disturbance impacts on the roadways.Field trial results demonstrate that this pressure relief protection technique significantly decreases the speed and amount of roadway deformation.Within one year,the maximum subsidence in the centralized auxiliary transportation roadway was 30 mm,with a floor heave of 100 mm,and convergence of two ribs at 80 mm.The surrounding rock deformation was greatly reduced and the stress level lowered by approximately 25%,thereby enhancing the stability of the roadway's surrounding rocks and reducing the frequency of maintenance.The research results could have significant implications for ensuring the safe and efficient production of the mine,and offer a scientific foundation and technical support for controlling roadway deformations in similar coal mines.