Research and application of empty hole effect of roof cutting energy-gathering blasting in retaining roadway
No.2303 return air roadway of Changcun Mine was taken as the engineering background to study the empty hole effect of roof cutting blasting in retaining roadway.Combined with the theory of elastic mechanics,the mechanical model of empty hole effect was established.It was determined that the maximum tensile stress could be realized in the vertical direction of the connection between the blasting hole and the empty hole.The energy-gathering blasting process achieved better pre-splitting effect than the traditional roof cutting blasting by adding energy-gathering charge,positioning block and other devices.Through the verification and analysis of multi-scheme numerical simulation,it was determined that the empty hole could significantly change the effective stress state near the empty hole,and the closer to the empty hole,the more obvious the blasting effect was.The empty hole could effectively increase the extension length of the main crack,and then increased the distance of the blasting hole.Through the analysis of blasting pre-splitting effect,the reasonable spacing of blasting holes under the action of empty holes was determined to be 800 mm.
万方数据
维普
