Abstract: It is of great significance to ensure the pre-splitting blasting effect in the jointed fracture zone in the mine side support operation.In order to solve the problems of poor pre-splitting blasting effect and low half-wall hole rate of complex broken rock mass， taking the west side of Xigou Limestone Mine of Jiuquan Iron and Steel Group Co.， Ltd. as an example ，combined with the characteristics of blasting holes and construction technology， a rectangular shaped charge device with an angle of 85° and an air interval of about 13 mm between the charge column and the hole wall was proposed， the directional rock breaking mechanism of the shaped charge jet was analyzed.ANSYS/LS-DYNA numerical model was established， and the stress of the monitoring points along the horizontal and vertical directions of the energy accumulation tank was extracted and analyzed.The analysis results show that due to the existence of the energy accumulation charge，the stress distribution of the rock mass around the blast hole was adjusted.Under the same distance with the hole wall， the stress along the horizontal direction of the center of the blast hole was significantly greater than that along the vertical direction of the center of the blast hole， and the former was 1.62~3.51 times that of the latter. The explosion energy fully acted on the direction of the energy accumulation tank， so that the energy along the vertical direction of the center of the blast hole， i. e.，the direction of the protected rock masswas weakened， and the effect of the energy accumulation seam was effectively improved.Further field test results show that the half-wall hole rate of pre-splitting blasting area with rectangular shaped charge is 64%~82%，and the unevenness is less than 20 cm，which is far better than that of ordinary pre-splitting blasting.The feasibility of rectangular shaped charge structure is verified，which has certain reference significance for similar mines.

Key words: mine blasting, rectangular shaped charge device, pre-splitting blasting, half wall hole, field test