关键词: 预裂爆破　, 数值模拟　, 孔间距　, 大直径导向孔　, 应力集中　, 爆破振动

Abstract: In pre-splitting blasting,the large diameter guide hole has obvious guiding effect on the generation and propa gation of cracks between holes.When this blasting technology is applied,the hole spacing is an important parameter affecting the blasting effect.In order to determine the optimal hole spacing of large diameter guide hole pre-splitting blasting,the calcu lation models of four groups of working conditions with charge hole diameter of 120 mm,guide hole diameter of 165 mm and hole spacing of 1.3 m,1.1 m,0.9 m and 0.7 m were established.The numerical simulation results indicate that a high-stress re gion forms near the guide hole due to the superposition of stress waves.As the distance between holes decreases,both the extent of the high-stress area and the maximum equivalent stress value steadily increase,along with a corresponding rise in the damage value and range along the hole connection line.When the hole spacing is less than 0.9 m,there are many cracks between holes, and the crack damage value is greater than 0.5.At this time,the stress peak value of each measuring point has exceeded the dy namic tensile strength of the rock,and penetrating cracks can be formed on the hole connection line.In order to further verify the accuracy of the numerical simulation results,the blasting test was carried out.The results show that when the hole spacing is less than 0.9 m,the hole mark rate of the half-wall hole after blasting is more than 90%,and the unevenness is less than 15 cm.When the hole spacing is from 1.1 m to 0.9 m,the blasting vibration velocity decreases most obviously,with an average decrease of 14.1%.It shows that the cracks between the holes are fully penetrated when the hole spacing is 0.9 m,which pro duces a good shock absorption effect,provides a basis for the pre-splitting blasting design of large-diameter guide holes.