LIU Jiangchao, GAO Wenxue, WANG Lintai, CAO Xiaoli, ZHANG Shenghui, WEI Xiao
JOURNAL OF VIBRATION AND SHOCK. 2020, 39(9): 57-62.
Taking the Wen Quan Tunnel as the research background, three kinds of charge structures under hydraulic blasting including the top-water-decking charge structure, two ends-water-decking charge structure and lower-water-decking charge structure were simulated from the views of stress, vibration velocity, dynamic damage and dust after explosion in order to choose the best charge structure.The results show that:(1) The lower-water-decking charge structure is liable to cause rock damage or even breakage at the orifice, resulting in the outflow of explosive gas and reduction of blasting effect.The explosion stress duration in the top-water-decking charge structure and two ends-water-decking charge structure is longer, and it is favorable for surrounding rock fragmentation.Water medium at the bottom of the two ends-water-decking charge structure can protect the surrounding rock of the hole bottom;(2) The blasting vibration speed and stress of the surrounding rock at both ends of the hole can be reduced by using the two ends-water-decking charge structure, so that the energy of the explosive can be fully acted on the surrounding rock of the hole wall to be broken, and explosive consumption can be reduced;(3) The top-water-decking charge structure has the smallest damage to the surrounding rock of the orifice, which causes the larger blocks of rock after breakage.The lower-water-decking charge structure forms the smallest damage area, which results in high explosive consumption.The damage area formed by the two ends-water-decking charge structure is regular, and the rock fragmentation is minimum after blasting;(4) Among the three charg structures, the dust concentration of the lower-water-decking charge structure is the highest after explosion.The dust concentration of the two ends-water-decking charge structure after explosion is slightly higher than that of the top-water-decking charge structure, and the difference is very small.However, the blasting effect of the two ends-water-decking charge structure is better than that of the top-water-decking charge structure.In summary, the two ends-water-decking charge structure is the best and can be used in engineering construction.