摘要
露天采场的爆破振动会对邻近隧洞的稳定性产生很大的影响,有必要采用控制爆破的方式来减小爆破振动的危害,保证地下隧洞的安全。考虑到金堆城钼矿南露天采场爆破振动对地下引水隧洞的影响,决定采用预裂爆破的方式控制爆破振动。利用ANSYS/LS-DYNA建立台阶-预裂缝-隧洞模型,对不同预裂缝深度、长度及预裂缝与爆源间距条件下的单孔爆破进行模拟,分析缝后隧洞迎爆面测点峰值振速和测点平均减震率随预裂缝参数变化的规律,拟合平均减震率随预裂缝参数变化的计算公式。研究结果表明:迎爆面边墙中点受爆破振动影响最大,拱顶受到的影响相对较小;预裂缝深超过3 m后才会起到显著的减震效果;结合矿山经济技术条件,得出预裂缝模型的推荐参数:预裂缝深0.7~1.1倍炮孔深度,缝长需超过1倍炮孔深度,缝源间距0.8~1倍炮孔深度,以上参数条件下的平均减震率超过50%。
The blasting vibration of the open pit has a big influence on the stability of adjacent tunnels,it is necessary to reduce the harmful of blasting vibration by adopting controlled blasting technique to ensure the safety of underground tunnel.The pre-splitting blasting technique is adopted to control the basting vibration by considering the influence of blasting vibration of the south open stope to the underground diversion tunnel of Jinduicheng Molybdenum Mine. The bench-presplit crack-tunnel model of the open stope is established by using the ANSYS/LS-DYNA software,to simulate the blasting process under the conditions of different depth and length of pre-splitting crack and the distance between pre-splitting crack and explosion source.Based on the model established in this paper,the change rules of maximum vibration velocity and average damping rate of the measurements points of tunnel blasting face behind pre-splitting crack with pre-splitting crack parameters are analyzed,the calculation formula of the average damping rate changed with pre-splitting crack parameters is fitted. The study results show that：the midpoint of the blasting face is affected by the blasting vibration seriously,while,the influence degree of the blasting vibration to arch crown is relative small; the significance damping effect can be obtained when the depth of pre-splitting crack is more than 3 m. According to the economic and technical conditions of the mine,the recommended parameters of pre-splitting crack model are obtained,the depth of pre-splitting crack is the 0. 7 ~ 1. 1 times of the borehole depth,the length of pre-splitting crack is more than 1 time of borehole depth,the distance between the pre-splitting and explosive source is the 0. 8 ~ 1. 0times of borehole depth,therefore,under the above parameter conditions,the average damping rate can be more than 50%.
出处
《金属矿山》
CAS
北大核心
2017年第9期66-71,共6页
Metal Mine
基金
中央高校基本科研业务费专项(编号:2017IVA048)
关键词
引水隧洞
预裂缝模型
减震率
数值模拟
Diversion tunnel
Pre-splitting crack model
Damping rate
Numerical simulation
