深埋引水隧洞光面爆破周边孔装药结构优化试验研究

Optimization of Charging Structure of Surrounding Holes in Smooth Blasting of Deep Diversion Tunnel

隧洞爆破周边孔不连续装药结构是影响光面爆破效果的重要因素之一。基于秘鲁圣加旺Ⅲ水电站引水隧洞工程,针对现场爆破施工方案超挖现象,采用ANSYS/LS-DYNA建立周边孔不连续装药结构数值计算模型,分析了不同药卷间距下周边孔模型的围岩爆破效果;选择最优的周边孔装药结构设计方案开展现场爆破试验,对比验证了装药结构设计对隧洞超挖的改善效果。结果表明:当周边孔药卷间距小于350 mm时,爆破不会出现欠挖现象,且超挖范围随着药卷间距的增大而减小;当周边孔药卷间距大于400 mm时,爆破效果开始出现欠挖现象,且随着药卷间距的增大,欠挖范围增大。通过数值模型对比分析得出周边孔的最优药卷间距为350 mm,采用优化后的爆破设计方案进行爆破试验,得到的超挖范围明显减小,最大超挖距离由43 cm降至30 cm。

The distance between explosive roll of surrounding hole is one of the important factors affecting the effect of smooth blasting.Based on the diversion system project of hydropower station in Peru,this paper introduced the blasting design scheme of the project and evaluated the blasting effect.The peripheral hole model under different charge structures was established by ANSYS/LS-DYNA to analyze the blasting effect of the surrounding hole model on rock.At last,the optimal design scheme of surrounding hole is selected for blasting test,so as to improve the over excavation and under-excavation phenomenon of the project.The results show that when the distance is less than 350 mm,the under-excavation will not appear and the over excavation range decreases with the increase of the distance between the surrounding holes.When the distance is more than 400 mm,the under-excavation begins to appear in the blasting effect and increases with the increase of the distance.Through the comparative analysis of the numerical model,it is concluded that the optimal charge spacing of the surrounding hole is 350 mm.The optimal design scheme is adopted for the blasting test.It is obtained that the overbreak range is significantly reduced,and the maximum distance is reduced from 43 cm to 30 cm.