既有溶洞岩体爆破装药结构优化及数值模拟

为降低溶洞等不良地质条件对于台阶爆破作业的负面影响,基于既有溶洞露天爆破作业工况,运用 AUTODYN 数值仿真软件,建立二维有限元模型,针对孔身、孔底、孔间溶洞模型进行装药结构优化及仿真分析,重点对比 分析了不同模型岩体损伤、孔壁压力和飞石速度差异。 结果表明:对于孔身溶洞,相较于普通 PVC 管装药结构,采用 尼龙编织袋装药爆破可有效提高爆炸冲击波对孔壁的压力,降低大块率,改善岩体松动效果;孔底溶洞采用底部填塞 +上部装药外加台阶底部钻水平孔装药方式,可有效破除残留根底;对于贯通型孔间溶洞,采用底部装药+中间填塞+ 上部装药+顶部填塞的分段装药结构,并在前排钻辅助孔进行孔底装药,可有效改善岩体损伤破碎效果。

Optimization of Charging Structure and Numerical Simulation of Blasting of Rock Mass Containing Karst Cave

In order to reduce the negative impact of unfavorable geology such as karst caves on bench blasting,based on the working conditions of open-pit blasting of existing karst caves,a two-dimensional finite element model is established by using AUTODYN numerical simulation software. The charging structure optimization and simulation analysis are carried out for the cave models of hole body,hole bottom and inter-hole,and the differences of rock mass damage,hole wall pressure and flying rock velocity of different models are emphatically compared and analyzed. The results show that compared with ordinary PVC pipe charging structure,charging blasting with nylon woven bags can effectively improve the impact of explosion shock waves on holes. The karst cave at the bottom of the hole adopts the method of " bottom filling+upper charging" plus horizontal hole drilling at the bottom of the step to charge,which can effectively break the residual root bottom;For the through-hole karst cave,the sectional charging structure of " bottom charging+middle filling+upper charging+top filling" is adopted,and the auxiliary holes are drilled in the front row for hole bottom charging,which can effectively improve the damage and crushing effect of rock mass.