爆炸载荷作用下临界震塌爆距公式研究

Formula Research on Critical Collapse Distance Subjected to Blasting Loading

坑道震塌破坏机制复杂,是工程中亟待解决的难题之一。为了得到便于工程应用的临界震塌爆距计算公式以及影响临界震塌爆距的主要因素,在常用经验公式的基础上,通过拟合爆距与洞跨比影响系数,将经验公式显化,推导的修正公式不需要反复迭代试算,使用方便。利用ANSYS/LS-DYNA有限元分析软件对坑道正上方装药爆炸进行数值模拟,得出临界震塌爆距,其结果与修正公式相比较,表明修正公式与模拟结果吻合较好,可用于临界震塌爆距的计算。数值模拟临界震塌爆距随洞室跨度的变化,结果表明:洞室跨度越大,临界震塌爆距越大,且趋于某一极限值;洞室跨度小于15 m时临界震塌爆距随洞跨的增大增幅较快。

The mechanism of tunnel collapse is complex as a difficult issue to be solved urgently in engineering. In order to get the critical collapse distance formula convenient for engineering application and the main factors influ- encing the critical collapse distance, on the basis of common empirical formula, the influence coefficients of ratio of collapse distance and tunnel span is fitted and the empirical formula is provided, which needs no further iterative cal- culation. The finite element analysis software for ANSYS/LS-DYNA is used to simulate the explosion above the tun- nel in rock mass to get the critical collapse distance. The simulation results are compared with the calculation results from the revised formula. The revised formula put forwards in this work agrees well with the simulation results and can be used to calculate the critical collapse distance. Numerical simulation is used to analyze the critical collapse distance variation with underground cavern spans. The results show that the larger the tunnel span, the larger the crit- ical collapse distance,which tends to be a certain limit. The critical collapse distance increases rapidly with the un- derground cavern span when the span is less than 15 meters.