岩质隧道机械胀裂数值模拟分析

Numerical Simulating Analysis of the Rock Drill-splitter in the Tunnel Excavation

复杂环境下岩质隧道钻爆法施工将产生安全隐患。机械胀裂法利用岩石抗拉强度低的特点,以其有效的可控性和安全性,近年来在复杂环境下隧道开挖中得到越来越广泛应用。本文通过数值计算方法,模拟分析了岩质隧道机械胀裂全过程,得到如下结论:(1)针对III级围岩隧道开挖,采用钻孔间距0.7~0.75m、抵抗线0.5~0.6m,胀裂力150~160MPa等施工技术参数,可以有效保证胀裂效果;(2)通过比较相邻孔间切向应力值与岩石抗拉强度的大小来判断胀裂是合理的;(3)机械胀裂均会在保留岩体中产生一定程度的损伤,后续作业调整施工参数,即增大钻孔间距和抵抗线,减小胀裂力,可有效完成岩质隧道胀裂开挖作业。

Safe hidden trouble will be produced by blasting method in the tunnel excavation under complicated environment. The rock drill-splitter is more and more widely used in the tunnel excavation because of the controllabilityand environmental protection. Based on the finite element software midas GTS,the whole process of splitting is simulating in this paper,and the conclusions are as follows:(1)For level III surrounding rock tunnel excavation,the use of borehole spacing is0. 7 ~ 0. 75 m,resistance line is 0. 5 ~ 0. 6m,burst strength is 150 ~ 160 MPa,which can effectively guarantee the burst effect;(2)By comparing the stress value on the middle of the drilling and the tensile strength to determine the effect of the rock burst is feasible and reasonable;(3)Burst operation will produce different degrees of injury in the context of the reserved rock mass,so construction parameters should be adjusted,namely,increasing the hole spacing and resistance line,reduce the burst strength,and the rock tunnel can be cracked efficiency.