掘进机法与钻爆法施工隧道围岩扰动特性对比研究

Comparative Study of Surrounding Rock Disturbance Characteristics of Tunnel Construction with Cantilever Roadheader Method and Drilling and Blasting Method

为揭示地铁隧道悬臂掘进机法施工和钻爆法施工过程中围岩力学效应和变形扰动特性差异,以贵阳轨道交通3号线拟建黔灵山公园站-北京路站区间暗挖隧道为依托,借助有限元软件对Ⅴ级围岩采用悬臂掘进机法和钻爆法两种方法施工过程围岩位移场、扰动区、锚杆应力等进行对比分析。结果表明:爆破法施工时,围岩变形最大值为343.29 mm,约为悬臂掘进机法的22倍,围岩扰动区亦远大于悬臂掘进机法施工。对支护结构进行分析发现,悬臂掘进机法施工锚杆最大拉应力约为爆破法施工的92.7%,初支最大压应力约为爆破法施工法的48.0%,表明悬臂掘进机法施工可以明显减小锚杆和初支应力,降低破坏风险,验证了悬臂掘进机法施工相较于爆破法施工在减小围岩扰动方面的优越性。

In order to reveal the mechanical effects and deformation disturbance characteristics of surrounding rocks during the construction processes of cantilever roadheader method and drilling and blasting method in metro tunnel projects,a comparative analysis was conducted using the finite element software based on the construction of a tunnel section between Qianlingshan Park Station and Beijing Road Station on the proposed Guiyang Rail Transit Line 3.The comparative analysis focused on the displacement field,disturbance area,and anchor bolt stress of the surrounding rocks in grade V rock conditions under cantilever roadheader method and drilling and blasting method.The results show the following:the maximum deformation of the surrounding rock is 343.29 mm,which is about 22 times that of the cantilever roadheader method.The disturbance area of surrounding rock is also much larger than that of cantilever roadheader method.The analysis of support structure shows that in cantilever roadheader method excavation of grade V rock,the maximum tensile stress of the anchor bolt is approximately 92.7%of that in drilling and blasting method,and the maximum compressive stress on the initial support is approximately 48.0%of that in drilling and blasting method.This indicates that cantilever roadheader method can significantly reduce the stress on the anchor bolt and initial support,reducing the risk of damage.It confirms the superiority of cantilever roadheader method over drilling and blasting method in reducing disturbance to the surrounding rocks.