大断面隧道揭急倾斜突出煤层临界安全岩柱厚度

Critical Safety Rock Pillar Thickness of Large Cross Section Tunnel Excavating Steeply Inclined and Outburst Coal Seam

为了降低公路隧道大断面石门揭煤的施工风险,以松坎隧道穿越急倾斜煤层施工为工程依托,采用理论手段估算了安全岩柱的厚度,并结合工程现场分析了开挖过程中的围岩破坏特征,从塑性变形与应力分布2个角度提出了对应的岩石破坏判据.采用FLAC^(3D)软件建立了隧道穿越急倾斜煤层施工的三维模型,对比分析了掌子面前方距煤层不同位置的塑性破坏特征与应力分布规律.根据研究结果并充分考虑隧道现场情况,最终选择9 m作为松坎隧道穿越急倾斜突出煤层施工的安全岩柱厚度.

In order to reduce the construction risk of uncovering coal at large cross-sections of highway tunnels,based on the construction of Songkan tunnel crossing steep coal seam,the thickness of safety rock pillar was estimated by theoretical means,and the failure characteristics of surrounding rock in the excavation process combination with the engineering site.Corresponding rock failure criteria were proposed from the perspectives of plastic deformation and stress distribution.The three-dimensional model of tunnel construction through steeply inclined coal seam was established by using FLAC^(3D )software,and the plastic failure characteristics and stress distribution law at different positions in front of the face of the tunnel were compared and analyzed.Research results show that the value of safe rock pillar should not be less than 9 meters for construction of Songkan tunnel crossing steep inclined outburst coal seam.