超前支护对软岩隧道空间变形的影响分析  

Analysis on Impact of Advanced Support on Space Deformation of Tunnel in Soft Rock Mass

作　　者：洪开荣[1] 杨朝帅[1] 李建华[1] 

机构地区：[1]中铁隧道集团有限公司,河南洛阳471009

出　　处：《地下空间与工程学报》2014年第2期429-433,440,共6页Chinese Journal of Underground Space and Engineering

基　　金：铁道部科技研究开发计划重大课题(2011G004)

摘　　要：软岩大断面隧道施工中掌子面的挤出位移及其前方的先行位移对开挖稳定性影响很大,因此以某软弱围岩铁路隧道大断面施工为例,针对两种预支护加固——掌子面玻璃纤维锚杆预加固和管棚超前支护,设定了5种计算工况,分别进行了开挖过程中掌子面前方的先行位移、掌子面挤出位移和掌子面后方最终位移变化的三维数值模拟,并考察了相应塑性区的分布情况,结果表明:管棚超前支护对最终位移和先行位移有明显的控制作用,掌子面超前玻纤锚杆加固对先行位移有一定的控制作用,但对最终位移的控制作用不明显;与管棚超前支护相比,掌子面锚杆加固对掌子面的挤出变形的控制作用更明显;超前管棚支护更能抑制拱部上方围岩塑性区的发育,而掌子面锚杆加固对抑制超前核心土塑性区发育的效果更好。The influence of extrusion and pre-displacements of tunnel face on excavation stability is quite large during tunnel construction in soft rock mass. So, taking a railway tunnel with large-section constructed in soft rock mass as an example, five calculating cases were designed for two kinds of pre-supporting and reinforcement rein- forcement of rock bolts on tunnel face and advanced pipeshed support suggested by the authors. The 3D numerical computation for the change of pre-displacement, extrusion and ultimate displacement during excavation was carried out, and the distribution of corresponding plastic zones was analyzed. The results show as follows： The pre-displace- ment and the ultimate displacement are controlled obviously by advanced pipeshed support. The controlling effect of rock bolts of tunnel face on pre-displacement is a little better while it is not obvious on ultimate displacement. It is better for controlling of extrusion deformation by rock bolts on tunnel face than that by advanced pipeshed support. The plastic zone above arch is well controlled by advanced pipeshed support while the one of advanced core soil is ef- fectively controlled by rock bolts on tunnel face.

关 键 词：软弱围岩 超前预加固 大断面施工 挤出变形 

分 类 号：U451[建筑科学—桥梁与隧道工程]