超前支护对软岩隧道空间变形的影响分析

发布时间：2018-06-07 14:30

本文选题：软弱围岩 + 超前预加固　；参考：《地下空间与工程学报》2014年02期

【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。
[Abstract]:In the construction of large section tunnel in soft rock, the extrusion displacement of the face and the advance displacement in front have a great influence on the stability of excavation. Therefore, taking the large section construction of a railway tunnel with weak surrounding rock as an example, In view of two kinds of pre-support reinforcement, the pre-reinforcement of face glass fiber bolt and the advance support of pipe shed, five calculation conditions are set up, and the advance displacement of the front of the face of the palm during excavation is carried out respectively. Three-dimensional numerical simulation of extrusion displacement and final displacement behind palm face is carried out, and the distribution of plastic zone is investigated. The results show that the advance support of pipe shed can control the final displacement and advance displacement obviously. The reinforcement of fore-face glass fiber bolt has a certain control effect on the advance displacement, but the control effect on the final displacement is not obvious, compared with the advance support of the pipe shed, the reinforcement of the face bolt has a more obvious control effect on the extrusion deformation of the face of the palm. The advance pipe shed support can restrain the development of plastic zone of surrounding rock above the arch, but the reinforcement of the face bolt is better to restrain the development of the plastic zone of the leading core soil.
【作者单位】：中铁隧道集团有限公司;
【基金】：铁道部科技研究开发计划重大课题(2011G004)
【分类号】：U455.7

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