郑超, 吴学震, 邓涛, 等. 2022. 隧道掌子面超前锚杆连续交替式布设方案研究[J]. 工程地质学报, 30(4): 1246-1256. doi: 10.13544/j.cnki.jeg.2020-135.
    引用本文: 郑超, 吴学震, 邓涛, 等. 2022. 隧道掌子面超前锚杆连续交替式布设方案研究[J]. 工程地质学报, 30(4): 1246-1256. doi: 10.13544/j.cnki.jeg.2020-135.
    Zheng Chao, Wu Xuezhen, Deng Tao, et al. 2022. Study on continuous-alternative design scheme of advanced rock bolts on tunnel face[J]. Journal of Engineering Geology, 30(4): 1246-1256. doi: 10.13544/j.cnki.jeg.2020-135.
    Citation: Zheng Chao, Wu Xuezhen, Deng Tao, et al. 2022. Study on continuous-alternative design scheme of advanced rock bolts on tunnel face[J]. Journal of Engineering Geology, 30(4): 1246-1256. doi: 10.13544/j.cnki.jeg.2020-135.

    隧道掌子面超前锚杆连续交替式布设方案研究

    STUDY ON CONTINUOUS-ALTERNATIVE DESIGN SCHEME OF ADVANCED ROCK BOLTS ON TUNNEL FACE

    • 摘要: 在软弱围岩隧道中掌子面不稳定问题十分常见。掌子面超前锚杆作为一种重要的掌子面支护手段,目前常规采用的间断式布设方案存在锚杆的支护效果会随隧道推进过程中其支护状态的变化而忽强忽弱的问题。针对这一问题,本文提出了一种连续交替式掌子面超前锚杆布设方案。该方案将掌子面上的所有锚杆布设点位均等划分成若干个部分,在隧道推进过程中进行连续逐部分交替布设,使隧道在推进过程中锚杆支护状态更趋均匀稳定。为系统性评价新方案的可行性,以渭武高速木寨岭公路隧道为工程依托,在掌子面锚杆用量处于相同水平的条件下,分别对常规的间断式布设方案以及新提出的连续交替式布设方案进行设计。并进一步借助FLAC3D数值模拟平台,对掌子面超前锚杆采用两种不同布设方案时,对于掌子面变形以及地层变形的控制效果进行对比。结果表明,常规间断式锚杆布设方案对于掌子面变形以及地层变形的控制效果并不稳定,受支护状态变化的影响较大,而新提出的连续交替式布设方案可以在不提高支护成本的前提下,将隧道推进过程中掌子面超前锚杆对于掌子面变形以及地层变形的控制效果维持在稳定水平,且均显著高于常规方案的最低水平,克服了常规布设方案支护效果严重高低不均的缺陷。本研究为掌子面超前锚杆布设提供了一种新方法。

       

      Abstract: The instability of tunnel face is quite common in weak surrounding rock tunnels. The advanced rock bolts are effective supporting structure for the tunnel face. According to the conventional installation scheme, the advanced rock bolts have to be cut off and shortened with the excavation of tunnel, and their supporting effect can become weaker and weaker. The rock bolts can not be reinstalled until their length is cut to a predetermined value. The discontinuous installing of rock bolts leads to significant fluctuations in the supporting effect. In order to solve this problem, a continuous-alternative design scheme is proposed for advanced rock bolts on tunnel face. In the new scheme, the rock bolts on tunnel face are divided into several parts equally. The rock bolts are successively installed during the tunnel advancing process, so that the rock bolts supporting state can be more uniform and stable. In order to evaluate the feasibility of the new scheme systematically, a case analysis is carried out based on the Muzhailing Tunnel Project of the Weiwu Expressway. First, both conventional discontinuous scheme and continuous-alternative scheme are designed under the condition of the same amount of rock bolt. The finite difference software FLAC3D is used to establish numerical model. In this way, the deformations of tunnel face and ground are compared for two different design schemes. The results show that the supporting effect of rock bolts is greatly influenced by the changes of the supporting states in the conventional discontinuous installation scheme. The continuous-alternative installation scheme can contribute a stable supporting effect on tunnel face without increasing the cost. Moreover, the supporting effect is much higher than the minimum level of conventional installation scheme. This study provides a new method for the arrangement of the advanced rock bolts on tunnel face.

       

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