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ORIGINAL RESEARCH article

Front. Earth Sci.
Sec. Petrology
Volume 12 - 2024 | doi: 10.3389/feart.2024.1469344

Influence of variation of construction parameters on stability of surrounding rock of soft rock tunnel

Provisionally accepted
Junhong Li Junhong Li 1Hongpan Shao Hongpan Shao 2Yu Xiong Yu Xiong 2Yuxue Chen Yuxue Chen 3*Qiqiang Nie Qiqiang Nie 2
  • 1 China Railway Development and Investment Group Co., Ltd, Kunming, China
  • 2 China Railway Tenth Bureau Group Third Construction Co., Ltd, Hefei, China
  • 3 Shandong University, Jinan, China

The final, formatted version of the article will be published soon.

    The stability of surrounding rock is an important engineering challenge for soft rock tunnels. Based on Flac3D finite difference numerical simulation software, this paper analyzes the typical area of Fenghuang Mountain tunnel in Chuxiong section of central Yunnan water diversion.Three construction methods, reserved core soil method and CD method are carried out, and two excavation parameters are different length of upper step and height of lower step. The whole excavation process of red layer soft rock tunnel is simulated under four supporting conditions: different bolt length, different bolt spacing, different initial support thickness and advance grouting strength. The results show that the CD method has a strong constraint on the vertical displacement of surrounding rock at the arch, the reserving core soil method has a better effect on controlling the uplift value, and the three-step method has a better constraint on the horizontal convergence of surrounding rock at the arch waist. The increase of the distance between the upper and lower steps has a great influence on the horizontal convergence value of the tunnel, and the lower steps have a better inhibition effect on the horizontal convergence value of the surrounding rock at the tunnel arch. The increase of lining thickness has a significant effect on restraining the deformation of surrounding rock, and the advance grouting to enhance the mechanical parameters of surrounding rock is a very efficient way to reduce the displacement of surrounding rock. The support optimization engineering application is carried out in the 6# construction branch tunnel of Fenghuang Mountain Tunnel, and good results are obtained.

    Keywords: Keyword：Middle red layer of Yunnan, Diversion tunnel, Surrounding rock stability, Variation of construction parameters, soft rock

    Received: 23 Jul 2024; Accepted: 28 Oct 2024.

    Copyright: © 2024 Li, Shao, Xiong, Chen and Nie. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Yuxue Chen, Shandong University, Jinan, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.