Research on support timing of karst tunnel based on convergence-constraint method

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Jul.2024, Vol.47 No.7: 986-994

DOI: 10.3969/j.issn.1003-5060.2024.07.020

Authors

ZHANG Juwen $ ^{1} $, LI Yongxin $ ^{2} $

(1. China Railway Tunnel Consultants Co., Ltd., Guangzhou 511458, China; 2. School of Automobile and Traffic Engineering, Hefei University of Technology, Hefei 230009, China)

Abstract and Keywords

Abstract: Caves have a significant impact on the stability of tunnels, and timely support can ensure the construction safety of karst tunnels. Taking the Bihuashan Tunnel as an example, a numerical simulation method is used to establish an analysis model of the karst tunnel. The relative position and size of the cave are the main influencing factors, including the net distance and circumferential position between the cave and the tunnel, as well as the diameter of the cave, and their effects on the displacement of the surrounding rock of the tunnel are analyzed. Through the displacement of the surrounding rock and the zone state index $ Z_{SI} $, combined with the convergence-constraint method, the timing of the support of the karst tunnel is comprehensively judged. The results show that the circumferential position of the cave has a greater influence on the stability of the tunnel compared to the net distance and diameter of the cave. Due to the influence of the cave, the displacement development law at different positions of the surrounding rock is not the same, so it is difficult to judge whether the tunnel has entered an elastic-plastic state based on a certain displacement characteristic. However, the $ Z_{SI} $ can more intuitively display the status of the karst tunnel, providing assistance in determining the timing of the support of the karst tunnel.

Keywords: karst tunnel; convergence-constraint method; zone state index; support timing; FLAC3D software

作者信息

张聚文 $ ^{1} $，李永鑫 $ ^{2} $

(1. 中铁隧道勘察设计研究院有限公司，广东广州 511458；2. 合肥工业大学汽车与交通工程学院，安徽合肥 230009)

摘要和关键词

摘要: 溶洞对于隧道的稳定性有较大的影响, 而进行及时的支护施做能够保障岩溶隧道的施工安全。文章以笔花山隧道为例, 采用数值模拟方法建立岩溶隧道分析模型, 将溶洞的相对位置和大小作为主要影响因素, 包括溶洞与隧道之间的净距和环向位置、溶洞直径, 并分析其对硐室围岩位移的影响。通过硐室位移和单元状态指标 $ Z_{SI} $, 结合收敛-约束方法, 综合判断岩溶隧道支护的施做时机。结果表明, 相较于净距和溶洞直径, 溶洞环向位置对隧道稳定性影响更大。由于溶洞的影响, 硐室不同位置处的位移发展规律并不相同, 因此较难以某一种位移特征来判断隧道是否进入弹塑性状态。而 $ Z_{SI} $ 可以更直观地展现出岩溶隧道的状态, 从而为合理地确定岩溶隧道支护施做时机提供帮助。

关键词: 岩溶隧道；收敛-约束法；单元状态指标；支护时机；FLAC3D软件

Funding

国家自然科学基金资助项目(52108312); 安徽省自然科学基金资助项目(2108085QE250)和中央高校基本科研业务费专项资金资助项目(JZ2021HGTA0160)

合肥工业大学学报(自然科学版)

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