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高地应力软岩隧道仰拱结构受力特性与参数优化

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为探索高地应力软岩隧道施工期间仰拱结构受力特性与合理支护参数,以陕西省宝汉高速公路连城山隧道工程为依托,针对仰拱施工病害及其主要影响因子,采用现场试验与数值模拟相结合的方法,探讨了不同影响因素下的仰拱结构变形与力学响应,分析了仰拱结构变形与受力对不同影响因素的敏感性,基于仰拱结构病害特征及数值模拟结果,对仰拱半径(深度)、仰拱厚度等支护参数进行了优化,并进行了工程验证.结果表明:连城山隧道施工期间仰拱二次衬砌最大接触压力达 1.034 MPa,混凝土最大应力超过其抗压强度(30 MPa),出现了仰拱回填隆起、开裂等病害,仰拱设计支护参数难以保障结构稳定;地应力水平和基底围岩劣化对仰拱结构变形与受力状态均有显著影响,其中基底软化深度的影响最为突出,地应力水平次之;减小仰拱半径、增大仰拱厚度、增大仰拱钢筋直径、减小仰拱钢筋间距均能显著抑制仰拱变形,而提高混凝土强度等级对控制仰拱变形效果不明显,且经济性较差;优化后的仰拱受力得以明显改善,有效控制了仰拱结构病害,避免了频繁拆换仰拱,保障了隧道结构安全稳定.研究成果可为类似软岩隧道仰拱变形控制及病害防治提供重要借鉴.
Mechanical Property and Parameter Optimization of Inverted Arch Structure in Soft Rock Tunnel under High Geo-stress
In order to explore the mechanical properties and reasonable support parameters of the inverted arch during the construction of soft rock tunnels under high geo-stress,field tests and numerical simulations are conducted based on the Lianchengshan Tunnel of Baoji-Hanzhong Expressway in Shaanxi Province.Aiming at the construction diseases and main influencing factors of inverted arches,the structural deformation and mechanical response of the inverted arch are investigated by different influencing factors,and the sensitivity of the deformation and stress of the inverted arch on different influencing factors is analyzed.Based on the disease characteristics and numerical simulation results of the inverted arch,the support parameters such as the radius(depth)and thickness of the inverted arch are optimized and verified in engineering.The result shows that(1)During the construction of the Lianchengshan Tunnel,the maximum contact pressure of the secondary lining at the inverted arch reaches 1.034 MPa,and the maximum stress of the concrete exceeds its compressive strength(30 MPa),resulting in diseases such as floor heave and cracking of the inverted arch backfill.The design support parameters of the inverted arch are difficult to ensure structural stability.(2)The level of ground stress and the deterioration of the surrounding rock of the foundation have a significant impact on the structural deformation and stress state of the inverted arch,with the influence of the softening depth of the foundation being the most prominent,followed by the level of ground stress.(3)Reducing the radius of the inverted arch,increasing the thickness of the inverted arch,increasing the diameter of the inverted arch steel bars,and reducing the spacing between the inverted arch steel bars can significantly suppress the deformation of the inverted arch.Increasing the strength grade of concrete,however,has no significant effect on controlling the deformation of the inverted arch,and its economic efficiency is poor.(4)The optimized inverted arch significantly improves its own stress performance,effectively controlling the structural defects of the inverted arch,avoiding frequent dismantling and reinstallation,and ensuring the safety and stability of the tunnel structure.The research results can provide important reference for the deformation control and disease prevention of the inverted arches of similar soft rock tunnels.

tunnel engineeringmechanical propertyfield testparameter optimizationinverted archsoft rock

陈建勋、牛嘉伟、刘伟伟、罗彦斌、陈丽俊

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长安大学 公路学院, 陕西 西安 710064

隧道工程 受力特性 现场试验 参数优化 仰拱 软岩

国家自然科学基金项目国家自然科学基金项目陕西省交通运输厅科技项目陕西省自然科学基础研究计划项目长安大学中央高校基本科研业务费专项资金项目

418312865230839019-06k2023-JC-QN-0383300102213103

2024

10.3969/j.issn.1002-0268.2024.01.015

公路交通科技
交通运输部公路科学研究院

公路交通科技

CSTPCD北大核心
影响因子：1.007
ISSN：1002-0268
年,卷(期)：2024.41(1)
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