摘要
为应对高地应力软岩隧道挤压大变形问题,开展双层初期支护的支护时机与厚度比研究,以期得到最优化双层初期支护施工方案。首先对大亮山隧道单层初期支护出现的变形侵限、喷射混凝土开裂和钢拱架扭曲等灾害进行描述分析,再针对双层支护方案,利用数值模拟方法对双层初期支护的不同支护时机与厚度比进行对比分析。结果表明:适当降低第1层初期支护厚度与增大第2层初期支护滞后进尺可以充分释放围岩的变形压力;当第1层初期支护厚度较小时,第2层初期支护滞后进尺为控制围岩变形收敛的主要因素,第2层初期支护滞后时间较长时,双层初期支护结构厚度比为控制围岩变形收敛的主要因素;采用双层初期支护厚度比为1.0,第2层初期支护滞后2个开挖进尺的支护方案既可以释放围岩压力,也能有效控制变形收敛,保障隧道安全掘进。
The support timing and thickness ratio of double-layer primary support are studied to deal with the large deformation of soft rock tunnels with high ground stress and obtain the optimal construction scheme of double-layer primary support.Firstly,disasters such as deformation intrusion,shotcrete cracking and steel arch distortion in the single-layer initial support of Daliangshan Tunnel were described and analyzed.Then,the numerical method was used to compare and analyze different support timing and thickness ratios of the double-layer initial support.The results show that the deformation pressure of the surrounding rock can be fully released by appropriately reducing the thickness of the initial support of the first layer and increasing the lag footage of the initial support of the second layer.When the thickness of the initial support of the first layer is small,the lag footage of the initial support of the second layer is the main factor to control the convergence of surrounding rock deformation.When the lag time of the initial support of the second layer is long,the thickness ratio of the initial support structure of the double-layer is the main factor to control the convergence of surrounding rock deformation.The support scheme with the double-layer initial support thickness ratio of 1.0 and the second layer initial support lagging two excavation footages can not only release the surrounding rock pressure but also effectively control the deformation convergence and ensure the safe excavation of the tunnel.
作者
袁刚
徐金峰
李守仁
谢雄耀
严绍明
王安民
YUAN Gang;XU Jinfeng;LI Shouren;XIE Xiongyao;YAN Shaoming;WANG Anmin(Yunnan Linyun Expressway Co.,Ltd.,Lincang,Yunnan675800,China;Department of Geotechnical Engineering,Tongji University,Shanghai200092,China;Broadvision Engineering Consultants,Kunming,Yunnan650041,China)
出处
《施工技术（中英文）》
CAS
2023年第19期58-65,95,共9页
Construction Technology
基金
国家自然科学基金重点项目(52038008)
云南省交通运输厅科技项目(云交科教便〔2021〕7号)。
关键词
隧道
地应力
软岩
变形
初期支护
数值模拟
厚度比
tunnels
ground stress
soft rock
deformation
primary support
numerical simulation
thickness ratio
