城市浅埋岩溶地层溶腔位置对地铁隧道施工力学影响的模型试验
周安琦1王士民1陈发达2王祥2陈兵1
Model Experiment for Mechanical Impact of Karst Cave Location on Metro Tunnel Construction in Urban Shallow-buried Karst Strata
ZHOU Anqi1WANG Shimin1CHEN Fada2WANG Xiang2CHEN Bing1
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作者信息:1.西南交通大学交通隧道工程教育部重点实验室， 610031， 成都
2.贵阳市公共交通投资运营集团有限公司， 550081， 贵阳
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Affiliation:1.Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University, 610031, Chengdu, China
2.Guiyang Public Transport Investment and Operation Group Co., Ltd., 550081, Guiyang, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.20245704
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中图分类号/CLCN:U455.43;U231.3
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栏目/Col:土建工程
摘要:
［目的］在城市浅埋岩溶环境下修建地铁隧道，探明不同位置的隐伏溶洞，对岩溶地层的扰动影响及地面响应规律具有重要意义，需要对此进行分析研究。［方法］以贵阳地铁3号线典型岩溶隧道为依托，对岩溶区隧道施工模型进行了设计，并建立了相应的量测系统。选取了无溶腔（工况1）、溶腔发育于隧道拱顶（工况2）、溶腔发育于左拱腰（工况3）、溶腔发育于拱底（工况4）4个工况。设计了12个开挖步，对洞周围岩土压力释放情况、隧道拱架轴力和弯矩、地面沉降进行了分析，并将监测数据通过相似比换算成工程原型结果。［结果及结论］隐伏溶腔的存在，使得溶腔洞周一定范围内围岩有应力释放。工况2、工况3、工况4下围岩土压力的最终释放值分别为工况1的53.8%、42.0%、67.6%。工况3下初期支护的轴力、弯矩分别为工况1的132.9%、175.6%，属最不利工况。工况2、工况3、工况4下拱顶处地面沉降的最终值分别为32.8 mm、17.2 mm、23.0 mm，分别为工况1的172.6%、90.5%、121.1%。工况2下地面沉降量及沉降范围显著增加。
Abstracts:
［Objective］ In the construction of metro tunnels in urban shallow-buried karst environments, it is of great significance to investigate the location of concealed karst caves and their effects on the disturbance of karst strata and the land surface response, which requires thorough analysis and research. ［Method］ Based on a typical karst tunnel of Guiyang Metro Line 3, a tunnel construction model in karst areas is designed, and a corresponding measurement system is established. Four conditions are selected: no karst cavity (condition 1), karst cavity developed at tunnel vault (condition 2), karst cavity developed at the left arch waist (condition 3), and karst cavity developed at the arch invert (condition 4). 12 excavation steps are designed, and the release of surrounding rock pressure, tunnel arch axial force and bending moment, and land subsidence are analyzed. The monitoring data are converted into engineering prototype results based on similarity ratios. ［Result & Conclusion］ The presence of concealed karst cavities leads to surrounding rock stress release within a certain range around the cavity. The final release values of surrounding rock pressure for conditions 2, 3, and 4 are 53.8%, 42.0%, and 67.6% of that in condition 1 respectively. The axial force and bending moment of the initial support under condition 3 are 132.9% and 175.6% of those in condition 1, making it the most unfavorable condition. The final land subsidence values at arch vault for conditions 2, 3, and 4 are 32.8 mm, 17.2 mm, and 23.0 mm, respectively, which are 172.6%, 90.5%, and 121.1% of the value in condition 1. The land subsidence amount and range have significantly increased under condition 2.
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