摘要
多连拱隧道开挖洞室多、跨度大,施工过程中荷载转换频繁,支护结构受力特征复杂,对多连拱隧道支护结构受力开展现场测试研究具有重要意义。依托长沙观音岩不等跨四连拱隧道工程,选取典型断面对各洞室初支钢拱架、二次衬砌结构进行施工全过程应力监测,以获得复杂施工步序下支护结构受力特征。测试结果表明:观音岩隧道施工中,先行主洞较后行洞室承担的围岩压力更大,右主洞、左右辅洞开挖顺序居后,施工扰动次数较少,支护结构内力较小;各洞室中,初支钢拱架内力整体均呈“左小右大”的非对称分布特征,其最大轴向压力402.71 kN、最大弯矩7.97kN·m出现在左主洞的右拱脚处,二衬内力整体非对称程度较低,只以左主洞呈显著非对称分布,其余洞室呈整体对称分布;先行左主洞支护结构的内力扰动主要由受后行邻洞的开挖影响所产生,后行右主洞、左辅洞开挖支护阶段,左主洞初支钢拱架、二衬结构绝大部分位置其内力增量超过总增量的一半;采用“先主后辅,左主先行”施工方案,施工全过程支护结构的安全性均满足规范要求,支护结构设计和施工措施合理。研究成果可为复杂条件下多连拱隧道的设计与施工提供借鉴。
The excavation of multi-arch tunnels with large chambers and spans leads to frequent load transfers and complex stress characteristics on the support structures,and the field tests allow for a more accurate study on the stress distribution characteristics of this kind of support structures.Based on the Guanyinyan unequal span four-arch tunnel project in Changsha,the strain gauges are used to monitor the stress characteristics in typical sections during the whole construction process of the steel arches and secondary linings.The test results reveal that the main advance tunnel experiences greater pressure of the surrounding rock compared with the subsequent tunnels.The excavation of the right main tunnel and the left and right auxiliary tunnels occurs later,resulting in fewer disturbances and smaller internal forces of the support structures.The overall distribution of internal forces of the steel arches is asymmetrical,with higher forces at the right side.The maximum axial pressure of 402.71 kN and the maximum bending moment of 7.97 kN·m are observed at the right foot of the left main tunnel.The secondary linings exhibit low asymmetry,only with the left main tunnel showing significant asymmetrical distribution.The internal force disturbances in the support structures of the left main tunnel are primarily influenced by the excavation of the subsequent adjacent tunnels.During the excavation and support stages of the subsequent right main tunnel and left auxiliary tunnel,most positions in the left main tunnel experiences the internal force increment exceeding half of the total increment.In summary,the construction plan of“first main and then auxiliary,left main first”is found to be reasonable,and the support structures meet the specification requirements.The research findings can provide references for the design and construction of multi-arch tunnels under complex conditions.
作者
阳军生
汤冲
柏署
谢亦朋
李雨哲
杨磊
YANG Junsheng;TANG Chong;BAI Shu;XIE Yipeng;LI Yuzhe;YANG Lei(School of Civil Engineering,Central South University,Changsha 410075,China;Hunan Provincial Communications Planning,Survey and Design Institute Co.,Ltd.,Changsha 410200,China;China Railway 25th Bureau Group Co.,Ltd.,Guangzhou 542814,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2024年第10期2030-2040,共11页
Chinese Journal of Geotechnical Engineering
基金
湖南省交通运输厅科技项目(201915)。
关键词
四连拱隧道
支护结构
现场测试
受力特征
安全性评价
four-arch tunnel
support structure
field test
stress characteristic
safety evaluation
