摘要
【目标】为提高不同跨径大断面小净距隧道洞口段施工的安全性与经济性,对不同的施工方案进行研究。研究不同跨径大断面小净距隧道洞口处合理的施工方案。【方法】以新疆乌尉高速公路上新光隧道为背景,通过有限元软件MIDAS GTS NX建立同跨径小净距隧道洞口段三维力学模型,研究了中隔壁法、双侧壁法和三台阶法3种施工方案下围岩稳定性。【结果】不同施工方案下地表沉降变化规律基本一致,左右洞地表沉降最大值均出现在右拱肩处,其中三台阶法对地表沉降的控制效果最差。随着开挖深度的增大,不同施工方案下右洞拱顶沉降值变化趋势大致相同,最终沉降量由大到小为三台阶法(23.12 mm)、双侧壁法(19.96 mm)、中隔壁法(17.49 mm),而且采用三台阶法施工时围岩应力释放率最快。3种开挖方法下围岩最大塑性应变由大到小为三台阶法(2.35×10^(-2))、中隔壁法(6.29×10^(-3))、双侧壁法(5.61×10^(-3)),且使用三台阶法时塑性区发生贯通。【结论】中隔壁法和双侧壁法均能较好地控制围岩稳定性,但双侧壁法施工缓慢,综合考虑围岩稳定性、施工成本、安全和工期等因素,最终选取中隔壁法进行施工,现场监测表明隧道拱顶日均沉降量为0.51 mm,满足要求,可为类似工程提供参考。
[Objective]The study investigated various construction schemes to improve the safety and economy of tunnel entrance construction for large-cross-section small-interval tunnels with different spans.The study investigated the reasonable tunnel entrance construction scheme for large-cross-section small-interval tunnels with different spans.[Method]Shangxinguang tunnel project for Urumqi-Yuli expressway in Xinjiang was taken as the study case.Three-dimensional mechanical model of entrance section of small-interval tunnels with same span was established with finite element software MIDAS GTS NX.The surrounding rock stability was studied with three construction schemes,i.e.,center diaphragm method,double side drift method,and three-bench method.[Result]The surface settlement variation pattern with different construction schemes is basically consistent.The maximum values of surface settlement in both left and right tunnels appear at the right arch shoulders.The three-bench method has the worst control effect on surface settlement.As the excavation depth increases,the variation trend of right tunnel vault crown settlement with different schemes are roughly the same.The final settlements are ranked from large to small as three-bench method(23.12 mm),double side drift method(19.96 mm),and center diaphragm method(17.49 mm).While the stress release rate of surrounding rock is the fastest when using three-bench method for construction.The surrounding rock maximum plastic strains with three excavation methods are ranked from large to small as three-bench method(2.35×10^(-2)),center diaphragm method(6.29×10^(-3)),and double side drift method(5.61×10^(-3)).The plastic zone penetrates when using three-bench method.[Conclusion]By using both center diaphragm method and double side drift method can effectively control the surrounding rock stability,however the construction is slow with double side drift method.Taking into account factors(e.g.,surrounding rock stability,construction cost,safety,and construction period),the center diaphragm method is ultimately selected for construction.The in-situ monitoring shows that the tunnel vault crown daily average settlement is 0.51 mm,which meets the requirements.It can provide references for similar projects.
作者
肖鹏帅
梁斌
黄光友
李文杰
XIAO Pengshuai;LIANG Bin;HUANG Guangyou;LI Wenjie(School of Civil Engineering and Architecture,Henan University of Science and Technology,Luoyang,Henan 471000,China;CCCC-SHB Forth Engineering Co.,Ltd.,Luoyang,Henan 471000,China)
出处
《公路交通科技》
北大核心
2025年第7期183-190,共8页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(U1604135)
中交第二公路工程局有限公司重点科技研发项目(RP2022011745)
河南省科技厅产学研合作项目(2015HNCXY011)。
关键词
隧道工程
方案优化
数值模拟
不同跨径小净距隧道
洞口施工
tunnel engineering
scheme optimization
numerical simulation
small-interval tunnels with different spans
tunnel entrance construction
