山岭铁路盾构隧道荷载及结构受力特性研究
Study on Load and Structural Force Characteristics of Shield Tunneling in Mountainous Railway
符亚鹏 1豆留盼 2靳宝成 1王新东 1方勇2
作者信息
- 1. 中铁第一勘察设计院集团有限公司,西安 710043
- 2. 西南交通大学,成都6100
- 折叠
摘要
研究目的:为研究山岭盾构隧道的荷载分布特征及其衬砌结构力学行为,依托某铁路工程,基于FLAC3D建立数值模型,研究山岭铁路大断面盾构隧道管片上的荷载分布及大小,分析不同影响因素下双层衬砌的内力分布特征.研究结论:(1)衬砌周边围岩应力在盾构通过前后,有瞬间增大再减小再增大最后保持不变的趋势,且稳定后衬砌上竖向和侧向地层压力均呈两端大中间小形状分布;(2)隧道在不同赋存条件下应选用与其相适应的荷载计算理论,如在50m埋深(Ⅴ级围岩)条件下宜采用普氏理论,100m埋深(Ⅴ级围岩)条件下宜采用铁路隧道规范理论;当围岩条件较差及埋深较浅时荷载计算理论结果略微偏于不安全,当埋深较大以及围岩条件较好时荷载计算理论结果均偏保守;(3)双层衬砌结构中二次衬砌相比管片内力很小,且围岩稳定性对二次衬砌的受力特性影响较大;(4)本研究成果可为山岭盾构隧道结构设计提供技术支撑.
Abstract
Research purposes:In order to investigate the load distribution characteristics of mountainous shield tunnel and the mechanical behavior of its lining structure,this paper focuses on a specific railway project.Utilizing the finite difference software FLAC3D,a three-dimensional numerical model is established to study the load distribution and magnitude on the segment of the shield tunnel in a large-section mountainous railway tunnel.The paper also analyzes the internal force distribution characteristics of single and double-layer linings under various influencing factors.Research conclusions:(1)The stress in the surrounding rock of the lining exhibits a trend of instant increase,decrease,subsequent increase,and eventual stabilization before and after the shield tunnel passes through.After stabilization,both the vertical and lateral earth pressures on the lining show a distribution pattern with higher values at the ends and lower values in the middle.(2)The tunnel should employ load calculation theories that correspond to its existing conditions.For instance,the Prandtl theory is suitable for a 50 m depth(Class Ⅴ surrounding rock),while the railway tunnel code theory is suitable for a 100 m depth(Class Ⅴ surrounding rock).When the surrounding rock conditions are poorer and the depth is shallower,the results of load calculation theories slightly lean towards being less safe.On the other hand,for greater depths and better surrounding rock conditions,the results of load calculation theories tend to be conservative.(3)In a double-layer lining structure,the secondary lining experiences minimal internal forces compared to the segments.Furthermore,the stability of the surrounding rock significantly affects the stress characteristics of the secondary lining.(4)This research outcome can provide technical support for the structural design of mountainous shield tunneling.
关键词
铁路盾构隧道/荷载分布/结构受力/数值模拟Key words
railway shield tunnel/load distribution/structural stress/numerical simulation引用本文复制引用
基金项目
中国铁建股份有限公司科研项目(18-C39)
中铁第一勘察设计院集团有限公司科技研发计划(院科19-73)
出版年
2024
NETL
NSTL
万方数据