摘要
为研究大跨公路隧道施工期二次衬砌力学行为的演变特征,依托实际工程展开现场监测和数值计算。通过对比分析揭示了施工期隧道二衬内力和衬砌接触压力的分布情况和演化特征,并以此评估现场二衬的荷载分摊比和衬砌施作时机,为公路隧道二衬设计提供参考。结果表明:数值模拟与现场测试结果吻合较好,二次衬砌的荷载分摊比约为0.4,表明现场二衬的施作时机合理;二衬浇注后,水化反应引起的结构体积膨胀对二衬力学行为的影响较大,水化反应的影响在3 d内达到峰值,影响时间约为二衬浇注后的2~3周;现场测试表明,水化反应结束后,二衬拱顶、拱肩和拱脚处的接触压力基本趋于稳定,各部位的接触压力分别在0~20,70~80,5~10 kPa范围,而拱脚接触压力随施工进度呈先减后增的发展趋势,并最终稳定于200 kPa左右;二衬内力随着施工进度不断增长,施工完毕时,二衬拱顶、拱墙、拱腰处的轴向压力分别为450,140,200 kN,各部位的弯矩量值较小,结构安全冗余度充足;数值计算的结果表明,当二衬浇注断面在研究断面15 m以内时,拱脚接触压力的增长速度较快,当二衬浇注断面超过研究断面45 m后,衬砌接触压力和二衬内力趋于稳定。
In order to study the evolution characteristics of mechanical behaviour for secondary lining of largespan tunnel during construction,the field test and numerical calculation are applied based upon realistic project.The distribution state and development rule of secondary lining’s internal force and contact pressure are obtained through comparison,and the load bearing ratio and construction timing of secondary lining can be evaluated accordingly to provide reference for the design of highway tunnel secondary lining.The result shows that the numerical calculation result is similar to the field test,and the bearing ratio of secondary lining is close to 0.4.After the secondary lining is cast,the volumetric expansion of the structure induced by hydration reaction has a significant effect on its mechanical behavior,and the influence of hydration reaction reaches its peak within 3 d and lasts for 2-3 weeks.According to the field test,the contact pressure on tunnel vault,side walls and tunnel invert tend to stabilize within the range of 0-20,70-80 and 5-10 kPa respectively after the hydration reaction,while the contact pressure on arch foot shows a trend of first decreasing and then increasing as the construction progresses,which finally reaches a level around 200 kPa.The internal force of secondary lining grows continuously as the construction progresses;the axial compression force on tunnel vault,side walls and tunnel invert are 450,140 and 200 kN respectively.The bending moment is relatively minor on each part of the structure,therefore,the secondary lining has sufficient safety redundancy.According to the numerical calculation,the growth rate of contact pressure on arch foot is relevantly faster when the casting section of the second lining is within 15 m from the research section.When the casting section of the second lining passes research section by over 45 m,the contact pressure between linings and the internal force of the second lining tend to stabilize.
作者
胡学亮
南骁聪
张文亮
朱德保
HU Xue-liang;NAN Xiao-cong;ZHANG Wen-liang;ZHU De-bao(Shandong Hi-speed Group Co.,Ltd.,Jinan,Shandong 250101,China;Shandong Hi-Speed Engineering Test Co.,Ltd.,Jinan,Shandong 250002,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第3期151-162,共12页
Journal of Highway and Transportation Research and Development
关键词
隧道工程
衬砌力学行为
现场监测
二次衬砌
大跨度隧道
施工期
tunnel engineering
mechanical behavior of lining
field test
secondary lining
large-span tunnel
construction period
