摘要
为了探明临海富水复杂地层中大直径盾构隧道管片上浮机制并采取相应的控制措施,以福州滨海快线地铁项目为工程依托,建立了盾构机-管片-浆液-地层多因素耦合作用数值计算模型,分析了不同浆液压力分布形式下浆液-管片相互作用模式及管片上浮机制,之后通过浆液配比室内试验和现场实际应用筛选获得了壁后浆液的最佳材料配比,并进行了壁后注浆工艺改进。结果表明:浆液压力分布形式的变化对盾尾后第1环管片的上浮位移影响最大,外部浆液压力分布形式的变化对于管片上部和下部的上浮位移差影响较大,而对两侧部位的影响较小;管片下部浆液压力分布形式的改变对于靠近盾尾的相邻两环管片环间错台影响最大,管片上部浆液压力较大时,管片结构各处的轴力和弯矩整体较小,管片上部负弯矩分布范围及下部负轴力值较小;浆液水胶比和胶砂比的增加会使得浆液的稠度、流动度和初凝时间随之增加,但是粉水比却与上述3个物理指标间存在显著的负相关特性;每立方米浆液拌制过程中加入5 kg减水剂,台车砂浆罐内拌入0.5 kg速凝剂,管片上部2个注浆孔注射入40%的浆液,中部和下部两个注浆孔分别注射入30%的浆液,同时在脱出盾尾后的管片上部开孔快速注入水玻璃,能显著降低管片上浮位移。
In order to explore the segment floating mechanism of large-diameter shield tunnel in complex strata with abundant water near the sea and take corresponding control measures,based on Fuzhou Binhai Express Metro project,a numerical calculation model is established considering the multi-factor coupling effect of shield machines,segments,slurry and strata,and the slurry-segment interaction mode and the segment floating mechanism with different slurry pressure distributions are analyzed.Then,the optimal material ratio for slurry is obtained through indoor experiments and on-site practical applications,and the grouting process for the shield machine wall is improved.The result shows that(1)the change in the distribution form of slurry pressure has the greatest impact on the floating displacement of the first segment behind the shield tail,the change in the distribution form of external slurry pressure has a significant impact on the floating displacement difference of the segment upper part among different working conditions,and also has a significant impact on the floating displacement difference of the segment lower part among different working conditions,while the impact on both sides is relatively small;(2)the change in the distribution of slurry pressure at the lower part of the segment has the greatest impact on the misalignment among adjacent segments near the shield tail,when the slurry pressure at the upper part of the segment is high,the axial force and bending moment at various parts of the segment structure are generally small,and the distribution range of negative bending moment at the upper part of the segment and the value of negative axial force at the lower part are relatively small;(3)the increase in the water cement ratio and cement sand ratio of the slurry lead to an increase in the consistency,flowability and initial setting time of the slurry,but there is a significant negative correlation between the powder water ratio and 3physical indicators mentioned above;(4)a material ratio of 200 kg cement,300 kg water,680 kg sand,380 kg fly ash and 90 kg bentonite per cubic meter of slurry is used,40%slurry is injected into the upper two grouting holes of the pipe segment,while 30%slurry is injected into the middle and lower two grouting holes respectively.At the same time,water glass is quickly injected into the upper part of the pipe segment after the shield tail is removed,which can significantly reduce the floating displacement of the pipe segment.
作者
曾红波
石州
涂金光
徐金峰
肖中林
ZENG Hong-bo;SHI Zhou;TU Jin-guang;XU Jin-feng;XIAO Zhong-lin(CCCC-SHEC First Highway Engineering Co.,Ltd.,Wuhan Hubei 430000,China;Key Laboratory of Ministry of Education for Geotechnical and Underground Engineering,Tongji University,Shanghai 200092,China;Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;China Communications Strait Construction Investment Development Co.,Ltd.,Fuzhou Fujian 350000,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第1期138-151,共14页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(52038008)。
关键词
隧道工程
变形
数值计算
盾构隧道管片上浮
控制措施
tunnel engineering
deformation
numerical calculation
shield tunnel segments floating
treatment measures
