摘要
盾构隧道覆土厚度是决定盾构隧道环间压力的重要因素。采用浅覆土接收的盾构隧道在接收端附近区间覆土较薄,环间压力较小,继而会影响隧道环缝的防水性能。通过建立并求解盾构隧道纵向受力变形的数理模型,研究了浅覆土接收条件下盾构隧道环间压力的分布规律,并探讨了浅覆土接收盾构隧道与常规接收盾构隧道环间压力分布规律的异同;在此基础上提出了增大浅覆土接收盾构隧道环间压力的构造措施及其设计方法,并以上海市某在建越江隧道为背景,探讨了其在实际工程中的应用。研究结果表明,浅覆土接收盾构隧道环间压力随管片与接收端距离的增大而增大,在浅覆土接收端最小,变厚度覆土区与常厚度覆土区分界点处环间压力达到环间压力极限值的70%;背景工程中常规接收隧道分界点处环间压力约为浅覆土接收隧道环间压力的1.21倍;在靠近接收端一定范围内的管片中可设置环间预紧力螺栓,以增大环间压力。针对背景工程,需在浅覆土接收端附近约24环管片中设置预紧力螺栓。
The overburden thickness is an important factor influencing the longitudinal stresses between the rings.The overburden thickness of shallow-covered receiving shield tunnel is small near the receiving end,which would lead to small longitudinal stresses.And so the water tightness of shield tunnel will be influenced.By establishing and solving the mathematical model,the distribution law of the longitudinal stresses is proposed.The difference between the longitudinal stresses distribution law of shallow-covered receiving tunnel and that of conventional receiving tunnel is discussed.Based on the longitudinal stresses distribution law of shallow-covered receiving tunnel,the structural measures and relevant design method which increase the longitudinal stresses are proposed.Taking a river-crossing tunnel under construction in Shanghai as the background,the practical application of the structural measures is discussed.The result shows that the longitudinal stress increases with the increase of the distance from the receiving end.At the shallow-covered receiving end the longitudinal stress is the smallest.The longitudinal pressure at the dividing point of variable overburden thickness area and constant overburden thickness area reaches about 70%of the limit value of longitudinal pressure.In the background project,the longitudinal pressure of the conventional receiving tunnel is about 1.21 times that of the shallow-covered receiving tunnel.Pre-tightened bolts can be set in the segments near the receiving end to increase the longitudinal stress.For the background project,pre-tightened bolts shall be set in about 24 ring segments near the receiving end.
作者
杨振华
YANG Zhenhua(Shanghai Urban Construction Design&Research Institute(Group)Co.,Ltd.,Shanghai 200125)
出处
《现代隧道技术》
CSCD
北大核心
2022年第5期18-26,共9页
Modern Tunnelling Technology
基金
上海市科学技术委员会科研计划项目(18DZ1205102)
上海市科学技术委员会科研计划项目(19DZ1200903).
关键词
盾构隧道
浅覆土接收
结构设计
预紧力螺栓
防水性能
Shield tunnel
Shallow-covered receiving tunnel
Structure design
Pre-tightened bolts
Water tightness of the tunnel
