无水砂黏复合地层盾构掘进地表沉降规律及公式适用性研究  

Laws of Surface Settlement Caused by Shield Construction in Waterless Sand-clay Composite Stratum and Applicability of Formula

作　　者：尹鸿威 安建永[2] 金昕 雷海波 管晓明[1] 于云龙[1] Yin Hongwei;An Jianyong;Jin Xin;Lei Haibo;Guan Xiaoming;Yu Yunlong(School of Civil Engineering,Qingdao University of Technology,Qingdao 266033,China;China Construction Second Engineering Bureau LTD,Beijing 100160,China)

机构地区：[1]青岛理工大学土木工程学院,山东青岛266033 [2]中国建筑第二工程局有限公司,北京100160

出　　处：《市政技术》2021年第11期70-79,共10页Journal of Municipal Technology

基　　金：国家自然科学基金项目(51708317);山东省重点研发计划(公益类)项目(2019GSF111027);中建二局科研项目(91110000100024296D170006)。

摘　　要：依托某地铁区间的无水砂黏复合地层盾构隧道工程,通过分析实际监测数据,研究了盾构掘进过程引起的横向沉降槽成槽规律;通过分析隧道轴线上方纵向地表沉降曲线,提出了盾构施工纵向沉降的模式,并分析了沉降机理;探讨了常用盾构隧道地表沉降预测公式的适用性问题。研究结果表明:盾构机到达监测断面后,沉降槽开始出现;当盾构机盾壳完全穿越监测断面后,随着管片从盾尾脱出,沉降快速发展,从刀盘通过监测断面8.4 m到刀盘通过监测断面16.8 m,该阶段沉降通常占总沉降的50%;当刀盘通过监测断面33.6 m时,沉降槽已经基本稳定;盾构隧道施工引起的纵向地表沉降曲线分为缓降型和陡降型沉降模式,缓变型沉降模式主要在于盾构隧道正上方存在较厚的粉质黏土,对变形的传导起到减缓作用,陡降型沉降模式的发生主要与砂土层受扰动变形大、掘进参数和注浆材料设置不合理等原因有关;通过比较计算值与实测值的残差平方和,发现Attewell公式更适用于盾构穿越该砂黏复合地层的地表沉降预测。Based on analyzing actual monitoring data of a waterless sand-clay composite formation shield tunnel project in a metro section,the formation law of the traverse settlement grooves during the process of shield excavation was investigated.By analyzing the time-history curves of the vertical ground settlement above the tunnel axis,the longitudinal settlement mode of shield construction was proposed and the settlement mechanism was analyzed.The applicability of the commonly used prediction formulas for surface settlement of shield tunnels was discussed.The research results show that the settlement grooves began to appear after the shield machine had reached the monitoring section.When the shield shell of the shield machine completely passed through the monitoring section,the settlement developed rapidly with the segment broking out from the shield tail.During the period from the cutterhead passed through 8.4 m of the monitoring section to 16.8 m,the settlement usually accounted for 50%of the total settlement.When the cutterhead passed through 33.6 m of the monitoring section,the settlement groove had basically been stable.The longitudinal time-history settlement curve caused by the process of shield excavation can be divided into slowly down and steep drop-down settlement modes.The slow-down settlement mode was mainly due to the existence of thick silty clay directly above the shield tunnel,which slowed down the transmission of deformation.The occurrence of the steep drop-down settlement mode was mainly because of the sand stratum deformation greatly after being disturbed,the boring parameters ande unreasonable setting of grouting materials.Compared sum of the squared residuals of the calculated value and the measured value,Attewell formula was found to be the most suitable for the prediction of surface settlement of the shield through the sand-clay composite formation.

关 键 词：盾构隧道施工 砂黏复合地层 沉降槽 纵向沉降模式 公式适用性 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]