大直径盾构隧道施工对城市主干道路面沉降影响分析

京张高铁清华园隧道采用盾构法施工(外径为12.2 m),隧道连续穿越北京市区成府路、北四环路、知春路、北三环路及学院南路5条重要市政道路。采用数值计算及现场监测方法,依据下穿不同道路的盾构实际掘进参数分析各工序对道路沉降的影响。根据Peck公式计算沉降值并与实测路面沉降值进行对比分析,得到适用于穿越不同地层的K值。结果表明,隧道浅埋穿越道路的沉降值较小且后期注浆补偿效果好;北京地区砂卵石地层K值宜为0.3,黏性土地层K值宜为0.46~0.65。

Analysis of the Influence of Large Diameter Shield Tunneling on Pavement Settlement of Major Urban Roadways

TSinghuayuan Tunnel of Beijing-Zhangjiakou High-speed Railway is constructed by shield method.This tunnel has an outer diameter of 12.2 m.Tsinghuayuan Tunnel crosses five major municipal roads including Chengfu Road,North 4 th Ring Road,Zhichun Road,North 3 rd Ring Road and Xueyuan South Road.The article focuses on parameter design of shield tunneling,and analyses the influence of each procedure on pavement settlement with simulation method and field monitoring method.Also the measurement results are compared with calculated value by Peck Formula,the figures of K for different strata are obtained.The results show that the settlement is little when the tunnel undercrossing road with shallow covering,and also the compensation grouting effect behind shield tunnel segments later in this case is better.In this paper,basing on the practical requirements,the value of K in sand gravel layer should be 0.3,while in clay soil layer it should be 0.46~0.65.Thus,the study in this paper can provide guidance for the shield tunnel’s underpass project.