浅埋单护盾TBM隧道施工地表变形规律研究

Research on the Surface Deformation of Single-shield TBM Construction in Shallow Buried Environment

重庆轨道交通环线重庆西站-上桥站区间使用单护盾TBM进行施工,通过浅埋段时,因隧道拱顶穿越的基岩最小厚度已不足0.5 m,极可能会给工程带来极大安全隐患。按设计要求,对上覆土体进行旋喷桩加固与钻孔注浆加固。利用有限元数值软件ADINA建立该区段的精细有限元模型,并提出了适用单护盾TBM施工特点的数值模拟方法。数值计算结果不仅说明了表层土的加固是有效的且十分必要,并对单护盾TBM掘进过程的三个主要施工参数研究与对比分析,总结出工程浅埋段"最优掘进参数"。对比现场地表位移监测数据,总结得出该浅埋区间单护盾TBM隧道施工地表横向变形曲线"高低肩"的特点;另一方面也验证了数值模型的可用性与模拟方法的正确性,可为该区域其它地铁线路的施工提供借鉴与参考。

The running tunnel between the Chongqing West Station and Shangqiao Station in Chongqing transit circle line was excavated by a single-shield TBM. It may bring a huge potential hidden danger during the shallow-buried section as the buried depth is less than 0.5 m. The upper soil should be reinforced by chemical churning pile and bored grouting according to the requirement of project design. A three-dimension finite element model was established by ADINA using a numerical method applying to TBM construction. The numerical results show that soil reinforcing is effective and necessary,and 'the optimal tunneling parameters'were obtained by comparing the site construction parameters. It comes to the conclusion that the TSP( transverse settlement profile) curve has the characteristics of 'unbalanced groove width'by comparing to the surface monitoring data. Finally,the availability of numerical model is verified,and satisfactory agreements indicate the correctness of the simulation method. The research has potential applications to fundamentally guide the follow-up construction of the tunnel using TBM.