超大直径泥水平衡盾构推拼同步技术工程实践

Case Study on"Shield Boring+Segment Erection"Synchronization Technology in Tunneling by Super-Large Diameter Slurry Balanced Shield

为有效解决传统推进与拼装步进式施工工艺应用于长距离盾构区间造成的施工周期过长问题,提出一种基于推力矢量主动控制技术的盾构推拼同步工法,给出在已有缺失推力自补偿计算方法基础上的优化方案,将该技术搭载于14 m级超大直径泥水平衡盾构,并成功应用于上海市域铁路机场联络线工程。对第1022环的推拼同步系统响应数据进行分析,得出以下结论:1)推进油缸压力执行精度为±5%,存在短时响应延迟的现象;2)总推力在油缸回缩和顶回瞬间分别出现骤降后快速回升和骤升后快速回落的情况,整体控制在设定目标值的±3%;3)盾构推进速度受总推力影响显著,与总推力协同变化;4)盾构受外周土体包裹,总推力矢量的微小变动对盾构姿态不产生明显影响。对单月推拼同步施工351环数据进行分析后发现,采用盾构推拼同步技术相较于传统作业方式施工工效可提升约27%。

In order to solve the problem of long construction period of long shield-bored tunnels where the segment erection is started after the shield boring is finished,the authors propose the"shield boring+segment erection"synchronization technology based on the active control of the thrust vector,and provide an optimization scheme based on the self-compensation calculation method for the missing thrust.Such technology is used on a super-large diameter(∅14.07 m)slurry balanced shield,which is successfully applied in the Airport Link Line of Shanghai Suburban Railway.The system response data of the shield during the erection of segment ring No.1022 are analyzed and conclusions drawn are as follows:(1)The execution accuracy of the pressure of the propulsion cylinders is±5%,with the phenomenon of short-term response delay.(2)At the moment when the cylinders retract,the total thrust drops sharply before it rises;at the moment when the cylinders extend,the total thrust rises sharply before it drops;the error of the total thrust is controlled within±3%of the set target value.(3)The shield boring speed is significantly affected by the total thrust,and shares the same trend with the total thrust.(4)The small changes of the thrust vector do not have significant impact on the shield posture,since the shield is surrounded by the soil mass.The construction data of 351 segment rings accomplished in one month by using the"shield boring+segment erection"synchronization technology is analyzed,and the result shows that the adoption of the"shield boring+segment erection"synchronization technology improves the tunneling efficiency by about 27%,compared with the conventional"segment erection after shield boring"technology.