以色列特拉维夫地铁红线先隧后站施工技术应用

特拉维夫地铁红线西段原施工方案为车站与盾构掘进平行穿插施工,盾构始发井已经完成,但车站还没有进场施工,个别车站场地存在移交滞后风险,并且大部分车站基坑设计采用水下开挖、封底和长锚索抗浮方案,施工难度大、工艺复杂、工期长,会导致盾构掘进不连续,造成窝工。新的承包商中标后,为解决中间车站和盾构之间的交叉施工问题,降低工期滞后和工程费用超支风险,通过充分的评估、分析和论证,将部分关键区段优化为“先隧后站”施工,并将车站基坑开挖和封底方案优化为降水干式开挖、封底方案,以及采取设置墙体锚固销棒或抗拔桩抗浮等措施。优化后的方案在实施过程中很大程度上减少了车站和盾构施工的相互干扰,规避了大量车站端头软弱富水地层盾构到达接收和二次始发等高风险施工工序,降低了工程技术难度和施工风险,提高了工程质量(特别是接口处的防水和实体质量),最终使整个土建工程得以提前交付,保证了总体工期目标,综合成本也得到了有效控制。

Application of Construction Technology of "Tunneling First and Then Station"in Tel Aviv Red Line Project in Israel

The original construction plan for the western section of the Red Line of Tel Aviv Metro in Israel is theparallel construction of the station and shield tunneling. The shield launching shaft has been completed, but the stationhas not been begun. The risk of handover delay exists in some station sites, and most of the foundation pits of the stationare designed with the underwater excavation, bottom sealing and the anti-floating scheme of long anchor cable. Theconstruction difficulty is large, the technology is complex, and the construction period is long, which will cause theshield tunneling discontinuity and the sluggish work. In order to realize the cross construction between the intermediatestation and the shield construction, and reduce the risk of project delay and overexpenditure, after adequate evaluation,analysis and demonstration, the construction scheme of some key sections is optimized as " tunneling first and thenstation", and the foundation pit excavation and bottom sealing schemes of the station are optimized as dewatering dryexcavation and bottom sealing scheme, as well as the wall anchoring pin bars or pulling pile anti-floating is adopted. Theoptimized solutions largely reduce the interference between station and shield construction, avoid a large number of highriskconstruction processes such as the shield arrival and secondary launching in weak and water-rich stratum at the endof the station, reduce the engineering technical difficulty and construction risk, improve the engineering quality(especially the waterproofing and solid quality of joints), guarantee the construction period, and effectively control thecomprehensive cost.