基于地铁隧道轮廓线内的桩基处理方案对比分析

Comparative Analysis of Pile Foundation Treatment Schemes in Metro Tunnel Contour

成都轨道交通17号线二期项目起于机投桥站,止于高洪站,线路总长24.76 km,均为地下线,共设地下站18座,设计速度140 km/h,共投入22台8.6 m大直径盾构机施工。其中踏水桥站—二仙桥站区间隧道下穿既有7号线二仙桥站主体结构,区间隧道拱顶距既有7号线结构底板净距仅1.5 m,同时7号线的施工的围护结构和临时立柱桩侵入17号线二期隧道线界,并面临超近距离侧穿市政匝道桥桩和上覆复杂管线及老旧建筑物等复杂条件制约,因此需要提前采取措施。论文以拔桩、暗挖、顶管取芯、盾构切桩等几种工法为例,从安全风险、难易程度、时间周期、经济性等几方面进行了综合论述,同时阐述了各种工法的利弊风险,为以后类似项目提供借鉴经验。

The second phase project of Chengdu Rail Transit Line 17 starts at Jitouqiao station and ends at Gaohong station.The total length of the line is 24.76 km.There are 18 underground stations with a design speed of 140 km/h.Among them,the interval tunnel between Taishuiqiao station and Erxianqiao station undercuts the main structure of Erxianqiao station of line 7,and the distance between the arch crown of the interval tunnel and the bottom plate of the structure of line 7 is only 1.5 m,at the same time,the surrounding structure and temporary column piles of the construction of line 7 encroach into the boundary of the second-phase tunnel of line 17,and face the complicated conditions such as crossing municipal ramp bridge piles and overlying complicated pipelines and old buildings at super close range,therefore,measures need to be taken in advance.Taking several construction methods,such as pulling out piles,digging under the ground,pushing the pipe to take core,cutting piles by shield machine,as examples,this paper gives a comprehensive discussion on safety risk,difficulty degree,time cycle,economy,etc.,provide reference experience for similar projects in the future.