地铁大跨无柱车站中抗拔桩选型研究

Study on selection of uplifting force resistance piles in long-span subway station without columns

地铁无柱车站相比有柱车站具有更好的建筑功能和运营效率,但由于其自身结构特点,在高水位下无柱车站底板受力过大,通常在底板中部设置大直径抗拔桩作为受力支点以减小板厚,但当车站埋深较深且位于岩层中时,车站成本造价增高、施工难度加大。针对此问题,结合徐州某大跨无柱车站实际设计案例,提出采用微型抗拔桩方案解决无柱车站底板受力问题,并从经济性、适用性等多角度同常规大直径抗拔桩方案进行比选,比选结果表明,微型抗拔桩方案可降低抗拔桩成本造价、减小施工难度、缩短工期,减小了无柱车站在高水位下的应用难度。

Subway columnless station has better building function and operation efficiency than the station with column,but because of its own structural characteristics,the uplifting force on the bottom plate of the station without column under high water level is too big,and the largediameter uplifting force resistance pile is usually set in the middle of the bottom plate as the stress fulcrum to reduce the thickness of the plate.However,when the station is buried deep and located in the rock stratum,the cost of the station increases and the construction diffi culty increases.In view of these problems,based on a practical design case study of a long-span column-less station in Xuzhou,this paper proposes to adopt the small-size uplifting force resistance pile scheme to solve the stress problem of bottom plate of the columnless station,and compares it with the conventional large-diameter uplifting force resistance pile scheme from the perspectives of cost effectiveness and applicability.The results show that the small-size uplifting force resistance pile scheme reduces the cost,reduces the construction diffi culty,shortens the construction period,and some of the difficulties in the application of column-less station in high water level stratum are avoided.