富水砂层地铁换乘车站施工对既有车站影响研究

Study on Influence of Existing Subway Station During Construction of Transfer Subway Station in Water-Rich Sand Layer

依托实际工程,采用流固耦合的数值分析方法,并结合现场实测数据,对比研究富水砂层地区换乘车站施工期间,不同降水深度和开挖方式对既有车站的影响规律。结果表明:基坑降水的渗流固结作用有利于缓解坑底土体因开挖卸荷和围护结构挤压引起的隆起,考虑基坑降水的数值计算结果更接近实际值;基坑降水有利于抑制坑底隆起,对于变形要求相对严格的工程,可适当增加坑底降水深度来控制既有车站上浮量;对于一侧开挖面积较小的十字换乘车站,对称开挖对竖向位移的影响不大,但对水平位移影响较为明显。

Based on the actual project,the fluid-solid coupling numerical analysis method and the field measured data are adopted to comparatively study the influence law of different precipitation depths and excavation modes on the existing stations during the construction of transfer stations in the water-rich sand layer area.The results show that the seepage consolidation effect of foundation pit dewatering is beneficial to alleviate the uplift caused by excavation unloading and the extrusion of the enclosure structure,and the numerical calculation results considering foundation pit dewatering are closer to the actual value.Foundation pit dewatering is helpful to restrain the uplift of the pit bottom.For the engineering with relatively strict deformation requirements,the dewatering depth of the pit bottom can be appropriately increased to control the uplift of the existing station.For cross transfer station with small excavation area on one side,symmetrical excavation has little effect on vertical displacement,but has obvious effect on horizontal displacement.