深圳软土地区地下盖挖地铁停车场桩基工程实践

Pile foundation practice of metro parking lot in Shenzhen soft soil stratum

大面积填海区淤泥地层基坑地基沉降变形较难控制,目前常见的地基加固措施采用复合地基,一旦复合地基工法选择不当或施工控制不当,容易产生较大的工后沉降。本文以深圳地铁13号线内湖停车场项目为背景,重点针对填海淤泥地层盖挖逆作地下结构桩基、地基加固等关键问题进行了研究,构建了针对深厚淤泥地区基坑“盖挖逆作+疏桩基础+复合地基”的综合安全技术体系,盖挖逆作工法确保了深大基坑的水平变形控制要求;疏桩基础+复合地基既解决了淤泥施工过程承载力要求,以及盖挖逆作工法的承载力要求,同时满足地下停车场运营期间的承载力和沉降变形要求,研究成果可为同类工程提供参借鉴。

It is difficult to control the settlement and deformation of foundation pit in silt stratum in large-area reclaimed area.At present,composite foundation is often used for foundation reinforcement.Once the construction method of composite foundation is improperly or the construction control is improper,it is easy to cause large post construction settlement.Taking the Neihu parking lot project of Shenzhen Metro Line 13 as the background,this paper focuses on some key problems such as the underground behavior in covered top-down excavation in reclaimed silt stratum.A comprehensive technology system of‘covered top-down excavation+sparse pile foundation+composite foundation’was proposed in deep silt area.The covered top-down excavation ensures the horizontal deformation requirements of deep foundation.Combined sparse pile foundation+composite foundation not only solves the bearing capacity requirements of sludge,but also meets the bearing capacity and settlement deformation requirements during the operation of underground parking lot.The research of this work can provide some references for similar projects.