扩底抗拔桩在天津于家堡南北地下车库中的应用

于家堡金融起步区充分利用地下空间实现交通、商业功能的提升,由于地下结构埋置深、地下水埋深浅,地下工程抗浮问题十分突出。在建的南北车库为纯地下结构,单层面积达3×104m2,埋置深度达16 m。开展了扩底抗拔桩与桩侧后注浆抗拔桩两种新型抗拔桩的现场足尺试验,试验结果表明,两种新型抗拔桩皆适用可行,抗拔承载力较常规等截面桩大幅提高,且本扩底抗拔桩试桩的极限承载力与变形控制皆优于桩侧后注浆抗拔桩。本工程选择了扩底抗拔桩并采用可视化全液压扩底施工工艺,新型抗拔桩大幅减短桩长,节约大量材料并减少泥浆排放,经济社会效益显著。扩底抗拔桩的成功应用为其在该地区的推广奠定了基础,具有较高的工程示范价值。

Application of pedestal uplift piles to Yujiapu north-south undergound garage in Tianjin

There is a great development of underground space in the Yujiapu area, in Tianjin. The problem of anti-float is serious, because of the buried depth of the basement is deep and the groundwater table is higher. The monolayer area is about 30,000 m2; and the buried depth of the basement is about 16 m. Based on the Yujiapu north-south underground garage, the tests on pedestal uplift piles and side-grouting uplift piles are canied out. The tests show that, compared with the normal uplift piles, the pedestal uplift piles and side-grouting uplift piles have advantages of greater uplift bearing capacity and shorter pile length; so that its economic benefit is notable. The pedestal pile is better than the side-grouting piles in the aspects of ultimate bearing capacity and displacement controlling. The pedestal uplift pile is used in the garage; full hydraulic swivel-driven construction technology is used too. The successful using of the pedestal uplift piles has great significance and practical engineering value; it will be a good practical case for similar projects.