锚杆静压桩在低净空条件下既有建筑地基加固中的应用

发布时间：2019-03-08 19:27

【摘要】：上海市区某13层建筑,无地下室,上部结构为短肢剪力墙体系,基础采用墙下预制混凝土管桩。该项目正式投入使用前在其背后大量堆土,导致建筑产生了较大的整体水平变形。为消除安全隐患,采用锚杆静压桩进行地基加固。加固钢管桩的桩长、单桩承载力、桩数都与原有桩基相同。在原基础梁之间的房间区格内设置700 mm厚筏板,新增的钢管桩布置于筏板下,通过筏板实现对上部结构的支承作用,筏板也同时作为静压桩施工的反力结构。为确保荷载传递的可靠性,提出了钢管桩与筏板,以及筏板与原基础梁之间的连接做法。另外,由于结构底层净空受限,通过改造,使得压桩设备可在低于2.5 m左右净空条件下完成钢管桩的压入施工。目前该建筑最大沉降10 mm左右,表明地基加固的作用是有效的。
[Abstract]:A 13-story building in Shanghai has no basement. The superstructure is a short-leg shear wall system and the foundation is made of precast concrete pipe piles under the wall. Before the project was put into use, a large amount of soil was piled on the back of the project, resulting in a large horizontal deformation of the building. In order to eliminate the hidden danger of safety, anchor static pressure pile is used to reinforce the foundation. The pile length, bearing capacity and pile number of reinforced steel pipe piles are the same as those of the original piles. A 700 mm thick raft is set up in the room area between the original foundation beams, and the new steel pipe pile is placed under the raft. The raft supports the superstructure through the raft, and the raft is also used as a counterforce structure for the construction of the static pressure pile at the same time. In order to ensure the reliability of load transfer, the connection method between steel pipe pile and raft, as well as between raft and original foundation beam is put forward. In addition, due to the limitation of the bottom floor clearance of the structure, the pile pressing equipment can complete the pressure construction of the steel pipe pile under the condition of less than 2.5 m clearance. At present, the maximum settlement of the building is about 10 mm, which shows that the effect of foundation reinforcement is effective.
【作者单位】：华东建筑设计研究院有限公司上海地下空间与工程设计研究院;
【基金】：上海市科委科研项目(15DZ1204000)
【分类号】：TU753.8

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