Application of foundation reinforcement by anchor-jacked piles under low clearance

For the a building with 13 floors high and no basemnt located in Shanghai, short leg shear wall system is used for the superstructure, and the foundation beams with precast tubular piles are used to be the foundation type. Before service of the project, may soils are pulled behind the building, and large deformation of the building is induced. For safety consideration, anchor-jacked piles are used to be as the foundation reinforcement. The steel pipe piles are used, which are the same as the existing ones. The total number is 116. In order to strengthen the rigidity of the original foundation and to make it easier for pile layout and load transfer, the raft with thickness of 700 mm is hoped to connect the existing foundation beams and the new piles. The steel pipe piles are located under the raft, and the raft will be the counterforce structure for the anchor-jacked pile. The connection node between piles and raft and that between raft and the existing foundation beams are proposed herein. The equipment is reformed to realize the construction of anchor-jacked piles under the clearance less than 2.5 m. So far, the maxium settlement of the building is about 10 mm, which shows the effect of the reinforcement by the anchor-jacked piles is remarkable.