English：

Based on excavation construction of the Donghai Road Drainage Pipe Network ReconstructionProject in the Tianjin Binhai New Area, on⁃site monitoring and numerical simulation were carried out toanalyze the development law of horizontal displacement and surface settlement of foundation excavationretaining pile, and to study the influence of different pile diameter, pile spacing and embedded depth onthe deformation characteristics of foundation excavation. The results indicate that the horizontaldisplacement of the retaining pile increases with the increase in the excavation depth, increasing first andthen decreasing along the depth direction, and the horizontal displacement of the pile at the depth of 10mis the largest. The horizontal displacement of the pile at the long side of the foundation excavation islarger than that at the short side. During the excavation, the surface settlement is dominant, and themaximum surface settlement is generated at a distance of 7. 5m from the edge of the foundationexcavation. When the distance from the edge of the foundation excavation is more than 30m, basically nosurface settlement occurs. The increase in pile diameter and embedded depth of retaining pile reduces thehorizontal displacement of pile and surface settlement, and the increase in pile spacing makes thehorizontal displacement of pile and surface settlement larger. When the pile diameter of the retaining pileis 1 200~1 400mm, the pile spacing is 1 000~1 500mm, and the embedded depth of the retaining pilein the three⁃layer structure section and the five⁃layer structure section is not less than 4m and 2. 5m,respectively, the deformation of the foundation excavation can be well controlled.