Three Dimensional Finite Element Analysis Of Response Of The Building Adjacent To Deep Excavation In Soft Soil Area

Based on considering the small strain stiffness behavior of the soil, the 3D finite element models including the excavation and the building are built. The necessity of considering the initial differential settlement of buildings is discussed, while the buildings with different wall stiffness and different storeys are analyzed. The response of buildings adjacent to excavation with different deformation modes of retaining wall is researched. Meanwhile, for the building with arbitrary angle or adjacent to the excavation corner, the impact of excavation which is related to the distance and the angle between the building and the retaining wall or the excavation corner is analyzed. Through the above analysis, the characteristics of the deformation of the building caused by the excavation are studied in depth, and the main conclusions are as follows:(1)When the latitudinal walls of building is perpendicular to the retaining wall, it is necessary to consider the initial differential settlement of the building. When the longitudinal walls of the building are perpendicular to the retaining wall and are located over the lowest point of the settlement trough, taking account of initial deflection is necessary. When the longitudinal wall of building is perpendicular to the retaining wall and are located over the hogging zone of the settlement trough, taking no account of initial deflection is conservative.(2)When the building locates over the lowest point of the settlement trough and the number of building storeys is greater than 4, the deflection and the tensile strain remain constant. In this case, the lowest building is in the most adverse situation. When the building locates over the hogging zone of the settlement trough, the tensile strain of 3-storey building reaches the maximum value and the 3-storey building is in the most adversity.(3)For the kick-in and convex deformation of the wall, the sagging deformation is the most significant and the tensile strain on the building is severe. In this case, the building close to the excavation is in the most adverse situation. For any deformation form of the retaining wall, when the relative distance between the building and the excavation is about (1~1.5) times the excavation depth, the buildings located in this position are in most adversity. (4)When the deflection deformation becomes the major cause of the tensile strain, the maximum tensile strain occurs on the longitudinal walls perpendicular to the retaining wall. In this case, the longitudinal wall perpendicular to the retaining wall is in most adversity. When the deflection deformation is slight, the deflection deformation and torsion deformation cause the tensile strain together. In this case, the longitudinal wall perpendicular to the retaining wall is not in most adversity.(5)When the longitudinal walls of the building are parallel to the retaining wall and the distance between them is smaller than the excavation depth, the corner effect has negative influence on the controlling of deformation of the building. The building is in the most adverse situation for this case. When the longitudinal walls of the building are perpendicular to the retaining wall and the distance between them is smaller than the excavation depth, the corner effect has a positive influence on the controlling of deformation of the building, and obviously reduces the tensile strain of the wall. However, the building is in the most adverse situation where the tensile strain reaches the maximum value.