3D Finite Element Analysis On The Influences Of Surcharges And Foundation Excavation On The Stability Of Neighboring Pile Buildings

With the economic development and the urbanization of our country, newly built high buildings are springing up in the urban areas. As the development planning, cash flow and estate development are not synchronized, and other reasons, many foundation pits are excavated among dense high buildings. During the process of excavation, the removed earth placed beside the buildings nearby is a common phenomenon. Aimlessly removed earth without scientific planning and analysis can easily result in the destruction of nearby buildings and underground structures. The impacts of the removed earth placed beside the nearby buildings are not specified in any relevant regulations. Some related regulations mention that removed earth placed beside the foundation pit is prohibited, but there is not any specification in terms of its distance from its nearby buildings and the height of the removed earth. The research in this field is far from enough. Further studies should be carried out in the aspects of removed earth laced beside buildings, the impact of building gravity loads on excavation support, foundation excavation, the influence of removed earth piled on its surrounding buildings, and the impacts of both the removed earth and the buildings themselves on the deformation process of the building foundation.The software ABAQUS is used in this thesis to make the three-dimensional finite element simulation analysis on the construction process of excavation and bulldozers. The main research work and the conclusions of this thesis are as follows:1) Based on reviewing related literature and the studying of various calculation methods in terms of the impact of the excavation on the soil outside the pit, and the removed earth placed besides surrounding buildings, the author makes a three-dimensional finite element simulation on a real estate foundation pit. After the analysis of the impacts of the removed earth placed at the opposite side of nearby buildings on the building foundation, the author figures out the depth of the foundation pit, which can guarantee the safety of the building foundation, under the condition that the removed earth is placed five meters away from its nearby buildings.2) The finite element simulation analysis is adopted to analyze the impacts of three factors on the pile foundation of existing buildings respectively. These three factors are the excavation of different depths of foundation pits, different heights of removed earth, and the distance between existing buildings and removed earth.3) The author analyzes the impacts of both foundation pit excavation and removed earth beside the deformation of building foundation, and figures out the appropriate distance between the removed earth and its surrounding buildings and the appropriate heights of removed earth under the condition of different depths of excavation.4) Two programs are provided in this thesis to reduce the impacts of the removed earth on its surrounding buildings:to lower the height of the removed earth by enlarge its basal area, and to strengthen the supporting structure. In addition, the efficiency of these two programs are verified and it turns out to be effective in reducing the impacts of the piling earth on its surrounding buildings.