Research Of Method For Settlement Calculation And Back Analysis Of Tall Building-Foundation-Soil

The foundation of tall building is the most important structure constitute part of the tall building. Considering relatively high requirements of deformation and capacity as the big load on the ground, projects often use pile-raft (box) foundation. The pile can transfer load to the underground space in the appropriate soil or the soil around pile to meet the requirements of settlement and stability of the building. For all long, however, the performance of interaction and deformation characteristics and many other issues have not been able to properly solve because of the complexity of the settlement theory about pile-raft (box) foundation. It is no time to delay that refining the design method for settlement calculation of tall buildings to lead a more rational guidance as the pile-raft (box) foundation are present used widely. Therefore, the settlement research of the high-rise building on the foundation is very necessary and valuable.Belowing is the main research work:First, this paper sums up several major existing methods for settlement calculation of high-rise building, and describes the selection of foundation models. According to the mechanism of pile settlement deformation, the characteristic of soil's deformation among piles and the overall foundation soil deformation is analyzed and discussed, and the settlement calculation method is proposed on the basis of studying of the value Lc of simulated pile-bottom position shifting on and impact depth Zn of the settlement calculations. In addition, the selection of compression modulus Es, deformation modulus Eo, unloading modulus Et, rebound modulus Er and compression modulus after rebounded modulus Ers are summarized and discussed, and also present some good advice on it properly.Secondly, a high-rise building project is modeled by using FLAC 3D software, and simulated the entire process of construction to the foundation settle stably to get the changes of situation about the stress and strain. By analyzing the deformation of pit soil and the settlement of foundation soil observed, the simulation results is conformable in line with monitoring settlement data and demonstrates the selection of the Lc value and Zn value in the settlement calculation method suggested is very reasonable for this example. Meanwhile, this project is calculated by using the suggested method, and the results show that the calculated settlement value approachs relatively to the actual settlement value. Moreover, comparing to the other results calculated by several other calculation methods, this result is the closest value to the actual value.Finally, using the BP network numerical algorithm of artificial neural networks by MATLAB software works on a settlement displacement back analysis of the project and achieve the target of reasonable geotechnical parametersμ, Es, C,φvalue, and give a guidance for forecasting and selecting geotechnical engineering parameters in future.