Seismic Response Analysis Of Deep Foundation Structure Based On Ground Surface Seism Input

Pile foundation has been used to consolidate soft ground for a long history, and it is also one popular means to be used to improve foundation today. Many pile foundations are damaged seriously during the past major earthquakes. Large amount of cost will be paid to remedy the defect of pile foundation undergoing earthquakes, so it is a significant value for both academic and concrete project to study the subject of numerical analysis of Soil-Pile-Structure Dynamic Interaction under seismic loading. Based on the review of past research work, a state-of-art with respect to Soil-Pile-Structure Dynamic Interaction, which includes inversion analysis, pile analysis models, analysis methods, is presented and analyzed firstly. Research work is conducted in light of the processes as follows:(1) The paper formulates horizontal displacement equation of upright shear wave in linear visco-elastic soil which is assumed to be horizontally layered, and makes an inversion analysis in frequency domain based on wave theory. Fourier transform is applied to transform the earthquake acceleration records measured from the ground surface from time domain to frequency domain and the earthquake acceleration records are made inversion computation in frequency domain, and the earthquake accelerations of any soil layer (or bed rock) below ground surface are gotten. Results indicate that, when the seismic wave passes through the soil layers, the wave shape don't change basically, but the amplificatory effect on seismic wave of soil layer is evident. The effect on acceleration is different with the change of depth of rock. And the maximal value of acceleration will increase with the augmentation of depth of bed rock.(2) To model nonlinearity and hysteretic character of soil under seismic loading, the p-y curve of single pile under monotonic loading is used as the skeleton curve and modified Ramberg-Osgood model theory is employed to construct the hysteretic loop for single pile dynamic p-y curve. The improved model is used in the Dynamic Beam on Nonlinear Winkler Foundation method. Both material and hysteretic damping of soil are taken into consideration. The governing equation of motion is set up combining with theory of FEM, and a computation program is written based on above theory. A comprehensive parametric study is also done for shear type structure supported by a...