Seismic Response Studies Of High-pile Wharf Based On Pile-soil Interaction

A wharf of a port plays an important role in social economy and the development of foreign trade. Pile-supported wharf is a form of structures,which applies to be built in soft foundations. The pile-supported wharf has big load-bearing capacity, needs less sand and less gravel, as a result, it is widely used in deep water ports. However, the pile-supported wharf used to be severely damaged by the earthquake, leading to huge economic loss and bad social impact. Currently, the seismic response studies on pile-wharf structure in the domestic are mainly based on the quasi-static method, which is not enough to reflect the dynamic characteristic about the pile-soil interaction. This paper established a finite element model of a pile-supported wharf, which took into account of soil-pile-structure dynamic interaction. The following aspects and results were mainly studied in this paper:(1) The seismic damage and seismic damage methods in pile-supported wharf structure have been summarized, and analysis model and analysis methods considering pile-soil interaction have been studied, as well as nonlinear constitutive relation of soil and concrete,integration methods of dynamic equilibrium equation. Both modal analysis and seismic responses of single pile and group pile finite element modes have been analyzed,and in comparison with test results,it indicates that numerical simulation method proposed in the paper is feasible.(2) According to a real example, a 3D elastic-plastic finite element model of pile-supported wharf based on pile-soil interaction has been established, which considers nonlinear characteristics of soil and concrete and other factors. The method of time-history analysis was used to the seismic response analysis of the high-pile wharf structure.(3) The influence factors of seismic response, which include seismic spectral characteristics, seismic intensity , pile spacing, pile diameter were discussed by controlling variables method. The thesis has also summarized the regular pattern..(4) Three-dimensional viscous-spring artificial boundary (VSAB) has been modeled in the numerical analysis model in order to study seismic response of pile-supported wharf,which takes elastic recovery stiffness and radiation damping of infinite foundation into consideration. Comparing with those calculated in the large boundary fixed conditions, it shows that the displacement and acceleration responses of wharf structure are smaller under VSAB, and more closely to actual situation. VSAB can be an effective method for seismic response numerical analysis of pile-supported wharf.