Dynamic Response Analysis Of Pile-supported Wharf Structure Under Earthquake Action

As the gateway of ocean transportation,port is the link between water transportation and land transportation.With the continuous development of Chinese economy,the demand for import and export trade is increasing year by year,and the construction scale of ports is also expanding.The pile-supported wharf has been widely recognized in the field of port construction because of its many advantages,such as less material,small excavation and good berthing conditions.With more and more pile-supported wharves being put into use,the design requirements of pile-supported wharf are gradually improved.Earthquake is one of the main reasons for pile-supported wharf damage.In recent years,seismic damage cases of pile-supported wharves are still common despite the relevant technologies are developing.It is more and more important to study the seismic performance of pile-supported wharves from multiple angles and depths.In this paper,a numerical model of the soil-piled interacting wharf structure is established with the help of Midas GTS NX.The model size is 170×40m,and five straight piles are laid out on the wharf.The main research contents are as follows:(1)By adjusting the type and amplitude of seismic waves,the time-history analysis of acceleration,velocity and displacement of the pile-supported wharf panel structure and pile foundation structure were carried out,and the results were compared.Furthermore,the soil parameters and ground motion intensity were selected as the sensitivity influencing parameters,and the reference error and grey correlation analysis were carried out to explore the sensitivity for peak acceleration and extreme lateral displacement of the soil around the pile,the sensitivity for dynamic internal forces of the pile top and the pile body to each parameter under earthquake action.On the whole,the difference sequence of the grey correlation between the acceleration and lateral displacement of the soil feature points is great,while the difference sequence of the grey correlation between the structural feature units is small.(2)The maximum strain of pile foundation in soil was used as the damage index to classify the damage grade of pile-supported wharf structure,and the vulnerability curves of pile-supported wharf structure were obtained based on IDA analysis method and PSDA linear fitting method,and then the structural failure exceedance probability under the action of different levels of ground motion intensity were analyzed.The research shows that with the gradual increase of PGA,the probability of the structure being basic intact becomes smaller and smaller,and the probability of damage at various levels increases successively.In addition,the more uncertainty factors are considered,the more inclined the vulnerability curves will be,and the knowledge uncertainty factors will have an impact on the probability assessment of structural risk of pile-supported wharf.(3)According to the parameters selected above,a orthogonal experiment of four factors and five levels was designed,and the strain calculation model of BP neural network pile foundation was built with the help of MATLAB neural network toolbox,so as to solve the problem of large consumption of numerical calculation in the process of seismic vulnerability analysis.On this basis,the network calculation results were compared with the finite element numerical simulation results.The results showed that the precision of the network model was good,and it can be used to replace a lot of finite element numerical calculation,which can save working time and improve working efficiency.