Overall Seismic Performance Analysis Of Rigid Pile Composite Foundation-Raft Foundation-Upper Structure

Rigid pile composite foundation is a new type of foundation treatment method with maincharacteristics of making soil between piles could play a better role through the adjustment ofcushion, so as to achieve the purpose of piles and soil interaction function. The compositefoudation can greatly improve the bearing capacity of foundation, and the settlement isrelatively small. Rigid pile composite foundation has been applied to super-tall and highbuilding structure in recent years. Especially in the karst district,the application of rigid pilecomposite foundation get an excellent effect, which producing enormous economic and socialbenefits.The theoretical research of rigid pile composite foundation is still difficult to meet therequires of engineering practice. Especially research on the seismic performance of compositefoundation is very inadequate, for the reason that there are security risks in the engineeringpractice of rigid pile composite foundation, which not only affects the further development ofthe theory and practice of the composite foundation, but its further promotion and application.Based on the method of soil-structure dynamic interaction, overall finite elementdynamic time history analysis of rigid pile composite foundation-raft foundation-upperstructure were analyzed, then summarized the characteristics of the seismic performance ofrigid pile composite foundation from the results. The main factors affecting the seismicperformance of composite foundation were also considered. The specific include thefollowing aspects of content:1) Present the method of finite element and infinite element coupling to achieve the soil-upper structure dynamic interaction analysis, exploring the key technical approach of solvingthe rigid pile composite foundation system dynamic interaction, which based on ABAQUS.2) Seismic numerical modeling of free field was analyzed by using different analysissoftware and both of the calculation results were comparedï¼›then based on the test of theliterature as an example, the finite element analysis method is proposed in this paper fornumerical simulation, through comparing numerical simulation results and experimentalresults show that this proposed finite element modeling method is feasible and correct.3) Principle cushioning effect of Rigid pile composite foundation is preliminary analyzed.Comparing with the results of rigid pile composite foundation as well as ordinary piled raftfoundation finite element dynamic time history analysis, including the dynamic response ofraft foundation, piles and upper structure, summarize the characteristics of the seismicperformance of rigid pile composite foundation. 4) Research the influence of some of the main factors in the composite foundationsystem on the overall seismic performance of the rigid pile composite foundation. Thesefactors include the thickness and modulus of cushion, pile diameter and pile spacing, soilstatus, and the level of earthquake intensity.According to the results of finite element dynamicanalysis, obtain the influence degree and laws of these factors on the overall seismicperformance of the rigid pile composite foundation, and give some meaningful specificsuggestions to practical engineering.