Interaction Analysis Of High-rise Buildings Piled Raft Foundation

Piled raft foundation is the main form of foundation used in high-rise buildings.The foundation,soil and superstructure are a unified whole,and the three influence and interact with each other.The research on the interaction of foundation,soil and superstructure has achieved certain results,but there are many factors affecting the interaction of the three,and the study of its mechanism is not clear enough,and further research is needed.This paper summarizes the research results of the theory of interaction at home and abroad,and at the same time deeply understands the mechanism,analysis method and theory of interaction.Using the finite element program ABAQUS,a three-dimensional finite element model of the superstructure-piled raft foundation-soil is established.The pile raft foundation is analyzed for interaction.Mainly studied : Comparison of traditional design and superstructure-piled raft foundation-soil interaction design;Study the influence of soil elastic modulus,raft thickness,pile length,and pile diameter on superstructure and foundation;Influence of soil elastic modulus,raft thickness,pile length,pile diameter on superstructure and foundation under earthquake.Through research:(1)it is concluded that compared with the interaction analysis,the traditional design method has certain unreasonable points: the traditional design method fixes the lower part of the upper structure without considering the influence of the foundation settlement on the upper structure,and the bending moment of the beam is smaller than that of interaction;It’s unsafe;At the same time,when designing the foundation,the influence of the upper structure was not considered.Raft stress obtained by traditional design method is too large,and the design was conservative;when designing high-rise buildings,considering the interaction can make the design more reasonable.(2)The modulus has a great influence on the settlement of the raft,reducing the differential settlement and the maximum settlement of the raft;the increase in the thickness of the raft can increase the stiffness of the pile-soil system and improve the differential settlement,but it increases the overall settlement of the raft.The increase of pile length and pile diameter changes the load bearing ratio of pile-soil and makes the pile bear more load.(3)When considering the interaction,under the effect of an earthquake,the increase in soil elastic modulus,pile diameter,pile length,and raft thickness will increase the overall rigidity of the structure and increase the internal force of the structure,which will reduce the maximum settlement and differential settlement.It will also reduce the horizontal displacement of the top layer of the superstructure.