Three-dimensional Finite Element Analysis Of Seismic Behavior Of Soil-cement Pile Composite Foundation

Soil-cement pile composite foundation is one of the subrigid pile composite foundation,which is suitable for soft soil area.China’s vast territory,the distribution of soft soil is more extensive,so more and more soil-cement pile composite foundation is used in engineering construction.At present,the research on the bearing capacity and settlement deformation of the composite foundation under the static action is relatively mature,but the research on the seismic performance of the composite foundation is relatively few,and the research methods and means are single,mainly focusing on the shaking table test and finite element numerical simulation.Due to the universality of the application of rigid pile composite foundation,scholars have made some progress in the research of its seismic behavior.The rise of soil-cement pile composite foundation is relatively late,so the research on its seismic performance is lacking.Because the shaking table test needs a lot of manpower and financial resources,the research method chosen in this paper is finite element analysis.Combined with the existing research,it is found that the two-dimensional numerical simulation of soil-cement pile composite foundation is relatively perfect,and the three-dimensional seismic analysis of soil-cement pile composite foundation with ABAQUS finite element software is rarely carried out.To this end,the feasibility of using ABAQUS finite element software to study the seismic behavior of composite foundation was verified by using the existing relevant conclusions.On this basis,according to the requirements of certain similarity ratio,the constitutive model of materials is selected reasonably and the three-dimensional model of soil-cement pile composite foundation is established.A viscous boundary condition is set for the soil and seismic waves are input horizontally from the bottom of the model.At the same time,in order to ensure that the soil meets the equilibrium and yield conditions,the ground stress equilibrium analysis is carried out.In addition,through modal analysis,the natural vibration frequency of the calculated system is obtained,which is used as the frequency value for damping calculation.After applying El-Centro wave and Taft wave with different amplitudes to cement-soil pile composite foundation,the dynamic response of cement-soil pile and foundation soil under the action of two different seismic waves are compared and analyzed,and the horizontal displacement characteristics of cement-soil pile and foundation soil are studied.Finally,the general rule of dynamic response change and horizontal displacement characteristics of soil between piles in cement-soil pile composite foundation under the action of earthquake are obtained.