Study On Simplified Calculation Method Of Bridge Considering Pile-Soil Dynamic Interaction

The pile-soil dynamic interaction problem of bridge under earthquake is very important.At present,there are mainly theoretical analysis methods and experimental research methods for studying the pile-soil dynamic interaction.The simplified calculation method of dynamic p-y curve is widely used in engineering practice and research because of its clear physical concept and simple calculation.The commonly used experimental methods deduced the dynamic p-y curve due to large manpower and material financial needs,long test cycle,and inconvenient parameter analysis,which limits the application of experimental methods.With the continuous improvement of the power calculation method and the computer level,a simplified model considering pile-soil dynamic interaction which is based on numerical method is put forward.A numerical integral model considering the pile-soil dynamic interaction is established by ABAQUS finite element software.The procedure and method of deducing the dynamic p-y curve from the integral model are introduced,and a simplified model considering the pile-soil dynamic interaction is established.The seismic responses obtained by different methods of single pile are compared.Simplified model of bridge large diameter pile is established,and the response of single pile and pile groups under different conditions is compared.The influence of relevant parameters of dynamic p-y curve and pile groups are analyzed by comparing seismic results and differences of models.The paper main contents are as follows:(1)Based the equivalent uniform viscoelastic artificial boundary mehtod,the single pile intergral model is established by ABAQUS finite element software.The soil is modeled by Mohr-Coulomb constitutive material and the pile soil contact is set.The method of deducing the dynamic p-y skeleton curve by intergral model is expounded.The dynamic p-y skeleton curve is established by hyperbolic form.The p-y skeleton curve of API specification and the p-y skeleton curve obtained are compared to verify the feasibility of numerical method for obtaining dynamic p-y curves.(2)Based on the dynamic p-y skeleton curve deduced by numerical method,the spring damping system is introduced to simulate the nonlinear resistance and damping energy dissipation of soil.The simplified single pile model considering the pile-soil dynamic interaction is established by ABAQUS finite element software.The applicability of the simplified model is verified by comparing the seismic response of shaking table model,the simplified model and the integral model.(3)Based on a continuous beam bridge as the engineering background,the integral model and simplified model of large diameter single pile are established.The applicability of the large diameter pile simplified model is verified by comparing the seismic response of the integral model and the simplified model under the condition of single sand layer soil and multi-layer soil.The parameter analysis of sand dynamic p-y curve,including the initial stiffness ratio of pile and soil,superstructure weight,sand density and effective diameter of the pile is performed,to understand the influence of related parameters on the sand dynamic p-y curve and to provide some suggestions on dynamic p-y research curve for subsequent researchers.(4)Based on the continuous beam bridge as the engineering background,the integral model and simplified model of pile groups considering the pile-soil dynamic interaction are established.The seismic response results of the two numerical models are compared in the single sand layer.The pile groups parameters including superstructure weight,pile spacing and pile diameter are analyzed.The response rules of pile groups under earthquake action is summarized.