Effect Of Layered Sand Liquefaction On Seismic Response Of Continuous Girder Bridges

Bridge pile foundation was built on the soft ground at present,which was one of the most commonly used foundation form.this foundation can well adapt to various geological conditions,high bearing capacity,good stability,low sedimentation value,etc.Sand soil in the strong earthquake is one of the main form of failure caused by liquefaction,sand liquefaction induced lateral extension of the influence of the pile foundation involves the undrained soil characteristics,soil structure change,dynamic load,the nonlinear response of pile,soil and the foundation and experience of complex stress and strain,etc.,this is a very complicated problem.Recently,several major earthquakes earthquake damage survey that pile foundation are vulnerable to earthquake damage result from liquefied soil.In order to discuss the earthquake response of the sandy soil liquefaction of continuous girder bridge,the influence of the comparative study of the existing various pile-soil interaction the applicability of the simplified analysis method in the sandy soil liquefaction,putting forward the corresponding simplified analysis model considering effect of sand liquefaction,this paper made the following work:(1)adopting several kinds of simplified analysis model is commonly used in current engineering: built-in method,block bottom consolidation method and “m” method,the traditional “p-y “curve method,6 x6 concentrated soil spring method,etc.,under the condition that the effect of sand liquefaction is not considered.a continuous girder bridge longitudinal and transverse bridge seismic response has carried on the contrast research,analyses the displacement,shear force and bending moment response of the bridge pier,as benchmark of comparative study on the follow-up effect of liquefied soil.(2)the proposed modified p-y curve method considering soil liquefaction effect,set up the limit of the soil near the liquefied soil lateral resistance strength of “pu” and the initial stiffness “kT” reduction calculation formula,and the detailed modeling process is given.modified p-y curve method is used to study the effect of the earthquake response of the sandy soil liquefaction about continuous girder bridge,bridge piers and the bending moment,shear force and displacement of pile distribution,and compared with traditional several simplified analysis method.(3)the parameter sensitivity analysis is used to study the earthquake under the sand soil layer thickness and buried depth on the seismic response of the continuous girder bridge,the paper mainly discusses the piers and pile foundation key seismic internal force anddisplacement changing with soil layer thickness and buried depth,so as to sandy soil layer of pile foundation in seismic and reinforcement is designed to provide the reference.