Study On Vibration Response Of Igh-speed Railway Subgrade And Shock Absorption Of Pile Barrier

The construction of high-speed railway has spread all over China,but our country has a vast territory and complex geological structure.The way to deal with the lack of bearing capacity of soft foundation is to set up concrete piles,and China is a country with many earthquakes.By setting up the structure of concrete piles in the foundation,on the basis of meeting the bearing capacity of subgrade,the damping effect of concrete piles in subgrade is studied.In this thesis,the vibration response law and damping performance of high-speed railway subgrade under pile barrier structure are studied by experiment and numerical simulation.The research idea in this thesis is as follows: through theoretical analysis,the propagation mechanism of seismic waves and damping measures are studied,and it is concluded that the horizontal seismic waves have great influence on the damage of subgrade,especially the influence of surface waves,and the soft foundation in subgrade is often strengthened by setting piles.Therefore,this thesis studies the damping effect of barrier pile under the action of surface wave and horizontal seismic wave respectively by experiment and finite element method,and analyzes the vibration response law of high-speed railway subgrade under the action of horizontal earthquake.The main conclusions of this thesis are as follows:(1)The input mode of artificial boundary and ground motion in finite element analysis is studied by theoretical method,and the seismic wave data is inverted.(2)In the experimental study on the vibration of barrier piles to surface waves,the pile length and pile spacing are important parameters that affect the propagation of seismic surface waves.(3)Through the finite element verification of vibration test,the similarities and differences of shock absorption data of barrier pile under the action of seismic surface wave between test and finite element method are analyzed,and the shock absorption law of barrier pile under seismic surface wave in test method is verified.(4)In the study of dynamic response of subgrade under horizontal earthquake by finite element method,the vibration response laws of piled and non-piled subgrade on its slope and inside are compared and analyzed.The dynamic response law of subgrade slope and its interior,as well as the acceleration,velocity and displacement response law of pile body are obtained.(5)In the finite element study on the damping of subgrade by barrier piles under horizontal earthquake,the damping effects of barrier piles on subgrade slope and interior are analyzed under the variables of pile length,pile spacing and pile diameter.The subgrade structure with concrete barrier piles has a certain damping effect.(6)By comparing the damping effects of two types of waves,the damping effect of barrier piles on surface waves is obviously better than that of horizontal seismic waves.