Study On The Non-linear Properties Of Pile Based On P-Y Curve Model

The researchers of different countries have more and more thought much of the researches of static and dynamic mechanics characteristics for pile foundation bearing horizontal load or moment. The pile foundations of inshore projects such as ocean flat often bear the intense combined actions of wave load, ice load and wind load, etc. These environment loads make remarkable horizontal load which would lead to evident displacement. For horizontal static load and circular load, P-Y curve can preferably reflect the non-linear characteristics of pile foundation. Moreover, calculation and analysis of pile foundation horizontal vibration is the core of the whole aseismic design in aseismic calculation for high, weighty and large buildings. Static analysis is not enough to project design. Therefore, transverse dynamic characteristics of pile foundation have increasingly been taken into account. In dynamic research, not only the development law of horizontal displacement and stress but also frequency correlation, resonance and other nonlinear characteristics should been researched. Pile foundation structures in inshore projects and seaport projects would go into nonlinear state and endanger the safety of the structures under the atrocious and intense ocean dynamic load. Therefore, it is necessary that nonlinear characteristics of pile bearing dynamic load should be thought much of and lucubrated.In this thesis, nonlinear dynamic mechanics theory is applied to analyze nonlinear mechanic model of single pile bearing transverse load in order to find out the leading factors which affect mechanics behaviors of single pile bearing transverse load. The combination of theory analysis and numerical simulation shows the rationality of the theory and the reliability of numerical simulation.The research and characteristics of this thesis follow as:(1) This thesis researches the inter-action between pile and soil, specially discuss how to apply P-Y curve to calculate the soil around pile model. Characteristics of soil around pile is correctly simulation and the reactivity of soil around pile to pile is effectively taken into account. The model of soil around pile, such as continuous medium theory method, Winkler ground beam model method, finite element method, boundary element theory method and P-Y curve method, is analyzed and correctly chosen.(2) This thesis discusses analysis and calculation methods of single pile and group piles under horizontal load, calculate and analyze pile foundation's deformation and bearing capacity under horizontal load from upper structures or soil compression.(3) This thesis discusses how to apply P-Y curve to solve pile deformation, rotation angle, moment and pile shearing force under horizontal load, analyze the difference between P-Y curve method and elastic ground reaction method, research P-Y curve method characteristics in the calculation of bearing horizontal load pile and find correct method to choose calculation parameters of P-Y curve.(4) This thesis researches P-Y curve discount coefficient calculation method of group piles under horizontal load. The behavior characteristic of group piles under horizontal load is different from that of single pile under horizontal load, the difference lies mainly in that while space between piles in group piles is less than critical pile interspace, the piles in group piles would bring group piles effect through soil between piles.(5) This thesis researches transverse vibration of piles with nonlinear constitutional equation, and the top of piles is bearing transverse dynamic load, dynamic moment and damping nonlinear elastic soil mass. Firstly, I assume that pile materials are viscoelastic material with some equation. The material elastic equation is cubic nonlinear equation, and viscosity equation is linear. Then I solve control equation, a nonlinear partial differential equation, which is used to analyze nonlinear dynamic behaviors of pile foundation. Secondly, I use Galerkin method to predigest the control equation and gain a predigested dynam...