Analysis Of Pile Under Inclined And Eccentric Loads In Layered Soils And Research In Model Test

Behavior of Bridge piles loaded vertical, horizontal, eccentric and other complex loads, is much more complex than the behavior of piles only loaded vertical or horizontal loads. Integrating with project "Study on the design theory and numerical analysis for the bridge pile in steep slope" supported by National Natural Science Foundation of China, research about behavior and analysis method of pile foundation under inclined and eccentric loads considering P-? effects, has been done in the paper, which is of theoretical and practical value. Firstly, behavior, bearing mechanism and influencing factors of piles under inclined loads are systematically discussed based on summery of research on pile under eccentric and inclined loads home and abroad. Secondly, it is assumed that bedding value distribution function in a single layer is C(z)=mz+C, and accordingly power series solution is presented for displacement, stress and soil pressure calculation of pile under eccentric and inclined loads in layered soils, and then a corresponding computer program 'Inclinsys' is developed. Thirdly, horizontal displacement of pile is assumed to have a longitudinally cubic power function, and accordingly improved pole element rigid equation well considering P-? effect is derived integrating with moment/horizontal-displacement relationship and shear/horizontal-displacement relationship both derived in power series solution, and then improved finite pole element method is developed. A corresponding computer program 'Plisys' has been developed which can be applied to displacement and stress calculation of pile in layered soils under inclined and eccentric loads, moment, pile gravity, horizontal distributed loads, vertical distributed loads, scattering vertical forces and soil-pile friction. Fourthly, model tests of eight flexible timber piles in three groups have been done to study the effects of free length above ground, pile rigidity and slight inclination to behavior of pile under eccentric and inclined loads, and the theoretical results fit the test results well. Finally, semi-empirical formula for displacement calculation of piles under eccentric and inclined loads are presented based on theoretical analysis and test results analysis, and some beneficial conclusions have been reached.