Low Strength Piles Composite Foundation Stability And Deformation Calculating Method Study

Low strength pile composite foundation increases the foundation bearing capcity, decreases the foundation settlement, and enhances the foundation stability by the piles replancement. Low strength pile is the plain concrete pile, including cement mixing pile; cement morta pile; high-pressure rotary jet grouting pile; CFG pile etc., which strength is lower then reinforced concrete pile. The low strength piles foundation display the complicated engineering character, for the variety of strength and construction technology.This paper uses theoretical calculation method; numerical simulation analysis method; in-situ obversion method, integrated analysis the low strength pile foundation piles, reinforced cushion, soil among piles, upper load effect in the whole low composite foundation system,during the different forced periods and different position.Based on the low strength piles composite foundation deformation model, a group of deformation and stability calculating equations on the low strength piles composite foundation is put forward. During the equations derivation, the interaction between the piles-soil-cushion is considered, and the stress-strain compatible equations are constructed. At the same time, the piles-soil stress ratio and the equal-settlement-surface analytical solution are also received. Further more, the piles and their surround soil stress distributing regulation, compress deformation, and the up-stick-deformation of the cushion and the lower-stick-deformation of the soil are all obtained. Through the summary of composite layer settlement and the piles surround soil compress deformation, the whole settlement of the composite foundation is deduced. The piles stability and flexibility are analyzed by the elastic foundation beam theory. The soil among the piles, winding pile failure is analysised by the Mohr-coulomb model on the upon stress condition. The stress-strain compatible equations are used in the engineering by diagrammatized. The foundation settlement and sability regulation are researched through the elastic-plastic finite element method, which includes plain concrete smeared cracking model. Theoretical calculation and numerical simulation result are proved by the embankment test section.