The Y-shaped Sink Pipe Pile Composite Foundation Characters And Optimal Design Method

Post-construction settlement was the main problem for expressway built in soft groud. Y-style vibro-piles was a new technique in composite foundation. The equipment of pile mechanism and construction technology were hold the line; This technique had biggish value to spread and application. This paper was based on the application of the y-style vibro-pile in expressway. Load transfer mechanism was studied by geotechnical engineering software FLAC^3D. The theory of the settlement calculated was analyzed which considered the influences of upper and lower penetration into the cushion and the underlying substratum, the main research results were obtained:1. Based on the analysis of the y-style vibro-pile field monitoring data, the settlement regularity and the changing of the pile-soil stress ratio and pore water pressure are obtained.2.Base of the predecessor, this paper trace the origins of y-style vibro-pile-soil stress ratio under the flexible foundation.3.The composite modulus of y-style vibro-pile isξmultiple than the natural compression modulus.4. Based on the reseach of y-style vibro-pile working mechanism by FLAC^3D, the load transfer mechanism and the changing of pile axial force and the skin friction are obtained. Based on the study of the y-style vibro-piles, the changing law of the pile-soil stress ratio by differents of the ratio of pile-soil modulus and the pile length is obtained5. Based on the study, the settlement control optimization design method which could increase the pile spacing is proposed in this paper. The optimum theory is applied to solute this mothod.