Stress And Deformation Characteirstics Of Long-short-pile Composite Foundation By Numerical Analysis

The long-short-pile composite foundation as one of many new types ofcomposite foundation is used more and more extensively in civil engineeringbecause of its remarkable economic and social benefits. However, present theorystudy on work mechanism of long-short-pile composite foundation is not deeply,so some more researches need to be done. The long-short-pile compositefoundation is mainly used in building projects at first. Afterwards it is graduallyapplied to ground treatment for flexible foundation, such as embankment. Butthe stress and deformation characteristics in flexible foundation is different fromthat in rigid foundation. So the theory in rigid foundation cannot be directlyapplied to flexible foundation. In this paper, the stress and deformationcharacteristics of the long-short-pile composite foundation were studied relyingon a high-rise apartment building in Wuhan by using numerical simulation. Thefollowing works are done:(1) Summarized the study present state of the long-short-pile compositefoundation.(2) Generated three-dimensional model of long-short-pile compositefoundation by FLAC3D, then doing loading test. Verify feasibility of FLAC3Din study long-short-pile composite foundation. Get the change rule of stress distribution under foundation, settlement, axial stress of pile and pile-soil stressratio with the increase of load.(3) From cushion and pile two aspects, analyzed effects of parameters onthe long-short-pile composite foundation settlement, axial stress of pile andpile-soil stress ratio.(4) Compared the change rule of stress distribution under foundation,settlement, axial stress of pile and pile-soil stress ratio with the increase of loadunder flexible foundation and rigid foundation without cushion. And analyzedthe different utility of cushion in flexible foundation and rigid foundationfurther.