Study On Pile-soil Stress Ratio And Load Transfer Characteristics Of Cast-in-situ Concrete Thin Wall Pipe Pile Composite Foundation

Thin-wall pipe pile using cast-in-place concrete (abbreviated named PCC) technique is a new ground improvement technology developed independently by Geotechnical Research Institute of Hohai University. As a new ground treatment method, it is widely used in the ground improvement in east China coastal area. At present it is used in the form of piled-supported composite foundation, the effect turns out to be in good quality. While the mechanical property of PCC pile composite foundation is not clear, especially under embankment in the expressway. The study is launched to address the mechanics property of PCC pile composite foundation. Following are the main works fulfilled.1. Based on the field test results of Yan-tong expressway, static load test and field test are conducted in a typical section. The mechanics properties of different kind of foundations are obtained.2. Based on the pile-soil-embankment-cushion common working mechanism, the balance condition of stress-deformation coordination considered, a calculation model is established. And the effect of parameters of model on the stress ratio is studied.3. Using finite analysis software ADINA, a typical single PCC pile composite foundation model is established. And the influence factors on the mechanics property are conducted.4 With the same cross area and pile length, the mechanics properties of PCC pile and common cast-in-place pile composite foundations are compared. The results indicate that PCC pile composite foundation has high bearing capacity and better in settlement controlling.