Research And Analysis On Driving Effect Of Prestressed Concrete Pipe Pile In Soft-soil

Pile are now widely used in civil engineering, especially in soft clay foundation, because they have various advantages. However, when the pipe pile are installed into the ground, the same volume of soil will be displaced, and the pore pressures will be developed around the piles. That will result in the influence on the surrounding soil and nearby structures. Many researchers studied the problem, but they did not get completely satisfied results up to now for the complication of the problem. On the basis of the work available, the author has further studied the problem of the soil squeezing effect with new approaches. The main work includes:Firstly, according to the actual engineering, I put forward the research background, so this paper summarizes the past's researching result to the driving effect of pipe pile. The statistics show that soft clay's structural characters have remarkable effect to the pipe pile's driving effect. Accordingly, when driving pile in the soft clay, we should consider the influence of soil structure.based on these study production, this paper choose the tri-linear softening model.Secondly, based on the tri-linear softening model and the fundamental principles of soil plastic mechanics, In this paper, the stress solutions of plastic zone and limit expansionary compression values have been obtained. Furthermore, the variation of soften coefficient of soil and the effect of the different soil parameters on plastic zone radius and limit expansional compression using finite element analysis. Stress field of soil around pile under different soften coefficient and its spacial distribution rule are also addressed. at the same time, based on the solutions of the stress have been deduced previously, and adopting the Henkel's formula. The relationships between pore water pressure and coefficient of soil structural strength damage and depth are also presented.Thirdly, this paper sum up some defendable measures of driving effect in the practice. and combining a engineering in Xiaoshan city to prove this measures are right and available.Finally, this paper count and conclude 118 cases of static load test results in Taizhou, it presents the change tendency of load carrying capacity with different pile length, pile radius and under-pile soil property.