Numerical Simulation Of The Effects Of Mudcake And Bottom Sediment On Bearing Behavior Of Cast-in-place Piles

It is common that some of pile foundations contain defective piles in engineering of pile foundations,especially bored piles in clay when construction. The usual form defect of piles include the party necked-in of piles , shaft mud cake and bottom sediment, etc. Nowerdays the numerical simulation of working behaviour and mechanism of the pile foundation with single defective pile are not too much. It is still on the breakway phrase, In this article, we first analyse the load-bearing behavior and the working mechanism of single pile with defect under vertical loadings.In this article, we analyse the load-bearing behavior and working mechanism of single pile with defect under vertical loadings with the method of three- dimesional finite element,the defects include shaft mud cake and bottom sediment.then, through comparing with the relevant result of single pile without defect, we conclude the working characteristics of single pile with defect under vertical loadings,and through comparing the curve of P-S of single pile with different defect with single pile without defect ,we conclude the working behavour of single pile with shaft mud cake and bottom sediment.And through comparing the distribution of the pressure on the different depth of pile, the changing of tip resistance of pile with the vertical loadings and the changing of side frictional resistance force of pile with the vertical loadings.we conclude the working mechanicsm of single pile with different defect relative to the single pile without defect. The research reveals the regularity of the effect of the defect contributing to the whole load-bearing characteristic of single pile foundation. In the research ,we investigate the parameter of the defect pile include the thinkness of the shaft mud cake ,the cohesion magnitude and the friction angle magnitude of the shaft mud cake,the thinkness of the bottom sediment ,the cohesion magnitude and the friction angle magnitude of the bottom sediment.The main effect of the shaft mud cake is that it depressing the side frictional resistance of piles, The main effect of the bottom sediment is that it depressing the tip resistance of piles.It contains important guiding significance to the analysing and estimating the characteristic of load-bearing of the whole single pile foundation and the engineering technique to deal with it when the defective piles are detected.