The Research On Plugging Effect Of PHC Statically-Pressured Pipe Pile

In the paper,we introduces the research status of plugging effect and its deficiencies and pointed out that the change situation of plugging height reflects end resistance of plugging inner frictional resistance and the shear strength of plugging balance between relations. The change situation of plugging height is the core of the research on the mechanism of plugging. This paper measured plugging height test of more than200statically-pressured pipe piles and plugging height change situation of more than20statically-pressured pipe piles. Combined with other literature research results we found that pile of section size is the main factors which influence plugging the height. In this paper we set up the experience formula between PLR(Plug Length Ratio) and the section size of pile. Introducing wedge theory to describe the formation process of plugging in order to revise the IFR (Incremental filling ratio) and PLR(Plug Length Ratio). Through the calculation about the plugging we found that using IFR to determine plugging end resistance is feasible. And set up the empirical formula to converse PLR and IFR.In this paper the author established the calculation formula based on plugging effect of vertical bearing capacity of a single pile. By comparing the characteristic value of the shaft resistance from the 《Technical specification for prestressed concrete pipe pile foundation》 in Liaoning Province, the 《Technical specification for prestressed concrete pipe pile foundation》 in Tianjin and the 《Technical code for building pile foundations》. The author modify the characteristic value of the shaft resistance in the 《Technical specification for prestressed concrete pipe pile foundation》 in Liaoning Province.This paper count more than50statically-pressured pipe piles according to test pile separately according to the formula in 《Technical specification for prestressed concrete pipe pile foundation》 and the new based on plugging formula of the vertical bearing capacity of a single pile.Through the contrast of calculation result and measured result,the author the new based on plugging formula of the vertical bearing capacity of a single pile is more appropriate.