Research On The Engineering Property Of Problem PHC Pile

PHC pile, as its full name is pretensioned spun high stregth concrete pile, is a new kind of prefabricated pile appeared a few years before. Compared to other kinds of piles, this kind of pile's construction is easier, faster, safer and cheaper. So it is widely applied in and abroad. As it's applied in our country of a few years, it has got a huge benefit. And it has also appeared many problems. At present, the study for the problem PHC pile is very little, and it is almost the summarization of the engineering experience. So, if we can fully understanding its bearing property, it will be a great help for the disposal and reuse of the problem PHC pile.Firstly, this thesis introduces the theory bases of this thesis. It mainly includes: the finite element method (FEM) software-ABAQUS, linear elasticity model, Mohr-Coulomb plasticity model, concrete damaged plasticity model, and the cells for numerical analysis.Then, this thesis generalizes the present application condition of Ningbo area. And introduce the usual problem during the PHC pile's application. It almost includes such instance: the pile is sloping; the pile is broken; the pile can't get the level designed before; the pile has been driven up; the pile's top or the pile's other part is splitting; the pile itself is disjointed, and so on. And this thesis also introduces the reason for the problem and the ways of disposal. This thesis especially recommends two disposal methods for broken PHC pile: rectification-joining method and high pressure grouting method.After that, according to the engineering practice, the engineering property of the sloping PHC pile is analyzed. Based on the numerical analysis, when the PHC pile is sloped, it will influence the pile's settlement little. But horizontal displacement of the pile will increase when the pile top's horizontal displacement increases. So, when the PHC pile is sloped, under the vertical load, it will emerge a great horizontal load to the soil around it. And it also may push the piles around it to be broken.Finally, according to the engineering practice too, the engineering property of the broken PHC pile is analyzed. The bearing capacity of the broken part is analyzed firstly. According to that, this thesis talks about the reasonable length of the core and get a few of conclusions. Then, this thesis analyses the engineering property of the reinforced broken PHC pile when the pile is vertical and horizontal. This thesis also analyses its bearing capacity under horizontal load, and find out something too. After the broken PHC pile is reinforced, it can satisfy the design demand of the settlement, but its bearing capacity of horizontal load decreases greatly. When the pile is sloping, it will appear a great horizontal displacement under the vertical load. And it will influence its stabilization and emerge a great horizontal load to the soil around it.