Researches On The Prestressed Spun Concrete Square Pile Techniques

Prestressed spun concrete square pile (simply named PS) is a new type of piles developed by China Academy of Building Research (attachment A) . In recent years, prestressed pipe pile (simply named PP) becomes more and more popular day by day in China. But PS pile system has many advantages compare with PP pile.Based on PP pile research work, to address questions on the designing, application, and standard of PS pile, a series of theoretical analysis and field experiment were carried in a building site in Kunming city, the author makes some suggestions which can serve reference for further project engineering. The main contents of the current research are as follows:1) A new pile style-PS is developed. The manufacture method and technical characteristic are introduced in detail.2) Field experiment study and application on PS pile are introduced in detail in the thesis. The test program is similar to construction process. The application of PS in building projects is described in detail. The experience can be used as a reference to other projects. Based on the tests in situ, the parameter of pile installation is presented in the thesis. It is shown that the PS pile has great practical value.3) The design and calculation methods of PS pile are studied. A simplified method of bearing capacity of PS is proposed. In the methods, the interaction between the soil plugs is considered. Calculation formulae study has been made by the simplified method. The results indicate the method is more convenient to be used in engineering design.4) The product standard and drawings of PS pile are introduced in detail. Application and development of PS pile will be improved by implementation of product standard of PS.PS has bright market prospect. But many problems and topics remain open and need further research on its theory and application in China.