Study On The Characteristic Of The Uplift Capacity And Deformation Of Tension Piles

With the development of municipal engineering and the constrctions of more and more underground structures, how to resist the uplift loading has become a problem often encountered in engineering design and construction. Although tension piles have been widely used to resist the uplift load, but the relevant theoretical study is still far behind of engineering practice.In this thesis, a study is made on the characteristic of the uplift capacity and deformation of tension piles. The main work of the thesis includes:1. Based the research fruit of tension piles so far available, the methods for analyzing bearing capacity of single tension pile with equivalent section and with enlarged tip are summerized and discussed.2. The defomation behavior of tension pile with equivalent section or with enlarged tip is investigated. The analytical relationship between uplift load and elastic dislacement of tension pile with enlarged tip is derived. Moreover, the revised method of deformation harmonious is proposed and utilized to predict the nonlinear displacement of tension piles with equivalent section or with enlarged tip, and the theoretical predictions are compared with the field measurements.3. A simplified method based on the PS curve from field test is proposed for predictiong the nonlinear displacement of tension pile group. In this method, the tension piles are assumed to be the interacted nonlinear springs and the nonlinear relationship between pile and soil is simulated by the hyperbolic function obtained from fitting PS curve. Meanwhile, the interaction between piles is analyzed by interaction factors. Further more, the theoretical predictions are also compared with the field measurements to verify the simplified method proposed.The study made in this thesis enhances the cognition to the behavior of uplift capacity and deformation of tension piles and provides a good reference to the design of tension piles.