Experiment Study On The Unbonded Post-tensioned Prestressed Cast-in-situ Uplift Pile

At present, the anti-floating security issue in Engineering has become increasingly prominent. As the main form of anti-floating foundation, the uplift piles have the uplift bearing capacity and durability of a higher demand. Applying prestressed technology to cast-in-situ uplift pile, in addition to a good solution to pile body cracking resistance and effectively control the top of the pile pulling displacement, but also to maximize the pile shaft resistance. You can control the crack increasing and bearing capacity while reducing the steel consumption. So prestressed cast-in-situ uplift piles have uplift piles with low cost, high capacity, good durability.To further study the differences of anti-pulling performance between the application of Prestressed Technology in the cast-in-situ uplift pile and common cast-in-situ uplift pile. Through several anti-pull type of pile-field Comparative Experiment on the tensile loading at the top of pile, prestressed piles and uplifting loading at the tip of pile, this paper analysis the differences among the crack resistance, bearing behavior, internal force of pile body and loading transfer mode.Through summing up the construction of pile applying prestressed technology Foundation in the current engineering practice, the post-tensioned and unbonded tendon prestressed technology in the cast-in-situ pile is developped, and the feasibility of the construction technology have been verified by construction and test.By the static loading test piles of several types of uplift foundation piles, this paper discusses the influence on the pile shaft resistance by the Poisson effect and the effect on uplift shaft resistance distribution suffered by the different location of the force point.The internal forces of pile body have been tested through laying the testing components.analysis of prestressed piles, the load transfer behavior, the distribution of the shaft resistance and working characteristics of crack resistance have been analyzed. pressure type underpinning pile load transfer traits, pile side work on the distribution and crack resistance characteristics. Using the finite element simulation, several types of piles have been computationally simulated.In this paper, a comprehensive comparison of several types of uplift pile bearing capacity, durability, economic indicators and their applicability and application conditions, stating the prestressed pile to pile on the technical feasibility and economic superiority as uplift and further promote the technology, application recommendations.By a comprehensive comparison of several types of uplift pile on bearing capacity, durability, economic indicators and their applicability and application conditions, stating the prestressed pile to pile on the technical feasibility and economic superiority as uplift have been stated and make recommendations on further promoting and applying the technology.