The Experimental Research And Analysis Of The Stress Distributed Partially Prestressed Uplift Pile

This paper takes the Beijing shijingshan Galactic Business District K Block C2 Commercial Financial Projects(hereinafter referred to as "Business Financial Projects") background of the compressive static load test of single pile. Due to the larger field test load, low preloading method feasibility, so the experiment takes anchor reaction force device to provide vertical pressure. We analyzed the bearing capacity, deformation, uplift capacity and the development of resistance mechanism side of the stress-dispersed portion bonded prestressed uplift(float) single pile,by monitoring the stress on the anchorage reinforcement. And the test verify that the force of stress-dispersed portion bonded prestressed uplift(floating) pile is reasonable.Firstly, The study introduces the research status of pile pullout mechanism by theory studies, experimental studies and numerical analysis at home and abroad. It follows the factors that effect bearing capacity of uplift pile, and the like cross-section transfer mechanism and ultimate bearing capacity determination method of single uplift(float) pile. Followed by pre-stressed, non-prestressed and partially bonded prestressed uplift(floating) piles were introduced. Based on field test data analysis,we can make the decentralized part of the bonded prestressed stress uplift(floating)pile load test curves of Q-s and s-lgt, Verifing this view " changing the pile stress state by adjusting the strand binding site of prestressing uplift(floating) pile, can maximize the lateral friction"; We analyzed prestressed uplift(floating) load transfer path and the fundamental mechanism of pile according to the curves that plotted uplift(floating) pile axial force and lateral friction with depth with experimental data; We analyzed the situation of prestressed uplift(floating) concrete piles force, pointing out the advantages and disadvantages of the stress-dispersed portion bonded prestressed uplift(floating) pile.Finally, Concluded this article, we draws some construction what has guiding significance for the design of against pulling(floating) pile:(1) Setting a plurality focus artificially of uplift stress-dispersed portion bonded prestressed uplift(floating)pile, change the force path of the pile and improve the pulling resistance of pullout(floating) pile;(2) Distinguished from ordinary pile, The axial force of prestressed uplift(floating) concrete pile changes slowly with depth, as a result concrete is noteasy to crack, provide the good quality of piles what are used as engineering piles after the completion of the experiment;(3) If we use heaping test to complete the static load test of Business Finance Project, which would make a huge cost. After the end of the test the anchor pile can also be used as an engineering pile, which is greatly saving the cost.