Study On The Lateral Load Experiment Of Part-bonding Prestressed Uplift Pile And Aplication

This article takes the uplift project static load experiment of Beijing Fruit Company storehouse and logistics center (logistics exchange hall and its storehouse) as a background, analyzes and researches into the bearing capacity, the deformation, the quantity of lift and the development mechanism of skin resistance of part-bonding prestressed uplift Pile.This article first introduces the load transmission mechanism of the single equal section uplift pile and the definitive method of the uplift-pile'bearing capacity. And on the basis of the above mentioned, it further discusses the influencing factors of the pile anti-pull bearing capacity.This article next discusses the classification of uplift pile. According to this discussion, this article respectively makes analyses and conclusions on the pre-stressed and the non-pre-stressed uplift pile as well as the stress mechanism and the working characteristics of uplift pile and anti-pulled out the anchor rod; Also, base on the uplift project static load experiment of Beijing Fruit Company storehouse and logistics center (logistics exchange hall and its storehouse), the author increases a body reinforced concrete strain test experiment :(1) According to the static load test data, the paper analyses the Q-S curve, S-lgt curve and S-lgQ curve of the pre-stressed and the normal uplift-pile's load experiments. Compared with theirs similarities and differences, it makes the validity check on " It's feasible to enhance the bearing capacity to its maximum while unchanging the shape of pile body section." ; (2)Draws up the uplift pile axle force - depth curve and the skin resistance-depth curve and to analyze the characteristics exerted by axles strength transmission and the skin resistance; (3) In the equal section single pile research pattern, according to the test result, the author brings forward the single pile limit bearing capacity forecast formula and the corresponding deformation formula combined with the limit bearing capacity computation model, and makes some calculations, analyses and validity check by using these test data; (4) By analyzing the pre-stressed uplift pile body stress and the concrete stress, the author indicates the merits and demerits of part-bonding prestressed uplift Pile. Lastly, the author does the economic analysis of an application case of the uplift project of Beijing University foreign students'apartment.Finally, the author comes to some conclusions that have guiding significance to the similar uplift pile's design, construction and further research in the future. As follows: (1) Enhance the nature of pile physical strength. Enhance the anti pulled-out mechanical property through the pre-stress to the pile exerted by the pre-stressed steel stranded wire which is preset in the pile; (2) Change the stress route. Through the pre-left free section of steel stranded wire to make the force exerted on the bottom of pile so as to avoid the invalidation of the normal uplift pile caused by cracks of the concrete on top of the pile due to the excessive uplift force; (3) Enhance the bearing capacity. With unchanging the shape of pile body section,it is feasible to enhance the pile bearing capacity to its maximum; (4) Save the cost. In terms of stress, the pilebody concrete's intensity doesn't need to be designed as the high grade. In terms of structure, applying the pre-stressed high tensile steel stranded wire in uplift pile could effectively enhance the pile's stiffness, reduces reinforcement element, its body size and saved the investment thereby.