A Modified P-Y Model for Small Diameter Rigid Piles of Photovoltaic Supports in Sand
Pile foundations are the most commonly used foundation forms of terrestrial photovoltaic supports,which mainly bear horizontal loads.The analysis method for horizontal bearing characteristics of pile foundations normally in use at present is the p-y curve method recommended by American Petroleum Institute(API).To research the applicability of the p-y curve method recommended in calculating deformation of small-diameter rigid piles acted by horizontal loads,a three-dimensional finite element numerical model of small-diameter rigid piles with four different pile diameters was constructed based on a photovoltaic project.The horizontal bearing characteristics were analyzed and the p-y curves of pile foundations at different depths were obtained.On that basis,a modified p-y curve calculation model of small and medium diameter single piles in sandy soil was proposed considering pile diameters and depths.The results indicated that the horizontal displacement of small diameter rigid piles was inversely proportional to pile diameters,and the influence of pile diameters on pile bending moment was not significant.Compared with numerical simulations,the initial stiffness calculated by the p-y curve recommended by API was larger and the ultimate soil resistance was smaller,the p-y curre method recommended by API was not suitable for calculations of small-diameter rigid piles under horizontal loads.Based on the numerical simulation results,the relation equations among pile diameters,depth and initial foundation stiffness or ultimate soil resistance were fitted,and a modified model of the p-y curve was established.The modified model was verified that agreed fairly well with the actual values.
photovoltaic pilep-y curve methodsandfinite element calculationsmall-diameter rigid pile
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