Applicability of p-y curves for large-diameter steel pipe piles in clay
Large-diameter steel pipe pile is the most commonly used foundation form for offshore wind turbines.Its horizontal bearing performance is the most critical aspect in the design of wind turbine structures.The p-y curve method,recommended by API specifications,is the mainstream approach to calculate the horizontal bearing capacity of steel pipe piles.However,further investigation is required for its applicability to large-diameter rigid piles and rigid-flexible piles.Through numerical simulation methods,this study investigated the deformation characteristics of horizontally loaded piles with different length-diameter ratios,and the failure patterns of surrounding soil.A criterion was proposed to determine the flexibility of piles based on the length-diameter ratio.The applicable range of the traditional p-y curve was obtained by comparing the horizontal ultimate bearing capacities of steel pipe piles with different length-diameter ratios.The results indicate that the traditional p-y curve model,which only considers horizontal soil resistance,is suitable for calculating the bearing capacity of rigid-flexible and flexible piles with length-diameter ratios greater than or equal to 15.However,for rigid short piles with a length-diameter ratio less than 9,the error can be as high as 63%,significantly underestimating the horizontal bearing capacity of individual piles.For rigid-flexible piles with length-diameter ratios between 9 and 15,the API specifications can be taken as a reference in calculation.