Improved p-y curve models for large diameter and super-long cast-in-place piles using piezocone penetration test data

Abstract

Due to rapid population growth and infrastructure demand in China, more effective use of existing land is required. Infrastructure construction in coastal regions has driven rapid economic development. With increasing numbers of port facilities, cross-sea bridges and offshore engineering projects, large diameter and super-long cast-in-place piles are increasingly needed in these regions. The p-y curves of piles are key to evaluating their horizontal bearing characteristics, which is critical to the risk evaluation, design and construction of large infrastructural supports. In the present study, a p-y curve analysis method based on piezocone penetration test (CPTu) data is proposed, which uses the Matlock and hyperbolic p-y models. The relationship between CPTu cone tip parameters (qt, u2 and qe) and p-y curve parameters (pu and y50) is established. Moreover, the deformation and mechanical characteristics of large diameter and super-long cast-in-place piles in the Yangtze River floodplain are analysed thoroughly. The feasibility and reasonability of the proposed p-y curve method based on CPTu test data are verified through numerical simulation and horizontal load field tests. A hyperbolic p-y model based on CPTu test data is applicable to sandy soils, while a Matlock p-y curve model based on CPTu test data is applicable to cohesive soils.