Showing papers by "Fu-Ping Gao published in 2016"

Scour effects on p-y curves for shallowly embedded piles in sand

Abstract: Soil scour around a shallowly embedded pile can significantly compromise its lateral response, reducing both stiffness and capacity. Estimation of the lateral pile response must take into account both the scour-hole geometry and the overconsolidation effects on the remaining soil. A series of centrifuge model tests with various scour profiles were conducted at a scale of 1:250 to investigate the effects of both local and general scour on the response of a laterally loaded pile. Measured pile moment distributions and force–displacement data at the pile head were used to derive p–y curves quantifying the lateral pile–soil interaction. The p–y curves derived from various scour profiles were compared for equivalent depths below the new scour base, and below the original soil surface. For the general scour cases, the p–y curves for given depths below the post-scour surface are essentially identical to those at the same depths without scour. In contrast, for the local scour cases, the p–y response at a given de...

Pipe-soil interaction model for current-induced pipeline instability on a sloping sandy seabed

Abstract: As offshore exploitation moves to deeper waters, ocean currents become the prevailing hydrodynamic loads on pipelines, and at the same time a sloping seabed is always encountered. The prediction of...

Numerical study of local scour effects on the lateral pile-soil interaction

Abstract: Local scour usually occurs around offshore pile foundations, which may bring the reduction of both the effective stresses in the surrounding soil and the effective pile embedment. Until now, the effects of local scour on the lateral pile-soil interaction have not been well understood. In this study, a 3-D finite element model for the lateral pile-soil interaction is proposed and verified with experimental results. An improved analysis approach is further presented for evaluating the local scour effects on the lateral pile-soil interaction by extracting p-y curves from the numerical results. The results indicate that scour could induce a significant transition of pile behavior for a monopile typically employed for offshore wind turbines. If the pile exhibits rigid structural behaviors after scour, the pile’s tip and shaft resistance may become a significant component of the whole soil resistance, which would render the traditional p-y approach inapplicable. For a given depth below the scour base, the p-y curves get significantly stiffer with increasing scour depth, especially at relatively shallow depths. The scour effects on the variation of p-y curves from the present numerical results are generally consistent with the existing centrifuge results. As the slope angle of scour holes decreases, the effect of the remaining sloping overburden soil above the level of the scour base reduces and the stiffening of the p-y curves at a given depth below the scour base is correspondingly alleviated.