考虑冲刷的单桩水平极限承载力预测模型研究

Study on Prediction Model of Ultimate Lateral Bearing Capacity of Monopile Considering Scour

冲刷对海上风电单桩基础的水平承载力影响显著,目前缺乏长径比对冲刷下单桩水平承载力的影响规律研究。开展冲刷下单桩水平受荷数值模拟,研究长径比对冲刷下单桩水平极限承载力的影响规律,结果表明:(1)冲刷深度为0.5D,1D和1.5D时,相较于无冲刷情况,单桩水平极限承载力分别下降至少16%,29%和40%;(2)提出单桩水平极限承载力弱化因子η量化长径比对冲刷下单桩水平极限承载力的影响规律,当长径比L/D<10时,弱化因子η随长径比L/D的增加而增大,在长径比L/D≥10时,弱化因子η趋于稳定;(3)基于弱化因子η构建考虑冲刷的单桩水平极限承载力预测模型,预测结果的相对误差小于8%。该模型能为海上风电项目中单桩基础设计提供理论参考。

Scour has a significant effect on the lateral bearing capacity of offshore wind power monopile foundations.At present,there is lacking of research on the effect of the slenderness ratio on the lateral bearing capacity of monopile.Numerical simulations were carried out to study the effect of the slenderness ratio on the ultimate lateral bearing capacity of monopile considering scour.The results indicated that:(1)When the scour depth was 0.5D,1D,and 1.5D,the ultimate lateral bearing capacity of monopile decreased by at least 16%,29%,and 40%,respectively,compared with that without scour.(2)The effect of the slenderness ratio on the ultimate lateral bearing capacity of monopile considering scour was quantified by the proposed weakening factorη.When the slenderness ratio L/D was less than 10,the weakening factorηincreased with the increase of the slenderness ratio L/D.When the slenderness ratio L/D was equal to or greater than 10,the weakening factorηtended to be stable.(3)The prediction model of the ultimate lateral bearing capacity of monopile considering the scour effect was built based on the weakening factorη.The relative error of prediction results was less than 8%.This prediction model can provide a theoretical reference for the design of monopile foundations in offshore wind power projects.