海洋工程中桩基抗拔承载力研究

抗拔承载力是桩基设计的重要组成部分,随着海上风电场的建设,海洋工程中出现了越来越多需要提供足够抗拔力的抗拔桩。现有规范中桩基抗拔承载力的计算来源于对抗压承载力的修正,理论研究成果也仅限于半经验法及极限平衡算法,因此与实测数据存在较大差异。系统阐述现有的桩基抗拔承载力计算方法,并结合实际工程计算桩基的抗拔承载力,对比各种计算方法的结果发现:黏土中API规范法计算的桩基上拔承载力更接近实测值;Meyerhof和Das算法适合计算长径较小的桩;Chattopadhyay和Shanker算法适用于砂土中抗拔桩的计算;现有抗拔承载力计算方法忽略了黏土中的黏附力和负孔隙水压力,导致计算结果与实测值偏差较大。

Study of the Uplift Bearing Capacity of Pile Foundationsin Ocean Engineering

Uplift bearing capacity is an important part of pile foundation design. In ocean engineering, there is a growing demand for piles that have enough uplift bearing capacity for construction in offshore wind farms. The method for calculating the uplift bearing capacity of pile foundations given in current codes is rooted in the modification of the compressive bearing capacity of pile foundations, and the theoretical research is limited to semi-empirical and limit equilibrium methods. Therefore, there is big difference between calculated and measured values. This paper systematically explains the current calculation methods for the uplift bearing capacity of pile foundations, then uses different methods combining them with practical projects. The results show that:the uplift bearing capacity calculated by the method given in the API code is closer to the measured value in clay; the Meyerhof and Das algorithms are ideal for uplift piles with a small length-diameter ratio; and Chattopadhyay and Shanker''s algorithms are suitable for piles in sand. We also found that the current methods for calculating uplift capacity ignore the adhesion force and negative pore water pressure, resulting in great differences between calculated and measured values.