平板锚基础在砂土地基中抗拔承载力

Uplift bearing capacity of plate anchor foundation in sand

摘要:

准确预测砂土中平板锚的抗拔承载力,对海上浮动可再生能源装置的锚泊稳定性评估具有重要意义,为此,基于二维有限元技术,采用修正Mohr-Coulomb（MMC）本构模拟中密-密砂的应变软化行为,并利用开发的用户子程序,研究条形平板锚基础在砂土地基中的抗拔承载力。通过与有关理论解及其他离心机试验结果的对比分析,验证有限元模型的可靠性。一系列参数分析表明,平板锚的埋置深度对抗拔承载力有较大影响,与H/B=1相比,H/B=10处承载力系数高273%；砂土相对密度越大,抗拔承载力越大；致密砂（D_r=100%）和松砂（D_r<33%）相比,承载力系数提高25%；平板锚的摩擦因数对抗拔承载力系数几乎没有影响。根据数值模拟的结果,对平板锚基础在中密及密砂地基中不同深度处的抗拔承载力系数公式进行校正,为平板锚基础在中密砂以及密砂地基中的应用提供了理论依据。

Abstract:

Reliable estimation of the uplift bearing capacity of plate anchor in sand is significant for predicting the mooring stability of floating renewable energy devices on the sea. On the basis of two-dimensional finite element method, a modified Mohr-Coulomb (MMC) constitutive model was employed to simulate the strain softening behavior of medium dense and dense sand, and the corresponding user subroutine was developed to examine the uplift bearing capacity of strip plate anchor foundation in sand. The rationality of the finite element model was verified by comparison of theoretical solutions and other centrifuge tests results. Through a series of parametric studies, results show that the embedded depth of plate anchor had great influence on the uplift bearing capacity of the plate, and the bearing capacity factor at H/B=10 was 273% higher than that at H/B=1. The larger the relative density of sand was, the larger the uplift bearing capacity was. Compared with loose sand (D_r<33%), the bearing capacity factor of plate in dense sand (D_r=100%) increased by 25%. The frictional factor of plate anchor had little effect on the uplift bearing capacity factor. On the basis of the numerical simulation results, a corrected formula of uplift bearing capacity factor of plate anchor at different depths in medium dense and dense sand was proposed, which provides a theoretical basis for the application of plate anchor foundations in medium dense and dense sand.