以砂土地基中吸力桶为分析对象,建立能够考虑主应力方向旋转的本构模型,通过数值分析方法进行积分,在不同荷载倾斜角度条件下研究等效塑性应变分布及土体主应力方向的旋转变化,分析倾斜荷载对吸力桶承载性能的影响。研究结果表明:等效塑性应变主要在桶壁外围和桶端下部等区域集中分布,桶体内部土体处于弹性变形状态;荷载倾斜角度对竖向荷载-位移关系的影响比较微弱,对水平荷载-位移关系的影响则比较显著;土体主应力方向在变形初期的旋转非常显著,随着倾斜角度的增加,主应力方向的旋转逐渐显著;当竖向位移在(0.05～0.10)D范围时,主应力方向达到稳定状态,不再旋转。

The impact of inclined loading on bearing capacity of suction caissons over sand foundation is investigated by establishing an ideal elasto-plastic constitutive model which takes the rotation of principal stress direction into consideration. Through numerical integration, the variation in principal stress direction during shear deformation is obtained, and moreover, the influence of inclination angle of load on distribution of equivalent plastic strain is examined. Research result unveils that under inclined loading, equivalent plastic strain concentrates in the peripheral of caisson wall and the lower part of caisson. Soils inside the caisson are at elastic deformation state. In addition, the inclination angle of load has little influence on the relation between vertical load and settlement, but has evident impact on the relation between horizontal load and displacement. In the initial stage of deformation, the principal stress direction rotates apparently, and the rotation angle becomes larger with the increasing of load’s inclination angle. When vertical displacement ranges between 0.05D-0.10D, the principal stress direction reaches stable stage and stops rotating.