砂土中吸力式沉箱基础的最佳荷载作用点位置模型试验研究

Model tests on optimal load attachment point of suction caisson foundation in sands

通过一系列模型试验研究了倾斜荷载作用下吸力式沉箱基础的最佳作用点位置，试验中考虑了荷载作用点、荷载作用角度和长径比3个重要因素。基于模型试验得到的荷载一位移曲线，采用合适的破坏标准确定了各工况下吸力式沉箱基础的抗拔承载力，根据承载力的变化规律分析确定了吸力式沉箱基础的最佳作用点位置。结果表明，荷载作用角度对吸力式沉箱基础承载力的影响显著，当荷载水平作用于基础时，其承载力最大。荷载作用点位置对吸力式沉箱基础承载力的影响取决于荷载作用角度的大小，当荷载作用角度较小时，荷载作用点位置的影响显著，且最佳作用点位置位于沉箱高度的2／3-3／4处；当荷载作用角度较大时，荷载作用点位置的影响很小，可以忽略。结合荷载与吸力式沉箱基础的转角关系，分析了荷载水平作用于最佳作用点下吸力式沉箱基础的破坏模式。

A series of model tests are conducted to study the optimal load attachment point for the suction caissons embedded in sands under inclined loading. The factors of load attachment point, loading angle and length to diameter ratio are considered. Based on the load-displacement curves obtained from model tests, the uplift bearing capacity of suction caisson foundations are determined by a suitable failure criterion. Then the optimal load attachment point is obtained by the analysis of the variation ofuplift bearing capacity of suction caisson foundations. It is found that the loading angle has a significant role in the uplift berating capacity of suction caisson foundations; and the maximum uplift bearing capacity will occur when the loading is in the horizontal direction. The effect of load attachment point on the uplift bearing capacity of suction caisson foundations depends on the magnitude of loading angle. The load attachment point has great effect on the uplift bearing capacity of suction caisson foundations when the loading angle is relatively small. The attachment point associated with the maximum uplift bearing capacity is located at approximately 2/3-3/4 of the suction caisson length from the top; otherwise, it can be neglected. Based on the relationship between load and rotation degree of suction caisson, the failure model of suction caisson foundation under horizontal loading acted on the optimal load attachment point is analyzed.