砂土中螺旋桩在斜拉荷载作用下的承载性能

Bearing performance of helical piles in sand under oblique tensile load

为研究斜拉荷载倾斜角度和叶片埋深对螺旋桩极限承载力的影响,基于ABAQUS软件构建了砂土中螺旋桩的有限元模型,通过螺旋桩水平承载机理砂箱试验与竖向拉拔试验数据,对模型的准确性和可行性进行验证。设置4组不同叶片埋深的螺旋桩模型,分别施加不同角度的斜拉荷载,探讨了砂土地基中螺旋桩的承载性能与斜拉角度、叶片埋深的相关性。结果表明:砂土中螺旋桩的极限承载力随着斜拉角度的增大不断减小;当斜拉角度小于30°时,螺旋桩极限承载力与斜拉角度的关系曲线近似呈线性;螺旋桩极限承载力存在一个临界埋深比,当埋深比大于等于4时,承载力不随埋深比的增大而变化。推导了深埋状态下螺旋桩受斜拉荷载作用的极限承载力公式,经验证该公式能较好反映螺旋桩极限承载力随斜拉角度增大而逐渐下降的规律。

In order to study the correlation between bearing capacity of helical piles in sand foundation and oblique tensile angle and burial depth,the finite element model of helical piles in sand is established by ABAQUS.The numerical simulation results and test results of helical piles under vertical and horizontal pull-out are compared to verify the accuracy and feasibility of the numerical model.Considering the influence of oblique tensile angle and burial depth on the ultimate bearing capacity of helical piles,four groups of helical pile models with different burial depths,are set up and different oblique tensile angles are applied respectively.The results suggest that the ultimate bearing capacity of helical piles in sand decreases when the oblique tensile angle increases.When the oblique tensile angle is less than 30°,the relationship curve between the ultimate bearing capacity and the oblique tensile angle is approximately linear.There is a critical burial depth ratio for the ultimate bearing capacity of helical piles.When the burial depth ratio is not less than 4,it does not change with the increase of burial depth ratio.Meanwhile,the ultimate bearing capacity formula of deeply buried helical piles under oblique tensile load is derived.Through verification,the formula can better reflect the rule that the ultimate bearing capacity of helical piles decreases gradually with the increase of oblique tensile angle.