为探明竖向荷载作用下螺牙高度对螺纹桩承载特性及桩周土体的影响，通过室内半面模型桩试验，结合数字图像相关技术（DIC），研究了不同螺牙高度、不同荷载条件对桩身承载性能、桩周土体破坏特征、桩周土体位移场的影响。采用ABAQUS数值模拟方法对模型试验的结果进行验证，并扩展了螺牙高度的取值范围，分析螺纹桩桩身极限承载力与材料利用率、桩周土体应力场分布随螺牙高度变化的规律。结果表明：增加螺牙高度能提升桩身承载力，增大桩周土体位移影响范围，延缓桩侧土体剪切破坏的发展；随着桩身沉降量增加，桩顶荷载以桩侧阻力承受为主，逐渐演变为以桩端阻力承受为主；螺牙高度的增加虽然能提升桩身极限承载力，但桩身材料利用率存在峰值。

In order to find out the influence of screw height on bearing characteristics of threaded pile and soil around the pile under vertical loading, this paper studied the influence of different screw heights on the bearing performance of pile, soil failure characteristics around the pile and soil displacement field around the pile through laboratory half-surface model pile test combined with digital image correlation (DIC) technique. The ABAQUS numerical simulation method was used to validate the results of the model test, and the range of screw height values was extended. The pattern of the ultimate bearing capacity and material utilization rate of threaded pile as well as the distribution of soil stress field around the pile were analyzed. The results show that the utilization bearing capacity of pile is increased, the influential zone of the soil displacement around the pile gradually increased and the development of shear failure of soil around the pile can be delayed with increase of the screw height. As the settlement of the pile body increases, the loading on the pile top gradually evolves from being borne by the pile side resistance to borne by the pile end resistance. Although increasing the screw height can enhance the ultimate bearing capacity of pile, there is a peak in the material utilization rate of the pile.

TU473.1

国家自然科学基金（52008185）