桩与土接触面的力学特性是桩-土共同作用研究中的一个重要课题。利用基于数字图像的非接触光学测量方法,通过室内模型试验,对密实砂土中桩-土接触面上荷载传递特性、剪切位移场及剪应变场分布规律进行研究。结果表明:密砂中单桩桩侧摩阻力与沉降关系呈软化型,桩侧摩阻力达到极限值所需桩身沉降约为桩横截面边长的3%。桩周土体剪切滑动区发生在有限范围的土体中,最大剪应变首先出现在桩顶及桩底附近土体中,而后向桩身中部发展,在极限荷载条件下,最大剪应变沿桩身呈“两头大中间小”的分布形式。试验结果为合理建立桩-土接触面模型和相关数值计算提供有益的参考。 The mechanical properties of pile-soil interface is an important issue in the research of pile-soil interaction. Based on the non-contact optical measurement method based on digital image and the indoor model test, the load-transfer characteristics, shear displacement field and shear strain field distribution on the soil-pile contact surface are studied. The results show that the relationship between the lateral friction and the settlement of the single pile in sand is softened, and the settlement of the pile required for the frictional resistance of the pile is about 3% of the lateral length of the pile. The soil shear sliding zone around the pile occurs in a limited range of soil. The maximum shear strain first appears in the soil near the top and the bottom of the pile, and then develops toward the middle of the pile. Under the ultimate load, the maximum shear strain Pile was “two big middle small ” distribution. The test results provide useful references for the reasonable establishment of the pile-soil contact surface model and the related numerical calculation.