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以数字图像相关(DIC)技术为基础,开发出适合岩土实验模型变形量测分析的新技术,并将该技术应用于垂直荷载下桩周土体位移场及其破坏模式的研究。试验中,直接用数码相机在试验各阶段拍摄照片,对照片序列进行图像相关分析,即可得出桩基模型试验的变形场分布。试验结果表明:利用编制的DIC程序分析桩周土体位移场是可行的;垂直荷载下单桩桩周土体位移场可分为桩侧土体变形区及桩端土体竖向变形区两个部分。随着离开桩轴线距离的增大,桩侧土体位移急剧减少,其影响范围为(4～5)b(b为桩的边长);桩端土体受扩张压力的作用,沿径向向外扩张,呈孔穴扩张现象。从桩周土体的位移场的发展过程来看,单桩呈“梨形”破坏,与Meyerhof所提出的桩周土破坏模式相似。
Based on Digital Image Correlation (DIC) technique, a new technique suitable for deformation measurement of geotechnical test model was developed. The technique was applied to study the displacement field and the failure mode of soils under vertical load. In the experiment, the digital camera was used to take pictures of each stage of the experiment, and the image sequence analysis was carried out to obtain the deformation field distribution of the pile foundation model test. The experimental results show that it is feasible to analyze the displacement field of the pile around the pile by using the DIC program compiled. The displacement field of the soil around the pile under vertical load can be divided into the soil deformation zone at the pile side and the vertical deformation zone at the pile tip Part. With the increase of the distance from the pile axis, the soil mass displacement on pile side decreases sharply, and its influence range is (4 ~ 5) b (b is the side length of the pile). The soil under pile tip is affected by the expansion pressure, Expansion of the hole was dilated phenomenon. From the development process of the soil displacement field, the single pile is “pear shaped”, which is similar to the damage model of the soil around the pile proposed by Meyerhof.