成桩挤土效应实验验证

Test Validation of Hole Expansion Effect During Penetration of Pile

利用数字图像技术,再现了沉桩挤土效应。在模型桩贯入过程中,采用高像素的数字相机连续摄取桩及桩周土体变形的灰度图像,对所采集的数字图像进行相关运算,求出全场土体位移矢量。试验结果表明桩端挤土类似于球形扩张,桩端土在挤压力作用下向外扩散。本法操作简便,对环境要求不高,可以应用于研究土体变形机理的试验研究。

The hole expansion effect of soil is studied by means of digital image technique. During the penetration of the model pile, the grayscale images of soil and the pile are taken by the digital camera of high pixel. The images are disposed by digital cross - correlation method, and then the displacement vectors of the soil can be worked out.. The findings indicate the driven compaction effect is similar to the spherical cavity expansion, and the soil is displaced out by the pressure. The method is easy to handle in the environment which is not highly demanding and can be applied in the test study on the deformation mechanism of soils.