中文摘要：

对土与结构界面细观试验研究现状进行归纳总结,并利用新研制的大型可视化界面剪切仪,进行干 砂-钢板接触面的直剪试验,试验过程中结合数字图像相关测量技术（D IC ）从细观角度测量紧邻接触面及其上 部砂土颗粒的剪应变和位移变化.由试验可知：剪切过程中砂颗粒在结构面的带动下产生平移、挤压、错动和 转动,剪切带最终稳定厚度约为（2-5）D;颗粒的细观运动影响颗粒接触,也是宏观剪胀的因素之一.

英文摘要：

The present situation of the research on soil-structure interface is summarized at f irs t ,and then the direct shear test of dry sand-steel plate contact surface is carried out by u-sing a new large-scale visual interface shear instrument. In the experiment, the shear strain and displacement of the adjacent contact surface and the upper sand particles are measured by the digital image correlation measurement （DIC） technique. It shows that the sand particles are driven by the structural plane to produce translation, extrusion, dislocation and rotation during the shearing process; the shear band thickness is about （2-5）D50 ; particle mesoscop-ic movement one of the factors of macro-dilatation,has influence on particle contact.