基于数字照相的砂土剪切变形模式的试验研究

利用自行研制的数字照相量测软件包Photolnfor和自行设计的大型剪切试验装置，在不同围压下，对砂土的剪切变形模式以及土体变形局部化的发生、发展和演变过程进行了全面观测．结果表明：砂土变形区域呈纺锤型，由多条曲线形大变形带和带间小变形区组成，不同围压下的剪切变形模式基本相近；土体最终形成的剪切带与初期发生的局部变形带并不完全重合；土体剪切变形可分为初期全域快速弹性变形、中期局部区域塑性变形与后期剪切带内集中塑性变形三个阶段．

Experimental Investigation of Shear Deformation Patterns in Sands Based on Digital Image Correlation

This paper presents a series of sandbox experiments of extensional deformation in Toyoura sands.The image analysis software package PhotoInfor,which was developed by the authors,was used to investigate the shear patterns and the evolution of the local deformation in sands under different confining pressures.The results show that: the deformation zone looks like fusiform,and can be di-vided into a number of large deformation bands and small deformation blocks in between the bands;more than one shear bands are not at the same location of the initial big deformation zone,in other words,the intense shear deformation zones migrate during shearing;and the soil deformation can be classified into three stages: initial stage of elastic deformation in the whole specimen,middle stage of elastic deformation in localized regions,and the final stage of plastic deformation in the final shear band.