Abstract: By using the image analysis software package PhotoInfor, which is based on the digital photogrammetry for deformation measurement technology, we analyze the generation, development and evolution process of displacement in sands during each load level of confined compression tests. The results can show that, the axisymmetric displacement fields of sands are similar like parabola, displacement’s equivalence lines are axisymmetric-distributed, and the largest increment of displacement always occurs at the bottom’s center of the up porous stone. With the monotonic loading, displacement increment mainly concentrates in the vicinity of localized deformation zones, with an obvious trend of continuous extention and transfixion. The displacement at the top and the middle position keeps linearly increasing with the overall compression deformation. However, the displacement of the testing point at the top is always larger than the middle one. Such phenomenon will be more obvious during the metaphase and the anaphase of the tests. Compared with the displacement fields of silty clay sample, the granular soil will represent a conspicuously different rule for the stress transferring route, deformation patterns and loading impact scope. The research can put forward a new concept to study the stress distribution rules under foundations, as well as to study the quantitative model of sands’ microstructure by macro experimental phenomenon.

Key words: granular soil, digital image analysis, compression deformation, displacement measurement