Abstract: In the conventional visualization model test, the displacement and deformation in the two-dimensional observation window can be observed, but the out-of-plane displacement of the three-dimensional(3D) problem and the 3D deformation field cannot be obtained. Therefore, based on the transparent soil model test, a set of automatic tomographic scanning test device is independently developed in this study. The synchronous motion of the camera with the laser device is controlled by a high-precision electric linear platform to obtain a series of two-dimensional images. The improved image deformation measurement method is used for image post-processing. On this basis, a corresponding 3D reconstruction volume rendering program is coded to construct the 3D displacement field after deformation. In order to verify the feasibility of the visualization measurement system of spatial deformation, static pressure tests of square foundation and circular foundation in transparent soil are carried out. The test results show that the contour of the 3D vertical displacement and horizontal displacement after reconstruction are consistent with the theoretical prediction results and with those previously presented in the literature. The 3D vector displacement field can directly show the movement of soil mass at different positions, which eliminate that the 2D observation technique cannot reflect the out-of-plane displacement. This study not only further reveals the spatial deformation problem in static pressure test, but also provides a feasible method for realizing the observation of spatial deformation in the physical model test.

Key words: transparent soil, tomographic scanning, 3D reconstruction, 3D displacement field, static pressure tests