Transparent Sand Experimental Method for Geotechnical Physical Modeling Using Digital Imaging of Particle Image Velocimetry

By means of the technology of particle image velocimetry (PIV), the physical modelings, using transparent sand and natural sand, were set up to simulate the shallow foundation, respectively. The transparent soil is composed of fused quartz and correspondingly refractive index-matched flammable liquid. The flammable liquid is blended by two white mineral oils, Krystol40 and Puretol7. Transparent sand model was projected by a laser light sheet; meanwhile, the digital images of soil deformations caused by shallow foundation were captured. The PIV was employed to obtain the generated displacement fields from the digital images. The experimental results indicate that the deformation trends in transparent sand model are consistent with that in natural Ottawa sand model; however, the influential region is expanded by about 1.5 times, and the zone and magnitude of down-drag subsidence are extremely enlarged in transparent soil model, compared with those in Ottawa sand model. The verification of test results shows that the shallow strain path method is not suitable for the small-scale transparent sand and natural sand models.