Study On Transparent Synthetic Sand And Its Triaxial Test

Conventional method for measuring the specimen deformation can't exhibit internal dynamics process, while modern digital imaging techniques are commonly restricted on the measurement of macroscopic deformation and boundary. Acquirement of specimen's internal dynamic strain information is still an open issue. The usage of transparent synthetic soil overcomes this difficulty efficiently.Transparent synthetic sands are commonly made from amorphous silica gel. But the large difference of intrinsic structure between silica gel grain and natural sand can dramatically affect their properties. The absence of internal micro-channel in transparent fusion quartz sand makes it be similar with natural soil, so it is chosen in the present work. Calcium bromide solution with proper concentration substitutes for the pore fluids. In the experiment of specimen deformation, the material properties of fusion quartz sand and calcium bromide solution are similar with natural soil and pure water, respectively. Experiment results show that saturated sand specimen put forward in this work has better transparence and can be used in digital imaging techniques for the measurement of internal deformation.Triaxial tests were carried out on the transparent synthetic sand mentioned above to systematically explore and compare its mechanical behavior with natural soil under different conditions. Results indicate that transparent synthetic sand and natural sand have similar stress-strain behavior. With the increase of confining stress, the difference of transparent synthetic sand's curves of axial strain vs. bulk strain (or axial strain vs. radial strain) and natural sand's curves with the same relative density become larger, while the curves of axial strain vs. deviator stress deviate a little. So experiment results of transparent synthetic sand are good representations of natural soil except situation of large confining stress if specimen's strength is concerned. On the other hand, confining stress plays an important role when specimen's strain is concerned.