Tsukasa NISHI
RIMS Experiment for Visualizing Motion of Soil Particles and Seepage Flow
Satoru OHTSUKA Yutaka FUKUMOTO
Preventing from natural disasters is an important issue in the civil engineering.In recent years it has occurred many liquefaction phenomena.The interior of the ground cannot be directly observed.We cannot know the mechanism in detail.As a way to observe the inside of the ground, there are MRI technique and X-ray CT technique.but they are relatively expensive.In this study, in order to reproduce the soil particles, we employ glass beads in the acrylic container.By using the refractive index matching visualization techniques (RIMS), two-dimensionally directly observation of inside of the ground is possible.However, the RIMS technique has a lot of problems.For example, there is a problem in which the particles are deformed. In addition, the RIMS depends on the environment such as humidity and tempresure.From now on, the RIMS is further considered to increase the demand.This study analyzes the seepage flow velocity by PIV measurement and the behavior of the soil particles by the motion analysis of time series. This study is the basic experiment of the first stage for the purpose.From this experiment, a combination of soda glass and silicone oil, it was possible to obtain arbitrary cross section information up to approximately the depth 30mm from surface of the container.
PIV analysis of the seepage flow velocity inside soil particles in a cross section on the laser sheet is possible.In addition, it was found that the time series motion analysis of soil particles is possible by using the RIMS.However, the seepage flow velocity inside soil particles, time series analysis of soil particles could not perform photographing at the same magnification.Further, it is necessary to select close values for density and viscosity.And, I would like to perform the RIMS in a device for measuring the seepage failure.Then, the analysis of the seepage flow velocity in the pore.Based on the results obtained by the analysis of the RIMS experiment, we plan to execute the numerical simulation.By doing so, it is believed that we can clearly grasp the mechanism of the seepage failure and internal erosion.
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