SHIOHARA　YUKI

Direct measurement of changes in osmotic flow by differences in soil skeleton structure using transparent soil

OHTSUKA Satoru

 Internal erosion phenomenon is a cause of damage to civil engineering structures. However, there are many points that have not yet been elucidated.So, in this research, we aim to establish an experimental method to visualize internal seepage flow which cannot be directly seen by using Refractive Index Matching Scanning (RIMS) technology, and to grasp the characteristics of osmotic flow through a simple model experiment . Although MRI, X-ray CT, etc. exist as a method of observing the inside of the ground, they are relatively expensive and cannot be easily experimented. In addition, there are researches to understand the characteristics of the seepage flow according to the state of the fluid by the Reynolds number, but there is no consistent and wide-ranging study observed from the laminar flow state to the turbulent state, need more consideration. Therefore, we conducted an experiment using RIMS technology to visualize the internal seepage flow that cannot be seen directly, with the aim of understanding the characteristics of the seepage flow due to differences in the structure of the soil skeleton.The experimental results show that even if a particle distribution of 3 mm to 10 mm exists, the experimental method can directly observe the permeation flow in the gap. The tendency of the distribution of the infiltration velocity to change depending on the size of the Reynolds number was also confirmed when the soil structure changed. In addition, when comparing the case of different soil skeleton structures in the same range of Reynolds numbers, differences were found in the frequency of the mode and the magnitude of the maximum value of the velocity distribution. Based on the results obtained in this research we will continue to improve accuracy in both numerical analysis and experiment.