UI Tomoaki

Study on Direct Measurement of Seepage Flow Inside the Soil Skeleton by RIMS

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, a model experiment was conducted with the purpose of observing the behavior of the seepage flow inside the soil skeleton when the state of the fluid was changed from the laminar flow state to the turbulent state.
 Experimental results showed that the seepage flow could be observed from the laminar flow state to the turbulent state, numerical analysis and verifiable data could be obtained, and with the change in the Reynolds number, it was experimentally confirmed that the distribution tendency of the flow velocity of flow rate changes. Since it was possible to establish a seepage flow measurement method in this research, it will be possible to proceed to the measurement experiment of both soil particles and permeate flow in the future in application. In addition, at the present time, numerical analysis can only analyze under laminar flow conditions, and turbulence model needs to be incorporated in order to analyze up to the turbulent state. Based on the results obtained in this research we will continue to improve accuracy in both numerical analysis and experiment.