| dc.description.abstract | This research using Wyoming Bentonite (MX-80) and Yamagata Prefecture Bentonite (K-V1) in erosion and sedimentation experiments to understand changes in mass loss and radial expansion under various experimental factors.This was achieved through daily image recording and turbidity measurements. sedimentation experiments were conducted by adjusting angles to compare mass loss and radial expansion at different angles. Erosion experiments, on the other hand, compared variations in mass loss and radial expansion under different water chemistry conditions and incline angles, as influenced by the flow of water.
Results from the horizontal erosion study indicated that at higher cationic strengths, the diffuse double layer of the bentonite was affected, leading to a flocculation structure that slowed mass loss ; at a smaller crack width, the mass loss caused by erosion is also reduced. Moreover, K-V1 bentonite exhibited a faster development of secondary mineral rings compared to MX-80 bentonite. Consequently, K-V1 erosion was reduced due to the filtering layer formed by the secondary mineral rings, which inhibited subsequent mass loss.
The sedimentation experiment results revealed that with the change in the fracture incline angle, the mass loss caused by gravitational sedimentation increased. The interparticle distance during the saturation process of K-V1 bentonite was larger compared to that of MX-80, leading to a more dispersed structure.
Therefore, the mass loss under gravity was more significant in K-V1 bentonite.Findings from the 45° erosion experiment showed that in a high cationic strength 6mM environment, there was no noticeable mass loss due to the interaction of gravity and water shear forces. This highlights the significant influence of water chemistry on bentonite mass loss ; The results of the erosion test with an inclination angle of 60° show that in the environment of cation strength 1mM and 3mM, compared with the inclination angle of 45°, the mass loss tends to increase. | en_US |