摘要：Bentonite is a good candidate of buffer material for disposal repository of high-level radioactive
waste. Understanding groundwater behavior in bentonite buffer material is important in order to evaluate
the bentonite buffer performance and guarantee long-term safety. Elastic constants of the bentonite buffer
material are important parameters for the long-term safety. Water content in buffer material may have an
influence on its elastic properties. For this reason, the monitoring system of the water saturation level in
compacted bentonite is required. In this study, the ultrasonic velocity measurement method for evaluation of
water content in compacted bentonite was proposed. At first, the effect of a degree of saturation in
compacted bentonite on the longitudinal and shear wave velocities was investigated experimentally. In
addition, the elastic property, bulk modulus, in unsaturated compacted bentonite were evaluated by
ultrasonic velocities. As a result, it can be confirmed that ultrasonic velocities can evaluate a degree of
saturation and bulk modulus of compacted bentonite.
其他摘要：Bentonite is a good candidate of buffer material for disposal repository of high-level radioactive waste. Understanding groundwater behavior in bentonite buffer material is important in order to evaluate the bentonite buffer performance and guarantee long-term safety. Elastic constants of the bentonite buffer material are important parameters for the long-term safety. Water content in buffer material may have an influence on its elastic properties. For this reason, the monitoring system of the water saturation level in compacted bentonite is required. In this study, the ultrasonic velocity measurement method for evaluation of water content in compacted bentonite was proposed. At first, the effect of a degree of saturation in compacted bentonite on the longitudinal and shear wave velocities was investigated experimentally. In addition, the elastic property, bulk modulus, in unsaturated compacted bentonite were evaluated by ultrasonic velocities. As a result, it can be confirmed that ultrasonic velocities can evaluate a degree of saturation and bulk modulus of compacted bentonite.
