Integrated Shear and Flow Parameter Measurement

Abstract

Studies on the variation of permeability and the specific storage of bentonite-sand mixtures with shear deformations that may be caused by earthquakes and/or other geological events are of fundamental importance for long-term safety assessments of radioactive nuclear waste disposal facilities. This paper presents a recently developed and improved method for integrated shear and flow parameter measurements on a mixture of Kunigeru V1 Bentonite and D-Sand. This material will be used in low-level radioactive nuclear waste disposal facilities in Japan. The results of this study show that: (1) temperature control is important for measuring hydraulic parameters of low-permeability materials with the flow pump method; (2) shear strains up to about 3% did not significantly influence either the permeability or the specific storage of the bentonite-sand mixture; and (3) permeability and specific storage values interpreted from different time intervals during the transient rise and transient decay phases of the flow pump permeability tests were almost the same, which suggests that the reliability of both the experimental results and the newly derived theoretical analysis used to interpret the hydraulic parameters.