HR: 0800h
AN: H21E-1065    [Abstracts]
TI: Simultaneous Determination of the Hydraulic Conductivity and Specific Storage of A Test Specimen From Laboratory Permeability Tests
AU: * Zhang, M
EM: m.zhang@aist.go.jp
AF: Research Center for Deep Geological Environments, National Institute of Advanced Industrial Science and Technology, Central 7, 1-1-1, Higashi, Tsukuba, 305-8567 Japan
AU: Takeda, M
EM: mikio-takeda@aist.go.jp
AF: Research Center for Deep Geological Environments, National Institute of Advanced Industrial Science and Technology, Central 7, 1-1-1, Higashi, Tsukuba, 305-8567 Japan
AU: Aung, T T
EM: aung-than@aist.go.jp
AF: Research Center for Deep Geological Environments, National Institute of Advanced Industrial Science and Technology, Central 7, 1-1-1, Higashi, Tsukuba, 305-8567 Japan
AB: Laboratory testing of representative specimens has been a very useful and widely adopted approach for characterizing the physical properties of geological materials. One of the particular challenges in geotechnical and/or geoenvironmental laboratory testing is the accurate determination of the hydraulic properties of low-permeability geological materials such as clays, intact rocks and the mixtures of sand and clay. These materials are now being studied in increasing detail because of their importance in retarding the transport of hazardous wastes, including radioactive nuclear wastes. Although laboratory permeability tests are thought to be well-established, most methods can obtain only the value of hydraulic conductivity and the specific storage, another important parameter related to the transient flow, is disregarded in the analyses. In addition, conventional test methods require relatively-long times for testing low-permeability geological materials. In this study, we present a set of rigorous solutions to three kinds of laboratory permeability tests: the constant-head, rising tail-water elevation; the falling-head, constant tail-water elevation; and the falling-head, rising tail-water elevation. A new system that can implement any of these three test methods is also introduced. This new system permits automated recording of the heads in up and down streams, eliminating the effects of temperature variation and evaporation on flow rate measurements. The applicabilities and advantages of these improved technologies are demonstrated using a series of experimental data derived from a compacted mixture of sand and clay. The results indicated that using the rigorous solutions to analyze unsteady or transient-phase data obtained from individual permeability tests permits the test durations to be shorted without sacrificing accuracy in estimating both the hydraulic conductivity and the specific storage of a test specimen.
DE: 5114 Permeability and porosity
DE: 1800 HYDROLOGY
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting