Thermo-hydro-mechanical characterisation of a bentonite-based buffer material by laboratory tests and numerical back analyses

This paper presents some laboratory tests performed on the bentonite used a s buffer material in the engineered barrier experiment in Kamaishi mine in Japan and a collective effort of four research groups to characterise the c oupled thermo-hydro-mechanical behaviour of the bentonite by comparing nume rical calculations with the laboratory test results. Each research group us ed finite element programs with constitutive models capable to simulate bot h liquid and vapour flux of water, heat transfer, volume change, swelling p ressure and mechanical deformation. Numerical calibrations were performed a gainst results obtained from three types of laboratory tests: water infiltr ation tests, thermal gradient tests and swelling pressure tests. Parameter values, which could not be directly measured in laboratory tests, were obta ined with these calculations. (C) 2001 Elsevier Science Ltd. All rights res erved.