| dc.description.abstract | After Tohoku Earthquake, huge amount of disaster waste including radioactive substances were released to the environment due to the accident of Fukushima No.1 nuclear power plant. To deal with these radioactive substances, Japanese government hope to build an offshore waste disposal facility for storing the waste materials. Different from normal disposal facility, this disposed waste is radioactive, therefore, more regulations were formulated by some researchers. In the part of sealing material, the radioactive substances may penetrated to outside and polluted the environmental. Avoiding this condition and confirm that the substances would become safe (half-life) is very important. By easy calculation, the coefficient of permeability of sealing material is 5×〖10〗^(-10) m/s. And find that a clay mixture, clay with bentonite, can achieve the target value. However, if some nature disaster happen, such as tsunami of earthquake, huge shearing deformation would force on the material and the permeability may change. Therefore, knowing the changing play an important role on this research.
In order to test the changing of coefficient of permeability, this research developed a new testing method called Hollow Cylinder Torsional Permeability Test (HCTPT). This test can give some torsion to generate shear strain and test the permeability. In this way, the more real condition can be simulated. HCTPT also begin a new method of testing horizontal coefficient of permeability. In mixing the bentonite into clay can decrease the coefficient of permeability. Also, a new testing method to measure the horizontal coefficient of permeability by hollow cylinder torsional shear test is developed. The measured horizontal coefficients of permeability kh were in the range of 1.5~2.0 times that of vertical coefficient of permeability, as the measured value of kh did not increase by being sheared horizontally. It was found that there is no considerable increase of permeability due to the change of shear deformation. | en_US |