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Nishimura, Mayuka; Tanai, Kenji; Takaji, Kazuhiko*; Hirai, Takashi*; Shiratake, Toshikazu*
JAEA-Research 2006-036, 82 Pages, 2006/06
JAEA-Research-2006-036.pdf:4.09MB
In order to evaluate the long term mechanical behavior of the Enginnered Barrier System (EBS), it is essential to set suitable parameters of constitutive models of the buffer material. In this report, the parameters of the Sekiguchi-Ohta model and the Adachi-Oka model are examined. The results are as follows; it is impossible to set the sole parameter which can evaluate both the deformation and the stress of the buffer material. But when selecting a suitable parameter for the object of evaluation, the mechanical behavior of buffer material can be approximately described. On the other hand, the range of the secondary consolidation coefficient of the bentonite ore is estimated to corroborate to the viscous parameter of the buffer material, using a natural analogue study. Finally, the mechanical behavior of the buffer material is analyzed using these parameters, and the maximum amount of settling of the overpack is estimated.
Takaji, Kazuhiko*; Shigeno, Yoshimasa*; Shimogochi, Takafumi*; Hirai, Takashi*; Shiratake, Toshikazu*
JNC TJ8440 2004-011, 200 Pages, 2005/02
JNC-TJ8440-2004-011.pdf:5.05MB
On the R&D of the high-level radioactive waste repository, it is essential that Engineered Barrier System (EBS) is stable mechanically over along period of time for maintaining each ability required to EBS. After closing the repository, the various external forces will be affected to buffer intricately for along period of time. So, to make clear the mechanical deformation behavior of buffer against the external force is important, because of carrying out safety assessment of EBS accurately. In this report, several sets of parameters are chosen for the previously selected two constitutive models, Sekiguchi-Ohta model and Adachi-Oka model, and the element tests and mock-up tests are simulated using these parameters. Through the simulation, applicability of the constitutive models and parameters is examined. Moreover, simulation analyses of EBS using these parameters were carried out, and mechanical behavior is evaluated over a long period of time. Analysis estimated the amount of settlement of the over pack, the stress state of buffer material, the reaction force to a base rock, etc., and the result that EBS is mechanically stable over a long period of time was obtained. Next, in order to prove analyses results a side, literature survey was conducted about geological age, the dynamics history of a Smectite layer. The outline plan was drawn up about the natural analogue verification method and preliminary examination was performed about the applicability of
Takaji, Kazuhiko*; Shigeno, Yoshimasa*; Shimogochi, Takafumi*; Shiratake, Toshikazu*; Tamura, Hirokuni*
JNC TJ8440 2003-007, 218 Pages, 2004/02
JNC-TJ8440-2003-007.pdf:4.43MB
On the R. and D. of the high-level radioactive waste repository, it is essential that Engineered Barrier System (EBS) is stable mechanically over a long period of time for maintaining each ability required to EBS. After closing the repository, the various external forces will be affected to buffer intricately for a long period of time. So, to make clear the mechanical deformation behavior of buffer against the external force is important, because of carrying out safety assessment of EBS accurately.In this report, several sets of parameters are chosen for the previously selected two constitutive models, Sekiguchi-Ohta model and Adachi-Oka model, and the element tests and mock-up tests are simulated using these parameters. Through the simulation, applicability of the constitutive models and parameters is examined.Moreover, simulation analyses of EBS using these parameters were carried out, and mechanical behavior is evaluated over a long period of time. Analysis estimated the amount of settlement of the over pack, the stress state of buffer material, the reaction force to a base rock, etc., and the result that EBS is mechanically stable over a long period of time was obtained. Next, in order to prove analyses results a side, literature survey was conducted about geological age , the dynamics history of a Smectite layer.The outline plan was drawn up about the natural analogue verification method and preliminary examination was performed about the applicability of "Freezing Sampling".