| dc.description.abstract | The low-level radioactive waste final disposal adopts the design concept of multiple barriers internationally, and uses layers of disposal facilities to isolate radioactive materials away from the biosphere. Buffer material play a very important role in multiple barriers system, and must have low hydraulic conductivity and appropriate swelling pressure. When the disposal site is enabled, the future may be subject to groundwater intrusion, buffer material may be affected by changes in the original expected behavior characteristic.
This study is mainly two parts. The first part uses MX-80 bentonite and
K-V1 bentonite at different dry density to conduct direct shear test and one dimensional compression test to simulate the effect of initial load at the disposal site. The second part conducts swelling pressure, hydraulic conductivity test, saturated strain/stress controlled direct shear test and one dimensional compression test to simulate the situation of the disposal site at saturation, and finally uses finite element software ABAQUS for analysis and simulation.
The results of the study show that (1) MX-80 bentonite is better in terms of swelling pressure, because the montmorillonite content of MX-80 bentonite is higher than that of K-V1 bentonite. (2) MX-80 bentonite in the direct shear test has high dry density, high normal stress and saturation, it has better shear resistance than K-V1 bentonite. (3) Stress control direct shear shows that the greater the applied shear stress, the faster the occurrence of creep will be accelerated. (4) The one dimensional compression test shows that the greater the normal stress, the greater the strain of bentonite and the earlier the creep time. | en_US |