论文部分内容阅读
为探究高放核废物深地质处置缓冲材料的长期稳定性,以内蒙古高庙子(GMZ)天然钠基膨润土为研究对象,揭示了γ辐照老化作用对高压实天然钠基膨润土样品力学强度和变形特性的影响。采用钴源在室温下对该膨润土进行不同累积剂量的辐照作用,分析了辐照前、后膨润土的矿物成分变化,并开展了三轴剪切以及膨胀变形试验。结果表明:γ辐照老化作用引起膨润土部分矿物成分的变化,蒙脱石微观结构稳定性降低并转化为更稳定的硅酸盐和硅铝酸盐矿物;膨润土经过辐照作用后剪切强度有所增长且随辐照剂量增大,矿物成分发生了变化,同等围压下膨润土的剪切峰值强度逐渐提高;随着围压的增大,强度增长的幅度逐渐变缓,辐照剂量对强度的影响减弱,表明围压对膨润土强度的增长有一定的抑制作用;由于辐照后蒙脱石的含量减少,膨润土的膨胀变形性能相应减弱,即膨胀力、自由膨胀应变、有荷膨胀应变等指标降低。
In order to explore the long-term stability of high-concentration nuclear waste deep geological disposal cushioning material, natural sodium bentonite of GMZ in Inner Mongolia was studied to reveal the effect of γ-irradiation aging on the mechanical strength And deformation characteristics. Cobalt sources were used to irradiate the bentonite at various cumulative doses at room temperature. The changes of mineral composition of bentonite before and after irradiation were analyzed. Triaxial shear and deformation tests were carried out. The results show that the aging of γ radiation causes the change of some mineral components of bentonite, and the stability of montmorillonite microstructure decreases and transforms to more stable silicate and aluminosilicate minerals. The shear strength of bentonite after irradiation With the increase of irradiation dose, the mineral composition changed. The shear peak strength of bentonite gradually increased under the same confining pressure. With the increase of confining pressure, the amplitude of strength growth gradually became slower. The effect of irradiation dose on the strength The results show that the confining pressure has certain inhibitory effect on the strength of bentonite. Due to the decrease of the content of montmorillonite after irradiation, the deformation and deformability of bentonite is correspondingly weakened, ie, expansion force, free expansion strain and load expansion strain Indicators lower.