高放废物处置缓冲材料——膨润土压实成型性与抗压性研究

Compactibility and Compressive Behaviors of Bentonite——Buffer Material for High-level Radioactive Waste Disposal

采用模具,得到了膨润土立方和扇形压实块体,进而对其压实成型性和抗压性进行研究分析,建立了曲线拟合方程。结果显示,压实干密度、含水率等因素对压实成型性和抗压性影响较大,膨润土结合水与颗粒表面的相互作用起到关键作用。压实块含水率达到14%～15%范围内时出现最低压实压力,并且表现出较好的成型性;含水率在13%～15%之间时其无侧限抗压强度达到最大值,而后迅速下降,而且破坏方式也与含水率有关;压实块的压实压力随着压实干密度增加而呈现指数增加;压实干密度相近情况下,扇形压实块体的无侧限抗压强度稍大。

The moulds are used for compacting bentonite into cubic and fan-shaped blocks, the compactibility and the compressive behaviors are analysed, the curves fitting equations are established. The results show that the compactibility and the compressive behaviors are affected greatly by compacting dry density, moisture content and other factors, the interactions between bound water of bentonite and its particle surface play a key role. A minimum compacting pressure will appear when the water content of compacted bentonite block reaches 14%-15%, and also exhibits a better compactibility; The unconfined compressive strength achieves maximum when the bentonite blocks with 13%-15% water content and then decreases rapidly, furthermore,the failure mode relates to the water content; The compacting pressure of the compacted bentonite blocks increases exponentially with the compacting dry density;it is found that the unconfined compressive strength of fan-shaped block with similar compacting dry density is slightly larger.