膨润土-砂混合料膨胀特性的试验研究

Experimental Research on Expansive Properties of Bentonite-sand Mixture

利用自制的岩土三向膨胀力测量仪,采用不同干密度、掺砂率对膨润土-砂混合料膨胀特性进行试验。研究结果表明:膨润土-砂混合料的膨胀力随掺砂率的增加而减小,随干密度的增大而增加;在已知掺砂率下,当干密度大于1.7 g/cm3以后,膨胀力随干密度增加明显;通过砂骨架孔隙比,可以确定不同掺砂率下混合料砂骨架形成时所对应的起偏应力,进而可以计算得到合理的临界掺砂率。

The self-made geotechnical three-way expansion force measuring instrument was used to study expansive properties of bentonite-sand mixture with different dry densities and sanding rates. Experimental results show that the expansion force of the bentonite-sand mixture decreases with the increase of sanding rate while increases with the increase of dry density. Under the known sanding rate, when the dry density is greater than 1.7 g,/cm3, the expansion force increases with dry density significantly. Through the sand skeleton void ratio, different sanding rates can be determined under the mixture of sand skeleton formed by deviatoric stress, so reasonable critical sanding rate can be calculated.