固化盐渍土经干湿循环后力学性能变化的机理

Mechanism of Alteration in Mechanical Property of Solidified Saline Soil Affected by Wetting-Drying Cycles

利用自主开发的YZS固化剂对青海格尔木地区的一种原生粘质盐渍土进行固化,研究了该固化土体在干湿循环后的力学性能变化规律.用环境扫描电镜和压汞试验观察了固化土试件内核和外围部分的微观结构,并分析了试件的破坏机理.结果表明:经过干湿循环作用后,固化盐渍土的无侧限抗压强度提高而劈裂抗拉强度降低,其原因是干湿循环作用造成了固化土体试件的核心部分结构增强而外围部分结构削弱.因此,无侧限抗压强度指标不能恰当地反映干湿循环对于固化盐渍土的破坏作用,而劈裂抗拉强度则可以体现干湿循环的破坏作用.

The YZS soil stabilizer developed by ourselves was used for solidification of a natural saline soil in Ge Ermu, Qinghai Province. Alteration in mechanical property of solidified soil after wetting-drying cycles was investigated. The microstructure of both core and outer part of the damaged solidified soil body was characterized by means of ESEM and mercury intrusion method. The failure mechanism of solidified soil in compression or split test was discussed. The results show that the unconfined compressive strength of the soil body increases and its splitting strength decreases after wetting-drying cycles, which is resulted from the fact that the core of soil body is intensified and its outer part is weakened by wetting-drying process. Therefore, the compressive strength can hardly reveal the damaging effect from wetting-drying process on solidified soil body, but conversely splitting strength can do it.