察尔汗盐湖地区盐渍土微观结构及其力学与强度表现

为探明察尔汗盐湖区盐渍土的微观结构特征及其力学与强度表现,从盐湖区采集9组不同含盐量的盐渍土样品,对盐渍土进行电镜扫描、直接剪切试验和抗压强度试验,从微观结构上分析了盐渍土的力学与强度表现,提出了察尔汗盐湖区盐渍土颗粒骨架的连结形式。研究结果表明,不同含盐量的盐渍土微观结构形式不同,盐渍土颗粒骨架之间的连结有3种形式:1)点式接触、2)堆叠接触、3)盐晶体胶结;微观结构越密实,盐晶体胶结作用越强,盐渍土表现出越高力学与强度特性;盐晶体的胶结作用是影响盐溃土力学与强度特性的显著因素;无侧限抗压强度显著变化的含盐量拐点为45.74%。

The Micro-structure Characters of Saline Soil in Qarhan Salt Lake Area and Its Behaviors of Mechanics and Compressive Strength

In order to verify the micro-structure of saline soil in Qarhan Salt Lake area and its behaviors of mechanics and compressive strength,nine group saline soil samples with different salt content were collected from the Qarhan Salt Lake area,and the micro-structure of samples was scanned by electron microscope.Direct shear test and compression test were made accordingly.The behaviors of mechanics and compressive strength of saline soil were analyzed from the micro-structure.The paper also puts forward the skeleton connecting forms between particles of saline soil.The results show that：saline soil with different salt content has different micro-structure.The link of soil particles have three forms;1） point contact;2）stack;3） salt crystals cementation.The more dense the micro-structure is,the stronger the salt crystals cement,saline soils show higher mechanical and strength characteristics.Salt crystals cementation is the significant factor which affects the saline soil mechanics and strength characteristics.Unconfined compressive strength significantly changes when salinity reaches and exceeds 45.74%.