天然盐渍土工程特性对比分析

为了深入研究西北地区天然粗、细颗粒盐渍土的工程特性,探讨不同盐渍土的颗粒组成对盐渍土地区道路病害防治措施方法选择的影响,文中对采自甘肃及新疆的典型天然粗粒盐渍土和细粒盐渍土分别进行了室内基本工程性质试验和大尺寸多次冻融循环盐胀模型试验,并对经过多次冻融循环后的天然盐渍土进行电镜扫描及分析对比。试验结果表明,粗粒盐渍土在降温阶段土体产生盐胀后亦会出现下陷,最终土体溶陷量大于盐胀量,冻融循环次数的增加会导致粗粒盐渍土大颗粒骨架破坏塌陷;细粒盐渍土具有较好的盐胀累加性,随着冻融循环次数的增加在自然升温阶段盐胀累加性不再明显,盐胀率与冻融循环周期的关系符合二次抛物线变化规律;由于粗、细粒盐渍土在冻融后微观结构组成上存在差别,在选择道路处治措施时应该采用不同的方法。

Comparison analysis on engineering properties of crude saline soil

In order to research the salt expansion laws of crude coarse grain clay saline soil and crude fine particle saline soil after the testing of freezing and thawing cycles,these crude saline soil samples are selected for the experiment of freezing and thawing cycles on the results of testing saline soil samples of two places（Gansu and Sinkiang,China）.In addition,the effects of the microstructure of crude saline soil after the testing of freezing and thawing cycles are researched by using SEM.It shows that salt expansion value of crude coarse grain clay saline soil is accumulated before the seventh freezing and thawing cycles,but soil body could be dented in the process of cooling and collapsibility value is accumulated with increasing cycles;the salt expansion value of crude fine particle saline soil is accumulated with increasing cycles,but after the sixth cycles the increment is reduced gradually in the process of temperature rise,and the variation of salt expansion ratio is a parabolic function of freezing and thawing cycles.