硫酸(亚硫酸)盐渍土单次盐胀和冻胀发育规律研究

A Study on Single-cycle Salt and Frost Heaving of Sulfate (Sulfurous) Saline Soil

对盐胀和冻胀规律的研究有助于深入认识硫酸(亚硫酸)盐渍土的工程性质。通过对天山北麓水磨河流域细土平原区硫酸(亚硫酸)盐渍土盐胀和冻胀试验研究发现:(1)随着温度的降低,试样盐胀和冻胀率逐渐增大。试样冻结前土体产生的膨胀是盐胀,试样冻结后产生的膨胀是盐胀和冻胀,当土体达到-15℃以后,土体盐胀和冻胀趋于稳定。(2)硫酸钠含量不变的情况下,随着含水量的增大,其起胀温度降低。土体起胀温度取决于土体中硫酸钠析水结晶温度、硫酸钠结晶含量的多少、土体结构、内摩阻力、粘聚力、土颗粒间的引力、土体孔隙间和孔隙接触间吸收结晶硫酸钠的程度。(3)硫酸钠含量增加,其单次盐胀和冻胀率变化区间增大。

Research about salt and frost heaving is helpful to further know the engineering properties of sulfate （sulfurous） saline soil. In order to find the characteristics of salt and frost heaving, the authors introduce the results of the tests of single-cycle salt and frost heaving for the sulfate （sulfurous） saline soil on fine soil plain of Shuimohe Valley in north Tianshan. The test results show that： （1） The single-cycle salt and frost heaving rate increases with the decrease of temperature, and the soil expansion is mainly salt heaving before soil frozen but salt-frost heaving after frozen. The salt-frost heaving tends to stable when below -15℃. （2） The inception temperature of heaving decreases with increase of water content in the same sulfate content, and it depends on sodium sulfate crystallization temperature, sodium sulfate crystal content, soil microstructure, internal frictional resistance, cohesion, attraction among soil particles and extent of adsorption of sodium sulfate in void. （3） The single-cycle salt and frost heaving rate interval increases with increase of sulfate content.