天然盐渍土冻融循环时水盐迁移规律及强度变化试验研究

通过对新疆喀什地区12处天然盐渍土室内基本性质试验分析,选取典型天然盐渍土,在开放系统中进行反复冻融循环条件下的试验研究。研究了天然盐渍土在多次冻融循环时的水分和盐分迁移规律及强度变化特征。试验结果表明:经多次冻融循环,低液限粘土试样水分重分布与盐分重分布有很大的一致性,水分和盐分自下而上迁移;试样粘聚力自下而上线形减小,内摩擦角呈s形分布。含砂低液限粘土试样冻融循环过程中,易溶盐均随水分向冷端面迁移,离子剖面呈现中间大两端小的趋势;试样粘聚力呈反s形分布,内摩擦角均呈s形分布。

A LABORATORY TEST STUDY ON WATER AND SALT MIGRATION IN NATURAL SALINE SOILS AND ASSOCIATED SHEAR STRENGTH CHANGES UNDER FREEZING AND THAWING CYCLES

Through the conventional laboratory testing of saline soil samples collected from twelve different places(Kashi,Sinkiang,P.R.China), the representative crude saline soil samples were selected for the experiment of freezing and thawing cycles in open systems.Moving patterns of water and solute migration and variations of shear strength of the representative crude saline soils were studied for different kinds of soils.The result of the tests shows that moving patterns of water and solute in low liquid limit clay under several freezing and thawing cycles are generally consistent with water and solute migrating upwards.The distribution of cohesion of low liquid limit clay decreases linearly form bottom to top and the distribution of the internal friction angle is in s-shape.Both the water and the solute in low liquid limit clay with sand move to the cold end under freezing and thawing cycles and the profile of ion indicates higher concentration in middle than in both ends.The distribution of cohesion of low liquid limit clay with sand is in reverse s-shape,while the distribution of internal friction angle is in s-shape.