硫酸盐渍土的力学和细观特性试验研究

通过对粉土质砂硫酸盐渍土的CT-三轴剪切试验,得到了硫酸盐渍土的应力-应变关系和剪切过程中试样的CT图像.分析表明:试样表现出明显的剪缩特性；试样均呈塑性破坏；随着围压增加,其应力—应变性状由理想弹塑性过渡到应变硬化；含盐率对盐溃土的强度和变形影响明显,随着硫酸钠的增加,硫酸钠的溶解和降温结晶都会造成土体干密度减小,引起强度降低；含盐率较高时,试样在剪切初期会出现压密阶段.对CT图像的分析表明:随着三轴剪切试验的进行,试样趋于密实和均匀；相同含盐量条件下,CT数均值同体变线性相关性明显.

Research on Mechanical and Microscopical Characteristics of Sulfate Saline Soil

A series of CT-triaxial tests of silty sand including sodium sulfate were carried out,stress-strain relationship and CT images during shear were obtained.Test results indicated: the samples appeared as obvious contraction under shear and took the shape of plastic damage during shear procedure.As ambient pressure increased,stress-strain relationship would convert to strain hardening law from perfectly elasto-plastic state.The strength and volume of saline soil are affected by salt content.The increase of sodium sulfate in soil including both sodium sulfate dissolving and crystallizing will cause the decrease of dry density and soil strength.When the salt content comes to 4% above,there is a compaction state at the beginning of triaxial test.By using of CT images,sulfate saline soil samples become dense and homogenous with the process of shear test.The value of ME is corresponding to linear dependence on volumetric strain when salt content is equal.