【摘要】 研究目的:盐渍土在我国西部地区广泛分布，研究盐渍土的小应变动力特性，可以为铁路工程设计提供技术支持。本文通过盐渍土GDS共振柱试验系统，对南疆地区盐渍土进行共振柱试验，在不同干密度、Na₂SO₄含量变化条件下探讨盐渍土剪切模量G₀变化规律。对不同Na₂SO₄含量盐渍土进行扫描电镜试验，采用IPP软件对SEM图像进行定量分析，从微观层面分析Na₂SO₄含量对盐渍土剪切模量影响。研究结论:（1）同一含水率和干密度条件下，G₀随Na₂SO₄含量增加而增大；（2）利用Na₂SO₄含量作为状态变量，对Hardin方程进行修正，使Na₂SO₄含量对G₀的影响得到了合理的考虑；（3）由不同Na₂SO₄含量的SEM图像可以发现，随着含盐量增加，Na₂SO₄结晶颗粒越来越多，晶体形态为长柱状，颗粒间的连接方式由片架接触和堆积接触转变为胶结接触；（4）随着Na₂SO₄含量增加，大孔隙面积百分含量明显减小，土体更密实，土颗粒间连接方式的改变是G₀变化的主要原因，Na₂SO₄含量20%为G₀变化的显著性拐点；（5）本研究成果可为盐渍土地区工程设计提供参考。更多还原

【Abstract】 Research purposes: Saline soil is widely distributed in the western region of China. Studying the dynamic characteristics of saline soil can provide technical support for railway engineering design. In this paper, the GDS resonant column test system of saline soil was used to test the saline soil in South Xinjiang. The shear modulus G₀ of saline soil was studied under different dry densities and contents of Na₂SO₄. Scanning electron microscope（SEM） tests were carried out on the saline soil with different Na₂SO₄ contents, and IPP software was used to quantitatively analyze the SEM images. The influence of Na₂SO₄ content on the shear modulus of the saline soil was analyzed from the microscopic level.Research conclusions:（1） Under the same moisture content and dry density, the content of G₀ increases with the increase of Na₂SO₄.（2） The content of Na₂SO₄ is used as the state variable to modify Hardin equation, and the influence of Na₂SO₄ content on G₀ is considered reasonably.（3） SEM images of different Na₂SO₄ contents show that with the increase of salt content, more and more Na₂SO₄ crystal particles are formed, and the crystal morphology is long columnar. The connection mode between particles changes from sheet frame contact and stacking contact to cemented contact.（4） With the increase of Na₂SO₄ content, the percentage of macropore area decreases obviously, and the soil is more dense. The main reason for the change of G₀ is the change of connection mode between soil particles, and 20% Na₂SO₄ content is the significant inflection point of G₀ change.（5） The research results can provide reference for engineering design in saline soil areas.更多还原