饱和盐渍土的一维蠕变试验与模型研究

One-dimensional creep tests and model studies on saturated saline soil

饱和盐渍土中土颗粒和孔隙盐溶液间相互的物理化学作用对土体的力学行为有较强的影响,使得盐渍土表现出不同的变形特性。为了能够准确地描述饱和盐渍土的这种相互作用,首先采用常规固结试验和恒载蠕变试验对通过蒸馏水、硫酸钠溶液和氯化钠溶液饱和后的重塑土样进行了试验研究。试验结果显示:盐渍土和非盐渍土的固结蠕变存在明显差异,此类现象会随着含盐量的增加而更加明显;而同含盐量的硫酸盐渍土和氯盐渍土的固结蠕变效应也不尽相同。其次,基于Yin-Graham一维蠕变方程,利用Pitzer离子相互作用模型和Van’tHoff渗透吸力方程,通过引入有效渗透应力,建立了饱和盐渍土的一维蠕变理论模型。最后,将改进的理论模型与试验数据进行了对比分析。结果表明,所提出的理论模型不仅能够描述饱和盐渍土中化学力学耦合,而且可以有效地预测一维蠕变行为。

The physical and chemical interaction between soil particles and pore salt solutions in saturated saline soils has a strong influence on the mechanical behavior of soils, which makes the saline soils exhibit different deformation characteristics. In order to accurately describe this interaction of saturated saline soil, the experimental studies on the remolded specimens saturated with distilled water, sodium sulfate solution and sodium chloride solution are carried out by the conventional oedometer tests and constant load creep tests. The test results show that there is a significant difference in the consolidation creep between saline soils and non-saline soils. This phenomenon is more obvious with the increase of salt content. The consolidation creep effect of sulphate soils and chloride soils with the same salt content is different. Secondly, based on the Yin-Graham one-dimensional creep equation, a one-dimensional creep theoretical model for saturated saline soils is established by using the Pitzer ion interaction model and the van’t Hoff osmotic suction equation and introducing the effective osmotic stress. Finally, the improved theoretical model and experimental data are compared and analyzed. The results show that the proposed theoretical model can describe the chemical-mechanical coupling in saturated saline soils and effectively predict the one-dimensional creep behavior.