考虑含水率和干湿循环影响的原状黄土孔隙微观结构研究

Pore microstructure of original loess considering water content and drying-wetting cycle effects

为了明确不同含水率和干湿循环作用下原状黄土的微观结构特征,以陕西洛川黄土为研究对象,对不同含水率和干湿循环条件下的原状黄土的微观结构变化进行了研究。研究结果表明,含水率的增大和干湿循环作用均会使得原状黄土大孔隙的平均孔隙直径和孔隙数目增多、孔隙形态更趋于椭圆以及孔隙边缘形态更趋于简单、孔隙排列更趋于定向和有序。孔隙大小特征及数目的变化主要是水分溶解胶结物质,使得不同孔隙贯通和扩张所造成;孔隙形态和排列特征的变化主要是水分的运动以及胶结物质的迁移导致颗粒的移动和摩擦等作用形成。

The loess in Luochuan City of Shaanxi Province was taken as the research object to study the microscopic structural characteristics of the original loess under different water content and drying-wetting cycle,and the condition of different water content and drying-wetting cycle was measured by scanning electron microscope.The microscopic structural changes of original loess were analyzed.The results show that the increase of water content and drying-wetting cycle will increase the average pore diameter and pore number of undisturbed loess macropores.The pore shape tends to be ellipse,the pore edge shape tends to be simple,and the pore arrangement tends to be directional and orderly.The change of pore size and number is mainly caused by the penetration and expansion of different pores caused by water dissolving cemented materials.The change of pore morphology and arrangement characteristics is mainly caused by the movement of water and the migration of cementing substance,which leads to the formation of particle movement and friction.