Q2黄土浸水前后微观结构变化研究

对陕西蒲城电厂Q2黄土浸水前后的试样进行微观结构对比测试，得到了大量珍贵的微观结构图片。浸水前后Q2黄土的微观结构定性、定量分析表明：架空孔隙受力作用影响较大，对水的作用敏感；粒间孔隙对压力和水的作用相对较迟钝；Q2黄土的湿陷峰值压力大于200 kPa。随着压力的增大，Q2黄土的灰度熵、欧拉数和孔隙的面积比例、圆形度、定向度、分布分维减小；而颗粒的面积比例、圆形度、定向度、分布分维将增大；随着水的浸入，各量将继续减小或增大；浸水后孔径大于20 ?m的孔隙含量减少，孔径小于20 ?m的孔隙含量增加，湿陷的过程中大部分孔隙都在发生变化，大孔隙变成中、小孔隙，中、小孔隙则变为更小的孔隙。浸水前后微观结构的变化能较好地解释Q2黄土特殊的湿陷性。

Research on microstructure of Q2 loess before and after wetting

The microstructure changes of Q2 loess in Pucheng power plant, Shaanxi province before and after wetting are studied by using Quanta ESEM (environment scanning electron microscope). A lot of microstructure pictures are obtained. The microstructure qualitative analysis results of Q2 loess before and after wetting with different pressures show that the intra-particle pores are more sensible to pressure and water than inter-particle pores. The maximum pressure of collapsibility of Q2 loess is more than 200 kPa. The area proportion, the roundness, the orientation and the distribution fractal dimension of pore, the gray entropy, the Euler value decrease with increase of pressure and wetting; however, the area proportion, the roundness, the orientation and the distribution fractal dimension of particle increase with pressure and wetting. The quantities of pores with diameter greater than 20 ?m during wetting; while the quantities of pores with diameter less than 20 ?m the pore content increases during wetting. Most pores change during wetting; the large pores turn into medium and small pores; the medium and small pores turn into smaller pores. The peculiar collapsibility of Q2 loess can be explained well by the microstructure changes of Q2 loess before and after wetting with different pressures. The microstructure qualitative analysis provides a new method to research the mechanisms of collapsibility of loess.