二灰土渗透系数随龄期变化的微细结构分析

为解释二灰土的宏观物理特性,在进行常规的二灰土渗透试验后,利用岩土材料微细结构光学测试系统拍摄了二灰土的微细结构序列图像。采用数字图像处理方法从二灰土初始状态微细结构图像以及养护7 d,14 d和28 d后的微细结构图像中获取所需的微细结构参数,对其进行分析,揭示二灰土渗透系数随龄期变化的宏观现象。结果表明,随着龄期的增长,二灰土颗粒面积比例不断增大,颗粒圆度、孔隙定向度和孔隙分布分维数不断减小,微观试验参数的变化很好地解释了宏观试验所得出的渗透系数随龄期逐渐减小的变化规律。

Microstructure analysis of effect lime-ash soil on permeability coefficient variation with duration

To illustrate the macro-physical characteristics of lime-ash soil,microstructure images of lime-ash soil were taken by the optics test system after the permeability test was carried out.Using a digital image processing method,the microstructure parameters of lime-ash soil were obtained from original state images and images after 7 days,14 days,and 28 days.Through the analysis of microstructure parameters,the macro-phenomena of the permeability coefficient change with maintenance duration of lime-ash soil are explained.It can be concluded that the percentage of surface area of lime-ash soil particle increases with duration,while the roundness of soil particles,the value of pore orientation,and the value of pore fractal dimension continuously decrease with duration.Thus,the variation rule of the permeability coefficient decline with the duration of lime-ash soil can be well illustrated by the change of the microstructure parameters.