土的化学加固经常需要借助细观试验手段评估加固材料带来的土原有的不同尺度层次微细观结构的改变,进而揭示加固机制和评估加固效果。本文设定未浸5%浓度K2Si O3溶液、浸1次烘干、浸3次烘干3种黏性土SEM样品,分别进行500倍50μm,1 000倍10μm和5 000倍5μm试验条件的SEM试验。经过对比分析试验图像唯象解析、灰度分割累积曲线和分布曲线、16个分区统计灰阶不同统计特征值(灰阶平均值、标准差和变异系数)的雷达图,图像中团块和片状结构边缘明显增加,累积曲线的变陡,分布曲线的抬高,变异系数雷达图的缩小和均匀化,均佐证了加固效果,综合认定:浸3次5%浓度K2Si O3溶液的加固方案最优,该方案下强化的不仅是土的团块结构,孔隙也部分充填,加固是全面的,均匀性较好,有利于整体性的发挥,尤其适用于文物保护;SEM试验条件设定在500倍50μm时,分区统计绘制的变异系数雷达图形状因子均随着浸次和放大倍数的增加而单调增加,有利于观察整体加固效果,观测到的是土的团块结构。SEM试验条件设定在5 000倍5μm时,分区统计绘制的变异系数雷达图形状因子均随着浸次和放大倍数的增加而单调减小,有利于观察填充效果,观测到的是土的片状结构;图像中蕴含的量化信息的统计特征值分析中平均值和标准差的表现稳定性和规律性没有变异系数好,建议图像量化分析中多使用变异系数。
Chemical reinforcement of soil often evaluates change of initial micro-structure under different sizes affected by strengthening material by means of all kinds of meso-tests,which reveals strengthening mechanism and estimates reinforced effect. Three types of SEM specimen such as clay without saturated by 5% concentration k2 Si O3 solution,clay with saturated and dried once by the solution and clay with saturated and dried three times by the solution are prepared and respectively used to test under different SEM experiment conditions such as amplification 500 and 50 μm,amplification 1 000 and 10 μm and amplification 5 000 and 5μm. Phenomenological analysis of images,accumulation curve and distribution curve of ray segmentation,radar of different gray statistics(such as average,standard deviation and coefficient of variation) on sixteen subarea of images are compared and analyzed. Apparent enhancement of particle and flake edge in SEM images,sharpening of accumulation curve,elevation of distribution curve and reduction homogenization of variation coefficient radar are all proved reinforcement effect. Clay with saturated and dried three times by 5% concentration K2 Si O3 solution is integrated to be optimal reinforcement scheme,in which not only particle of soil is strengthened but also pore is partly filled. The reinforcement is comprehensive,whose homogenization is better than raw one,which does good to full play of integrity and is suitable for protection of cultural relics. If SEM test condition is designed to be amplification 500 50 μm,shape factor of radar on variation coefficient of sixteen subarea in images increases with increasing of saturated dried time and amplification,which do good to observe whole reinforced effect and micro-structure being particle. When amplification 5 000 5 μm being set in SEM tests,the shape factor curve decreases with increasing of saturated dried time and amplification,which is beneficial to observe pore partly filled effect and micro-structure being flake. During stat