基于微结构量化分析的软土各向异性特征研究

发布时间：2018-06-17 21:45

本文选题：软土 + 微观结构　；参考：《地下空间与工程学报》2015年S2期

【摘要】：软土的破坏受其微观结构控制,微观结构的形成和黏土矿物及沉积环境密切相关,不同尺度下微观结构的表现形式不同。本文采取温州某工程平原区3.0 m附近的海相沉积软土,设计了100倍200μm、800倍50μm、2000倍20μm的SEM电镜扫描试验。根据SEM试验结果图像对比发现,软土的微观结构分别为200μm对应团块+层状结构、50μm网状结构、20μm絮片状结构;根据图像灰阶统计平均值、标准差和变异系数分区雷达图对比发现,软土在101.25°~146.25°、11.25°~56.25°存在两组近于正交的优势微观结构;灰阶统计特征值雷达图和形状因子均揭示了软土的非均匀性和各向异性,团块+层状结构的非均匀性和各向异性网状结构絮片状结构。这些结构形式及其优势方向会极大影响软土在不同尺度下的破坏形式。灰阶统计特征值中变异系数的表现最稳定最优;形状因子相对于灰度统计特征值能更好的表现非均匀性和各向异性;分析不同微观结构时需要设定不同的SEM试验视窗尺度。
[Abstract]:The failure of soft soil is controlled by its microstructure. The formation of microstructure is closely related to clay and sedimentary environment. In this paper, the marine sedimentary soft soil near 3.0 m in a Wenzhou engineering plain area is used to design the SEM scanning test of 100 times 200 渭 m ~ 800 times 50 渭 m ~ 2 000 渭 m ~ (20 渭 m) SEM. According to the image comparison of SEM test results, the microstructure of soft soil was found to be 200 渭 m corresponding to the stratified block structure of 50 渭 m mesh structure and 20 渭 m floc structure respectively, and the results were compared according to the statistical average of gray scale, standard deviation and coefficient of variation. There are two groups of dominant microstructure of soft soil near orthogonal at 101.25 掳/ 146.25 掳/ 11.25 掳/ 56.25 掳. The grey scale statistical eigenvalue radar map and shape factor reveal the inhomogeneity and anisotropy of soft soil. The inhomogeneity of lamellar structure and the floc structure of anisotropic reticulated structure. These structural forms and their dominant directions will greatly affect the failure modes of soft soil at different scales. The variation coefficient of gray scale statistical eigenvalue is the most stable and optimal; the shape factor can better represent inhomogeneity and anisotropy compared with gray statistical eigenvalue; different SEM test window scale should be set when analyzing different microstructure.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室;
【基金】：国家自然科学基金(50879069,50679073) 水利部公益性行业科研专项资助(2007SHZ1-200701004)
【分类号】：TU447

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