一维压缩蠕变前后软土的微观结构变化

软土在蠕变前后微观结构的演变,对了解软土的蠕变机理,探讨软土变形与时间关系以及建于软土地基上建筑物的稳定性有重要意义。对黄石地区软土进行一维压缩蠕变试验,提取原状样与蠕变破坏后土样的结构参数,对比分析这些结构参数在蠕变前后的变化规律。建议用丰度与圆形度辅助分析以更真实反映微观结构实际情况,将复杂度作为一个衡量软土在蠕变过程中孔隙或颗粒形状规则程度的重要参数。采用雷达图反映定向频率分布,可以同时对比多组数据,便于观察分布强度。研究结果表明:软土蠕变过程是结构逐渐破损,结构趋向稳定的过程;在蠕变条件下,竖直与水平方向微观异性变得不明显,孔隙变化遵循孔隙均匀化原理,小孔隙数量大量增多,孔隙与颗粒总体形状趋向扁圆形,外形更趋于"圆滑",颗粒定向性变得更有序了,而孔隙定向性变化不明显。

Microstructural change of soft clay before and after one-dimensional compression creep

Microstructural change in soft clay before and after creep is important to understand its creep mechanism, relations between the stain and time, and building stability on the soft ground. One-dimensional compression creep tests on Huangshi area soft clay are carried out, and structural parameters of primary soft clay samples and creep failure samples are gained. The change rules of structural parameters before and after creep are analyzed. The abundance distribution analysis with circularity is proposed for real reflection of microstructure, and complexity is regardedas the key parameter in the creep process. Radar chart used for showing directionality frequency distribution and simultaneously comparing many groups of data is advantageous for the observation of distributed intensity. The results show that the creep process is the gradual structural damage and structure trends to be stable. Under the creep condition, the micro-anisotropy is not obvious, micro-pore size change follows the theory of homogeneity, and the quantity of fine pores increases massively. Pores and particle shape trend to be oblate and smooth, the particle directionality becomes more ordered, but pore directionality change is not obvious.