粉土干化过程中微观结构的演变

发布时间：2018-06-02 13:48

本文选题：土力学 + 粉土　；参考：《岩石力学与工程学报》2017年10期

【摘要】：对黏粒含量为34%的粉土泥浆样进行无宏观裂缝出现的慢速干化试验,对干化至不同目标含水率的试样进行压汞试验,获得孔隙分布曲线,系统地研究干化过程中粉土微观结构的演变规律,分析微观裂隙的形成及发展机制。研究结果表明:随着干化的发展,最大进汞量逐渐减小,当含水率达到缩限后,最大进汞量保持不变;不可侵入孔随干化逐渐增多,当含水率小于缩限后,不可侵入孔增大的趋势减缓;当含水率大于缩限前,孔径分布(PSD)曲线峰值对应孔径随干化呈单调递减的关系,含水率继续减小至缩限以下时,峰值对应孔径逐渐增大至固定值;由饱和到非饱和过渡时,PSD曲线在0.1~1?m范围有隆起并达到最大,随着干化的深入,隆起减小直至消失。PSD曲线峰值孔径随干化先减小后增大的趋势以及隆起随干化的变化规律,均证明干化过程中有可能产生微观裂隙,并反映了微观裂隙的演变过程。粉土泥浆样干化过程中,当由饱和过渡到非饱和状态时,黏土会像"外套"一样裹在粉土颗粒周围,微观裂隙在黏土颗粒间及黏土颗粒与粉土颗粒间的交界面上开始出现,该微观裂隙和宏观干燥裂缝在本质上是不同的,是对土体龟裂研究机制的补充。
[Abstract]:The slow drying test without macroscopic cracks was carried out on the silty soil slurry sample with 34% clay content. The pore distribution curve was obtained by mercury injection test on the sample dried to different target moisture content. The evolution law of microstructure of silt during drying is studied systematically, and the formation and development mechanism of microcracks are analyzed. The results show that: with the development of drying, the maximum mercury intake decreases gradually, and the maximum mercury intake remains unchanged when the moisture content reaches the shrinkage limit, and the non-intrusive pore increases gradually with drying, and when the moisture content is less than the shrinkage limit, When the water content is larger than the shrinkage limit, the peak pore size of the pore distribution curve decreases monotonously with drying, and the peak pore size increases to the fixed value when the water content continues to decrease below the shrinkage limit. In the transition from saturation to unsaturated, the PSD curve has a uplift in the range of 0.1 m and reaches the maximum. With the deepening of drying, the peak aperture of the curve decreases until it disappears, and then increases with the drying, as well as the variation law of the uplift with drying. It is proved that microcracks may occur in the drying process and reflect the evolution of microcracks. In the drying process of silt mud, when the clay is transferred from saturation to unsaturated state, the clay will be wrapped around the silt particles like a coat, and the micro-cracks will begin to appear in the interface between clay particles and silt particles. The micro crack is different from the macro dry crack in essence and is a supplement to the mechanism of soil crack research.
【作者单位】：上海大学土木工程系;法国国立路桥学校Navier实验室;
【基金】：国家自然科学基金资助项目(41572284) 国家留学基金项目(201406895026) 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实验室开放课题项目(Z013008)~~
【分类号】：TU41

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