中文摘要：

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0.1～1μm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。

英文摘要：

The drying-induced micro-structure evolution of reconstituted Jossigny silt that contains 34% clay-sized fraction was investigated through mercury intrusion porosimetry tests on samples with different water contents. During the preparation of soil samples,the macro-cracks were avoided as far as possible. The final cumulative intrusion void ratio decreased upon drying and became almost unchanged when the water content was lower than the shrinkage limit. The inaccessible pores increased and reached a stable state during drying. The pore size distribution（PSD） curve was shifted left to smaller diameter. However,further drying led PSD curve to shift right to larger diameter,which represented the special microstructure evolution in silty soil during drying because of the microstructure composition of silty soil. Moreover,a bump in PSD curves at the diameter range from 0.1 to 1 μm indicated the possible occurrence and development of the internal micro-fissures. Once the silt slurry was dried to unsaturated state,the microscopic fissures might begin to develop in the clay fraction that coated the silt grains and in the interface between the silt grain and clay particles. These internal micro-fissures identified in the residual shrinkage stage are different from the macro-cracks due to desiccation.