中文摘要：

通过单轴压缩微细结构试验，采集了红砂岩的微细结构图像系列，提取了微细结构量化参数，对不同风化程度红砂岩在单轴压缩条件下微细结构的演化规律进行了分析．试验结果表明：在单轴压缩条件下，红砂岩的内部结构将经历劣化减弱、稳定劣化、加速劣化以及破坏4个阶段；随荷载的增加，红砂岩的颗粒面积比例总体上趋于减小，颗粒定向性逐渐减弱，较大颗粒逐渐破碎，导致其平面分布越来越分散；孔隙的变化趋势恰好与颗粒相反．同时，还研究了不同风化程度红砂岩的水理特性和膨胀特性．研究结果为荷载作用下岩石微细结构演化规律研究及相应本构关系的建立提供了重要的依据．

英文摘要：

The results indicate that the red sandstone＇s initial structure experiences four stages： degradation weakening, degradation stabilizing, degradation quickening and failure under uniaxial compression; grains＇ area ratio is decreasing as a whole; grains＇ directionality gradually weakens, larger grains gradually break and grains distribute more and more decentralized in company with load increasing; pores＇ developing trend is in contradiction with grains＇. At the same time the mechanism how water influences mechanical properties of red sandstones and swelling characteristics have been studied. Therefore, the study results have provided the important basis for studying law of microstructural evolvement of rock under loads and establishing corresponding constitutive equation.