利用粉晶X射线衍射、扫描电镜(SEM)、土水化学效应试验和现场大型剪切试验等手段对角砾土在浸水前后两种状态下的矿物、化学组分和微观结构及抗剪强度等变化特征进行表征。结果显示:矿物遇水后X射线衍射强度增加,大量钙镁质胶结物溶于水继而与阳离子发生交换作用,浸水后2 d左右浓度趋于稳定;浸水后的样品中出现大孔隙,样品中片状黏土矿物颗粒呈定向排列。大剪试样结果表明,原状角砾土具有较强的结构强度,浸水后黏聚力降低31%,而内摩擦角降低19%,水对黏聚力的影响高于对内摩擦角的影响。黏土矿物遇水细微观结构定向排列是角砾土内部结构产生损伤的主要原因,钙镁胶结物溶解与阳离子置换作用是试样抗剪强度衰减的直接结果。以上研究成果为遇水作用下冰水堆积物的结构损伤进行检测提供了依据,并丰富了对理县冰水堆积体的强度衰减机制认识。 By means of powder X-ray diffraction, scanning electron microscopy (SEM), chemical reaction of soil water and large-scale shear test in the field, the mineral, chemical composition, microstructure and shear strength of breccia soil before and after soaking in water And other characteristics of the changes were characterized. The results show that the intensity of X-ray diffraction increases when the mineral meets water, and a large amount of calcium magnesian cement dissolves in water and then exchanges with the cation, and the concentration becomes stable about 2 d after immersion. Macropores appear in the sample after immersion, Flaky clay mineral particles were oriented. The results of the large shear specimen show that the intact brecciated soils have strong structural strength, the cohesion decreases 31% after immersion and the internal friction angle decreases by 19%, and the effect of water on the cohesion is higher than that on the internal friction angle . The micro-structure orientation of clay minerals is the main reason for the damage of the internal structure of the gravelly soil. The dissolution of calcium-magnesium cement and cation displacement are the direct results of the decay of shear strength of clay samples. The above research results provide the basis for detecting the structural damage of ice water deposits under the action of water and enrich the understanding of the intensity attenuation mechanism of ice water accumulation in Lixian County.