In order to investigate the relationship between the shear strength of residual soil and the number of repeated wet-dry cycles it underwent, the direct shear for different water content, different numbers of wet-dry cycles and different vertical stresses were examined. Based on the comprehensive structural potential theory, a comprehensive structural potential model considering the water content, the number of wet-dry cycles and the vertical stress was constructed. Then, the internal relationship between microstructure characteristics and structural strength attenuation of residual soil under alternate wet-dry conditions was emphatically discussed. As the number of wet-dry cycles and water content increased, the structural variability provided by the soil particle arrangement increased, while the structural stability provided by the soil particle cohesion decreased, causing the shear strength and structural potential of the soil to show a downward trend. As vertical stress increased, the variation range of structural stability was greater than that of structural variability. This asynchronous change caused decreased soil structural potential m_τ. Under the same levels of vertical stress and the same water content, the model we constructed well represented the exponentially decreasing trend between the structural potential and the increased number of wet-dry cycles. Scanning electron microscope (SEM) images of the sample after five wet-dry cycles showed that the surface layer had lifted and the overhead structure between aggregates was clear, suggesting that unit cell connections had changed from face-to-face contact to edge-to-surface contact. That is, the overall orientation of the unit cell was diminished. As the successive wet-dry progressed, the overhead structure provided a more open water migration channel. The nuclear magnetic resonance (NMR) test showed that the content of micropores in soil samples decreased, and the proportion of mesopores and macropores increased, resulting in a decrease in soil strength. With the further development of wet-dry cycles (>5), the peak and residual strength of the soil gradually decreased to be stable. This is related to the decrease in soil saturation after multiple wet-dry cycles, and the stronger the stabilizing effect provided by soil–water meniscus.

为了研究残余土的剪切强度与其经历的重复干湿循环次数之间的关系，研究了不同含水量、不同干湿循环次数和不同垂直应力下的直接剪切。基于综合结构势理论，构建了考虑含水量、干湿循环次数和垂向应力的综合结构势模型。然后重点讨论了干湿交替条件下残余土微观结构特征与结构强度衰减的内在关系。随着干湿循环次数和含水量的增加，土壤颗粒排列提供的结构变异性增加，而土体颗粒内聚力提供的结构稳定性下降，导致土体的抗剪强度和结构潜力呈下降趋势。随着竖向应力的增加，结构稳定性的变化幅度大于结构变异性的变化幅度。这种异步变化导致土壤结构潜力下降米_τ. 在相同水平的垂直应力和相同的含水量下，我们构建的模型很好地代表了结构潜力与干湿循环次数增加之间的指数下降趋势。样品经过 5 次干湿循环后的扫描电子显微镜 (SEM) 图像显示，表层已抬起，聚集体之间的顶部结构清晰，表明晶胞连接已从面对面接触变为边缘到边缘。 -表面接触。即，晶胞的整体取向减少了。随着干湿交替的进行，架空结构提供了一个更加开放的水运移通道。核磁共振（NMR）测试表明，土壤样品中微孔含量降低，中孔和大孔比例增加，导致土壤强度下降。随着干湿循环的进一步发展（>5），土体的峰值强度和残余强度逐渐下降，趋于稳定。这与多次干湿循环后土壤饱和度降低有关，而土壤-水弯月面的稳定作用越强。