Degradation of the Soil Skeleton

This chapter discusses skeleton-degradable soils, which are soils whose skeletons can experience mass loss and particle breakage owing to external loads and biochemical reactions. These processes ultimately alter the particle size distributions and pore structures of the soils, thereby influencing soil properties such as strength, deformation, and permeability. First, the soil skeleton degradation process is categorized into the following based on distinct mechanisms: particle breakage, chemical degradation, and biochemical degradation. Among these, soil particle breakage is examined under both static and dynamic loading scenarios, followed by the introduction of a model capturing the evolution of the particle breakage process. Subsequently, the chemical degradation of soils is delineated, particularly the decomposition processes of hydrates and patterns of the associated solid-phase mass loss. Thereafter, the biochemical degradation of MSW is elucidated, emphasizing the development of unified equations. These equations form the basis for constructing models to capture the anaerobic and aerobic degradation behaviors of MSW, thus facilitating the investigation of degradation patterns under both conditions. By comprehensively exploring these degradation pathways, this chapter offers valuable insights into the profound impacts of soil skeleton degradation on soil properties, distinguishing skeleton-degradable soils from conventional ones.