This book focuses on skeleton-degradable soils, including three typical degradation processes of soil skeletons: soil particle breakage, chemical degradation, and biochemical degradation. Corresponding degradation models and constitutive models are proposed, and a degradation-consolidation theory is established. The theory overcomes the limitations of classical soil mechanics, such as the constant solid-phase mass assumption, and addresses the neglect of the effects of consolidation on degradation in environmental engineering. The theory provides key theoretical foundations and new analytical perspectives for understanding phenomena such as the degradation-consolidation processes in municipal solid waste landfills, the decomposition and exploitation of natural gas hydrates, and the behavior evolution of geomaterials under the influence of particle breakage. This book offers detailed theoretical insights, rich experimental data, and advanced numerical and physical simulation methods, particularly in environmental hazards prevention and control in municipal solid waste landfills. Hence, it is suitable for researchers, practitioners, and graduate students engaged in soil constitutive relations, multi-field coupling problems, and related fields.