Subgrade Engineering in Permafrost Regions

The chapter focuses on subgrade engineering in permafrost regions, systematically presenting the similarities and differences between highway and railway subgrades. Key contents include main subgrade diseases caused by altered thermal and hydrogeological conditions, route selection principles, and core design elements (thermal stability, ground temperature zoning, frozen soil types, deformation characteristics). It details designs of embankments, cuts, transition sections, and special structures like crushed rock embankment and ventilation duct embankment. Additionally, protective measures such as drainage systems and retaining walls are addressed. The chapter emphasizes comprehensive engineering strategies to balance permafrost protection and project safety, offering systematic technical guidance for the design, construction, and operation of subgrade projects in permafrost areas.