As discussed in Chapters 1 and 3, some natural soil-rock inherits weaknesses from the parent material. Such deposits include weathering rocks, residual soils, clay shales, dispersive clays, collapsible silts, soluble carbonate rocks, expansive clay, and organic soils. These types of soil have high compressibility, low shear strength, and are very sensitive to local environments, especially to water, and will cause excessive erosion, excessive ground subsidence, slope failure, and landslides. Because these types of soil-rock have special features, they deserve special attention. In this chapter, we shall discuss the engineering properties of these types of soil-rock as related to various analyses and design for geotechnical projects. The discussion includes origin, distribution, and typical geotechnical properties as well as methods for correction of the weaknesses for the following soils and rocks

• Shales and weathered rocks • Residual soil • Expansive clay • Organic soil (bog, muskeg, and moor soils) • Karst region (sinkhole) • Loess (wind-blown silt) • Dispersive clay • Laterite soil • Alluvial sediments and lacustrine deposits • Saline-alkali soils • Bento nite and others.