Each Geotechnical Manual provides chapters on subsurface investigations (e.g., procedures, equipment, samples, soil and rock classifications, in-situ tests, piezometers), laboratory testing (e.g., classification tests, soil and rock properties), interpretation of engineering properties, pavement subgrade design, roadway slopes and embankments, bridge foundations, earth retaining systems, seismic design, geosynthetics, and construction and post-construction involvement.