Every geotechnical decision begins with one question: what is this soil? Most courses teach you to answer it with a symbol and stop. This course treats the symbol as the beginning. From a soil’s name follow its permeability, its compressibility, its strength, its hazards, and the design checks it demands. That chain, from classification to design input parameters and the testing decisions that follow, is what you will master here.
A complete path, not a topic. Nine modules run from the clay minerals and the phase diagram, through the Atterberg limits and mechanical analysis, into the USCS, AASHTO and USDA systems, then out to the field: visual identification by hand, the SPT and CPTu with their full correction chains, the field vane, the boring log, and the first design applications. A capstone, the Mega Field Problem, takes one complete site investigation from raw field sheets to a defensible ground model, formula first at every step.
Classification connected to design. You will learn to read a group symbol as a prediction: which soils drain freely and which consolidate for years; which classes swell, collapse, pipe, or liquefy; why a loose saturated SP below the water table is a liquefaction case, why a high activity CH demands moisture control and founding depth, and why a gap graded soil calls for a designed filter. The same symbol plans the rest of the investigation: it tells you which strata justify consolidation testing, which call for shear strength testing, which must be screened for swell or collapse, and which in situ tool belongs in the next borehole, the SPT in sands or the CPTu and the field vane in soft clays.
