Skip to content

Soil Mechanics & Geotechnical Engineering: A Public-Domain Reference

About this reference

This is an original, open technical reference on soil mechanics and geotechnical engineering, written in plain engineering language. Like the Foundation Engineering book, it is built entirely from public-domain sources — the FHWA NHI Soils and Foundations Reference Manual and the USACE Engineering Manuals, all of which are U.S. Government works in the public domain. No copyrighted textbook is reproduced. It is provided for education and field use; every site is unique and this reference builds engineering judgment, not minimum standards. The underlying manuals are indexed in the GTI Doctor AI assistant.

Soil mechanics is the science of how soil — a three-phase material of solids, water, and air — responds to stress and water. It is the foundation of every geotechnical calculation: bearing capacity, settlement, slope stability, earth pressure, and seepage all rest on it. This reference covers the classical core — composition and classification, compaction, permeability and seepage, effective stress, consolidation, shear strength, and stiffness — plus the practical matters of in-situ testing, parameter selection, and problem soils.

Scope of this reference

# Chapter What it covers
1 Introduction and Sources Why soil mechanics; the public-domain corpus
2 Soil Composition & Index Properties Phases, unit weights, void ratio, Atterberg limits
3 Soil Classification USCS and AASHTO systems; what they tell the engineer
4 Compaction Proctor tests, moisture–density, field control
5 Permeability Darcy's law, laboratory and field measurement
6 Seepage & Flow Nets Flow nets, uplift, piping, filters
7 Effective Stress & Pore Pressure The principle of effective stress; total vs. effective
8 Stress Distribution in Soil Boussinesq, influence charts, stress increase with depth
9 Consolidation Terzaghi theory, \(c_v\), preconsolidation, rate of settlement
10 Shear Strength Mohr–Coulomb, drained vs. undrained, laboratory tests
11 Stiffness & Stress–Strain Modulus, nonlinearity, small-strain behaviour
12 In-Situ Testing & Parameter Selection SPT, CPT, vane, pressuremeter; choosing parameters
13 Problem Soils Expansive, collapsible, organic, and liquefiable soils
14 Laboratory & Field Testing Program Planning tests to answer design questions

The public-domain sources

Source Title Scope
FHWA-NHI-06-088 (Vol. I) Soils and Foundations Reference Manual Soil properties, classification, compaction, seepage, stress, consolidation, shear strength
USACE EM 1110-2-1906 Laboratory Soils Testing Standard laboratory test procedures
USACE EM 1110-1-1904 Settlement Analysis Consolidation and settlement parameters
USACE EM 1110-2-1902 Slope Stability Shear strength for stability analysis
FHWA-NHI-01-031 (GEC-5) Evaluation of Soils and Rock for Subsurface Investigations In-situ testing and parameter selection

Public domain means reusable. USACE and FHWA manuals are works of the U.S. federal government and are not subject to copyright in the United States. This reference presents them as an original synthesis, not a verbatim copy.

How to use this reference

  • Read it alongside the Foundation Engineering book — this one supplies the soil parameters and mechanics; that one applies them to foundations.
  • Use it with the monitoring books. Pore pressure (Chapter 7) and shear strength (Chapter 10) are the physics behind the Dunnicliff and FHWA instrument references.
  • Ask the GTI Doctor for the underlying manual text.

Parameters are not truth. Every soil parameter carries uncertainty; good engineering bounds it and designs for the range, not a single number.

Featured Video (Academic Society Source — ISSMGE): Official overview of Soil Mechanics and Geotechnical Engineering by the International Society for Soil Mechanics and Geotechnical Engineering.

Complementary Practical Field Resources from RST Instruments & Measurand (Terra Insights)