Geotechnical Engineering: Soil Formation and History

Vocabulary flashcards covering introductory geotechnical engineering, rock cycles, transported soils, historical milestones, and soil phase properties.

Geotechnical Engineering

The broader sub-discipline of civil engineering that encompasses soil mechanics, rock mechanics, and foundation engineering, involving the application of these sciences to design and construct foundations, retaining walls, and earth structures.

Soil Mechanics

The branch of science that applies principles of mechanics and hydraulics to engineering problems dealing with soils as an engineering material.

Rock Cycle

A continuous and dynamic process through which rocks change from one form to another over geological timescales.

Igneous Rocks

Rocks formed by the solidification of molten magma ejected from deep within the earth's mantle.

Sedimentary Rock

Rocks formed when deposits of gravel, sand, silt, and clay from weathering are compacted by overburden pressure and cemented by agents like iron oxide, calcite, dolomite, and quartz.

Metamorphic Rock

Rocks formed through metamorphism, which alters their composition and texture without melting through heat and pressure, forming new minerals and a foliated texture.

Weathering

The breakdown of rocks into smaller fragments due to physical, chemical, or biological processes such as temperature changes, water, wind, and organisms.

Glacial Soils

Transported soils formed by the movement and deposition of glaciers.

Alluvial Soils

Transported soils carried by running water and deposited along streams.

Lacustrine Soils

Transported soils formed by deposition in quiet lakes.

Marine Soils

Transported soils formed by deposition in the seas.

Aeolian Soils

Transported soils carried and deposited by wind.

Colluvial Soils

Transported soils formed by the movement of soil from its original place by gravity, such as during landslides.

Pre-Classical Era (1700 to 1776 A.D.)

The historical era of soil mechanics concentrated on studies relating to natural slope, unit weights of soils, and semiempirical earth pressure theories.

Henri Gautier

A French scientist who studied the natural slopes of soils in 1717.

Bernard Forest de Belidor

Published a textbook in 1729 proposing a theory for lateral earth pressure on retaining walls.

Francois Gadroy

Reported the first laboratory model test results on a $76\,\text{mm}$-high retaining wall built with sand backfill in 1746.

Jean Rodolphe Perronet

A French engineer who studied slope stability in 1769.

Leaning Tower of Pisa

A famous historical example in Italy illustrating soil-bearing capacity problems prior to the 18th century.

Garisenda Tower and Asinelli Tower

Towers in Bologna, Italy built in the 12th century that exhibited tilting due to soil-bearing capacity issues.

Classical Era Phase I (1776 to 1856 A.D.)

An era in soil mechanics where most developments came from engineers and scientists in France, such as Coulomb's work on retaining walls.

Charles Augustin Coulomb

A French scientist who applied principles of calculus for maxima and minima to the study of retaining walls in 1776.

Gaspard Clair Marie Riche de Prony

French author who included Coulomb's theory in his leading 1790 textbook, Nouvelle Architecture Hydraulique (Vol. 1).

Jean Victor Poncelet

Extended Coulomb's theory in 1840 by providing a graphical method for determining lateral earth pressure magnitude.

Alexandre Collin

Provided details for deep slips in clay slopes, cutting, and embankments in 1846.

Classical Era Phase II (1856 to 1910 A.D.)

A period marked by several laboratory experimental results on sand appearing in engineering literature.

Henri Philibert Gaspard Darcy

Published a landmark study on the permeability of sand filters in 1856.

Joseph Valentin Boussinesq

Developed the theory of stress distribution in 1885.

Osborne Reynolds

Demonstrated the phenomenon of dilatancy in sand in 1887.

Modern Era (1925+)

The current period of geotechnical engineering initiated by Karl Terzaghi's publication of Erdbaumechanik in 1925, which established the principle of effective stress.

Karl Terzaghi

Known as the 'Father of Soil Mechanics' who published Erdbaumechanik in 1925 and developed the theory of consolidation and principle of effective stress.

Albert Mauritz Atterberg

Explained cohesive soil consistency in 1911 by defining liquid, plastic, and shrinkage limits.

Wolmar Fellenius

Developed stability analysis methods for saturated clay between 1918 and 1926.

Soil Three-Phase System

A model representing soil as three distinct constituents: Solid Phase (minerals/organic matter), Liquid Phase (water/fluids in voids), and Gas Phase (air in void space).

Gravel

Soil particles larger than $4.75\,\text{mm}$ in size with bulky, angular to sub-rounded shapes, whose behavior is governed by gravity and inter-particle friction.

Sand & Silt

Soil particles ranging in size from $4.75\,\text{mm}$ down to $0.002\,\text{mm}$ with bulky to slightly elongated shapes.

Clay

Microscopic soil particles smaller than $0.002\,\text{mm}$ with flaky, plate-like shapes, whose behavior is governed by electromagnetic forces and water interaction.

Visual-Manual Procedures

Rapid field tests used to classify soil based on physical reactions to manipulation (such as dry strength and dilatancy) prior to laboratory testing.

Dilatancy

A visual-manual field identification test assessing the reaction of a wet soil pat to shaking in the palm of the hand.