GEOTECHNICAL ENGINEERING LESSON 1

is defined as the uncemented aggregate of mineral grains and decayed organic matter (solid particles) with liquid and gas in the empty spaces between the solid particles

Soil

Soil is defined as the _______ and ______ with liquid and gas in the empty spaces between the solid particles

uncemented aggregate of mineral grains
decayed organic matter (solid particles)

Soil is composed of

45% - Mineral
25% - Air
25% - Water
5% - Organic Matter

is the branch of science that deals with the study of the physical properties of soil and the behavior of soil masses subjected to various types of forces

Soil Mechanics

is the application of the principles of soil mechanics to practical problems

Soils Engineering

is the subdiscipline of civil engineering that involves natural materials found close to the surface of the earth

Geotechnical Engineering

is includes the application of the principles of soil mechanics and rock mechanics to the design of foundations, retaining structures, and earth structures

Geotechnical Engineering

time span on the emphasis and the nature of study in the area of geotechnical engineering

1700 to 1927

four major periods

Preclassical (1700 to 1776 A.D.)
Classical soil mechanics – Phase I (1700 to 1776 A.D.)
Classical soil mechanics – Phase II (1856 to 1910 A.D.)
Modern soil mechanics (1910 to 1927 A.D.)

A French engineer who studied the natural slopes of soils

Henri Gautier (1660 – 1737)

is the steepest angle of descent or dip relative to the horizontal plane on which the material can be piled without slumping

Natural slope or Angle of repose

Natural slope of clean dry sand

31°

Natural slope of ordinary earth

45°

Unit weight of clean dry sand

18.1 kN/m3

Unit weight of ordinary earth

13.4 kN/m3

He determined the true position of the sliding surface in soil behind a retaining wall using laws of friction and cohesion of for solid bodies

Charles Augustin Coulomb (1736 – 1806)

They studied special cases of Coulomb’s work including inclined backfills and backfills supporting surcharge

Jacques Frederic Francais (1775 – 1833)
Claude Louis Marie Henri Navier (1785 – 1836)

He extended Coulomb’s theory by providing a graphical method for determining the magnitude of lateral earth pressure on vertical and inclined retaining walls

Jean Victor Poncelet (1788 – 1867

He also provided the first ultimate bearing-capacity theory for shallow foundations

Jean Victor Poncelet (1788 – 1867

He published a study on the permeability of sand filters, and defined the term coefficient of permeability which is a very useful parameter in geotechnical engineering

Henry Philibert Gaspard Darcy (1803 – 1858)

He developed the theory of stress distribution under loaded bearing areas in a homogeneous, semi-infinite, elastic, and isotropic medium

Sir George Howard Darwin (1845 – 1912)

He defined clay-size fractions as the percentage by weight of particles smaller than 2 microns in size

Albert Mauritz Atterberg (1846 – 1916)

He explained the consistency of cohesive soils by defining liquid, plastic, and shrinkage limits

Albert Mauritz Atterberg (1846 – 1916)

He developed the theory of consolidation for clays as we know today

Karl Terzaghi (1883 – 1963)

He is also known as the father of modern soil mechanics

Karl Terzaghi (1883 – 1963)

The mineral grains that form the solid phase of a soil aggregate are the product of ______

Rock weathering.

Three basic types of rocks

Igneous rocks
Sedimentary rocks
Metamorphic rocks

are formed by the solidification of molten magma ejected from deep within the earth’s mantle

Igneous rocks

are formed by the accumulation or deposition of mineral or organic particles at the surface of the Earth, followed by cementation

Sedimentary rocks

are formed when existing rock is transformed physically or chemically at elevated temperature

Metamorphic rocks

is the process of breaking down rocks by mechanical and chemical processes into smaller pieces

Weathering

may be caused by the expansion and contraction of rocks from continuous gain and loss of heat, which results in ultimate disintegration

Mechanical weathering

formed by transportation and deposition of glaciers

Glacial Soils

may be caused when rock minerals are transformed into new minerals

Chemical weathering

transported by running water and deposited along streams

Alluvial Soils

formed by deposition in quiet lakes

Lacustrine Soils

formed by deposition in the seas

Marine Soils

transported and deposited by wind

Aeolian Soils

formed by movement of soil from its original place by gravity, such as during landslides

Colluvial Soils

is the determination of the size range of particles present in a soil, expressed as a percentage of the total dry weight

Mechanical analysis

For particle sizes larger than 0.075 mm

Sieve analysis

For particle sizes smaller than 0.075 mm

Hydrometer analysis

consists of shaking the soil sample through a set of sieves that have progressively smaller openings

Sieve Analysis

is based on the principle of sedimentation of soil grains in water. When a soil specimen is dispersed in water, the particles settle at different velocities, depending on their shape, size, weight, and the viscosity of the water

Hydrometer analysis