GEOTECHNICAL ENGINEERING - TOPIC 1

For engineering purposes, ___ 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 soild particles.

soil

It 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

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

Soils engineering

It is the subdiscipline of civil engineering that involves natural materials found close to the surface of the earth. It includes the application of the principles of soil mechanics and rock mechanics to the design of foundations, retaining structures, and earth structures.

Geotechnical Engineering

What are the 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.)

The ___ or the ___ 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

The natural slope of clean dry sand and ordinary earth were ___ and ___, respectively.

31 degrees and 45 degrees

The unit weight of clean dry sand and ordinary earth were recommended to be ___ and ___, respectively

18.1 kN/m³

13.4 kN/m³

He developed the theory of consolidation for clays as we know today. He is also known as the father of modern soil mechanics.

Karl Terzaghi

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

Igneous rocks

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

Sedimentary rocks

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

Metamorphic rocks

It is the process of breaking down rocks by mechanical or chemical processes into smaller pieces.

Weathering

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

Mechanical weathering

This may be caused when rock minerals are transformed into new minerals.

Chemical weathering

People in classical period - phase I

Charles Augustin Coulomb

Jacques Frederic Francais

Claude Louis Marie Henri Navier

Jean Victor Poncelet

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

Studied special cases of Coloumb’s work including inclined backfills and backfills supporting surcharge.

Claude Louis Marie Henri Navier

Extended Coulomb’s theory by providing a graphical method for determining the magnitude of lateral earth pressure on vertical and inclined retaining walls. He also provided the first ultimate bearing-capacity theory for shallow foundations.

Jean Victor Poncelet

People in classical period - phase II

Henry Philibert Gaspard Darcy

Sir George Howard Darwin

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

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

Sir George Howard Darwin

People in Modern soil mechanics

Albert Mauritz Atterberg

Karl Terzaghi

He defined clay - size fractions as the percentage by weight of particles smaller than 2 microns in size. He explained the consistency of cohesive soils by defining liquid, plastic, and shrinkage limits.

Albert Mauritz Atterberg

The transported soils may be classified into several groups, depending on their mode of transportation and deposition.

Glacial Soils

Alluvial Soils

Lacustrine Soils

Marine Soils

Aeolian Soils

Colluvial Soils

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

colluvial soils

formed by transportation and deposition of glaciers

glacial soils

transported and deposited by wind

aeolian soils

transported by running water and deposited along streams

alluvial soils

formed by deposition in the seas

marine soils

formed by deposition in quiet lakes

Lacustrine soils

What are the two methods that are generally used to find the particle-size distribution of soil:

Sieve analysis

Hydrometer analysis

It 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 size larger than 0.075 mm. It consists of shaking soil sample through a set of sieves that have progressively smaller openings.

sieve analysis

For particle sizes smaller than 0.075 mm

hydrometer analysis

It 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