LESSON 1 Flashcards by Mark Remiter

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

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used as a construction material in various civil
engineering projects and it supports structural
foundations.

Soil

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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

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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 materials

Geotechnical Engineering

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Application of principles of soil mechanics to
engineering problem:

a. Highway retaining wall
b. Building basement walls
c. Bridge abutments
d. Earth dam
e. Waterfront bulkhead

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Give 3 Examples of Geotechnical Systems:

Dams
Tunnels
Excavations
Slope stabilization
Earth retaining structures
Subgrade support
Ground improvements
Foundation for buildings

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Give An Example of Geotechical Failures:

Leaning Tower of Pisa
Failure of Transcona Grain Elevator

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chemical elements that constitute rocks

Minerals

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the aggregation of minerals into a hard mass

Rocks

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materials that are derived from the weathering
of rocks

Soil

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average particle
diameter of the soil at the 10th percentile or 10% of
the particles are smaller that this diameter size

Effective particle size (D10)

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average particle
diameter of the soil

Average particle diameter (D50)

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numerical measure
of uniformity

Uniformity of coefficient (Cu)

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measure of the shape
of the particle distribution curve (coefficient of gradation/ coefficient of concavity)

Coefficient of curvature (Cc)

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Define As:
Mechanical - process of which rocks are broken into
pieces by physical force (e.g. watre, wind, waves or
ice and frost)
 Chemical - process of chemical decomposition of
the original rock

Weathering

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3 Basic Types of Rocks

Igneous rock
Sedimentary rock
Metamorphic rock

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2 Types of Soil Deposition

Residual and Transported Soil

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soils that are formed by the weathered
products at their place of origin. These soils retain many of
the elements that comprise the parent rock

Residual Soil

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the composition of these soils depends on the environment under which they were
transported and is often different from the parent rock.

Transported Soil

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5 Major Categories of Transported Soils

CLAGAM:

a) Colluvial/ Gravity Transported - soils from
landslides or mudflows
b) Lacustrine - formed by deposition in quiet lakes
c) Alluvial - transported by running water &
deposited along streams
d) Glacial - formed by transportation and
deposition from glaciers
e) Aeolian - transported & deposited by wind
f) Marine - formed by deposition in the seas

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Characteristics of Minerals

-Minerals are crystalline materials and make up the
solids constituent of a soil.
-Minerals are classified according to chemical
composition and structure. -Most minerals of interest
to geotechnical engineers are composed of oxygen
and silicon, two of the most abundant elements on
earth.

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the principal
mineral of coarse-grained soils. A hard and composed of silicon dioxide (SiO2)
in colored, colorless, and transparent hexagonal
crystals

Quartz

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Natural shape of the particles of coarse-grained soil

Angular

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Clay minerals are complex aluminum silicates made of
two distinct structural units. these are:

A. Silicon tetrahedron - silica sheet
B. Alumina Octahedron - Octahedral Sheet/
Gibbsite (Al) sheet or Brucite (Mg) sheet

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3 Clay Minerals

a) Kaolinite b) Illite c) Montmorillonite

consists of repeating layers of elemental silica- gibbsite sheets in 1:1 lattice. The layers are held together by hydrogen bonding and occurs as platelets.  used in paints, paper and in pottery and pharmaceutical industries

Kaolinite

Chemical Formula of Kaolinite

(OH)8Al4Si4O10

kaolinite family; hydrated and tubular structure; (OH)8Al4Si4O10 • 4H2O

Halloysite

consists of gibbsite sheets bonded to two silica sheets - one at the top and another at the bottom, also bonded by potassium ions

Illite

Illite sometimes called as

Clay mica

Has a structure similar to that of illite - one gibbsite sheet sandwiched between two silica sheets. There is isomorphous substitution of magnesium and iron for aluminum in the octahedral sheets. Potassium ions are not present as in illite and large amount of water is attracted into the space between the layers.  A highly reactive (expansive - swells on contact with water) clay

Montmorillonite

Also called smectite; expands on contact with water

Montmorillonite

Chemical Formula of Montmorillonite

(OH)4Al4Si8O20 • nH2O - high affinity to water

montmorillonite family; used as drilling mud, in slurry trench walls, stopping leaks

Bentonite

Soil particles are assumed to be rigid. During deposition, the mineral particles are arranged into structural frameworks

Soil Fabric

Types of soil fabric

Flocculated structure (saltwater environment) particles tend to orient parallel to one another.  Flocculated structure (freshwater environment) - particles oriented in perpendicular manner  Dispersed structure Occurs when majority of the particles orient parallel to one another.

3 Major Categories of Particle Shape

Bulky particles Flaky Particles Need-Shape Particles

A particle shape mostly formed by mechanical weathering of rock and minerals.

Bulky particles

Particle Shape with very low sphericity, predominantly clay minera

Flaky Particle

Descriptions of bulky particles

a) Angular b) Sub-angular c) Rounded d) Sub-rounded

Particle shape that is less common than the two other particle types. Examples are some coral deposits and attapulgite clays.

Needly-shaped particle

What are 3 soil types

1. Gravel 2. Sand 3. Clay and Silt

(Soil Type) pieces of rocks with occasional particles of quartz, feldspar, and other minerals

Gravel

(soil type) mostly made of quartz and feldspar

Sand

( Soil Type) consists of very fine quartz grain, mostly flake-shape microscopic and submicroscopic particles of mica, clay mineral and others

Clay and Silt

Determination of size range of particles present in a soil, expressed as % of the total dry weight.

Mechanical Analysis of Soil

2 methods of Mechanical Analysis of Soil

1. Sieve Analysis 2. Hydrometer Analysis

(True of False ) Sieve Analysis is for particle sizes smaller than 0.075 mm in diameter

False

(True or False) Hydrometer Analysis - for particle sizes larger than 0.075 mm in diameter

False

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

Sieve Analysis

based on the principle of sedimentation of soil grains in water

Hydrometer analysis

4 Parameters determined from the particle size distribution curve:

1. Effective Size (D10) 2. Uniformity Coefficient (Cu) 3. Coefficient of gradation (Cc) 4. Sorting Coefficient (S0)

diameter in the particle-size distribution curve corresponding to 10% finer. It is a good measure to estimate the hydraulic conductivity and drainage through soils.

Effective Size (D10)

defined as: Cu = (D60)/(D10)

Uniformity Coefficient (Cu)

defined as: Cc = (D²30)/((D60)(D10))

Coefficient of gradation (Cc)

another measure of uniformity and is generally encountered in geologic works, expressed as: S0 = √((D75)/(D25))

Sorting Coefficient (S0)

Different Types Of Particle-distribution Curve

 Curve I (Poorly Graded)  Curve II (Well Graded)  Curve III (Gap Graded)

(Curve Type) represents a type of soil in which most of the soil grains are the same size.

Curve I (Poorly Graded)

(Curve Type) represents a soil in which particle sizes are distributed over a wide range.  Cu for gravel > 4  Cu for sand > 6  Cu for sand & gravel - betweem 1 and 3

Curve II (Well Graded)

(Curve Type) soil might have a combination of two or more uniformly graded fractions.

Curve III (Gap Graded)