Download - Castillon a#2 Soil Composition 2014-2015
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
1/23
TECHNOLOGICAL UNIVERSITY OF THE PHILIPPINESAyala Blvd. Ermita, Manila
COLLEGE OF ENGINEERING
DEPARTMENT OF CIVIL ENGINEERING
CE 410-4C
SOIL MECHANICS, (Lec)
Assignment No.2
SOIL COMPOSITION
Castillon, Benelle Jose P. Castillon
12-205-161
July 08, 2014
Engr. Jesus Ray M. MansayonInstructor
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
2/23
Mineralogy
is a subset ofgeology specializing in the scientific study
ofchemistry,crystal structure,and physical (includingoptical)properties of
minerals.Specific studies within mineralogy include the processes ofmineral origin and formation, classification of minerals, their geographical
distribution, as well as their utilization.
HISTORY
Early writing on mineralogy, especially on gemstones, comes from
ancientBabylonia,the ancientGreco-Roman world, ancient and
medievalChina,andSanskrit texts fromancient India and the ancient
Islamic World.[1]
Books on the subject included theNaturalis
Historia ofPliny the Elder,which not only described many different
minerals but also explained many of their properties, and Kitab al Jawahir
(Book of Precious Stones) by Muslim scientistAl Biruni.TheGerman
Renaissance specialistGeorgius Agricola wrote works such asDe re
metallica(On Metals, 1556) andDe Natura Fossilium(On the Nature of
Rocks, 1546) which begin the scientific approach to the subject. Systematic
scientific studies of minerals and rocks developed in post-
Renaissance Europe.[1]
The modern study of mineralogy was founded on the
principles ofcrystallography (the origins of geometric crystallography, itself,can be traced back to the mineralogy practiced in the eighteenth and
nineteenth centuries) and to themicroscopic study of rock sections with
the invention of themicroscope in the 17th century.
http://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Babyloniahttp://en.wikipedia.org/wiki/Greco-Romanhttp://en.wikipedia.org/wiki/History_of_Chinahttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/History_of_Indiahttp://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Pliny_the_Elderhttp://en.wikipedia.org/wiki/Al_Birunihttp://en.wikipedia.org/wiki/German_Renaissancehttp://en.wikipedia.org/wiki/German_Renaissancehttp://en.wikipedia.org/wiki/Georgius_Agricolahttp://en.wikipedia.org/wiki/De_re_metallicahttp://en.wikipedia.org/wiki/De_re_metallicahttp://en.wikipedia.org/wiki/De_re_metallicahttp://en.wikipedia.org/wiki/De_re_metallicahttp://en.wikipedia.org/wiki/De_Natura_Fossiliumhttp://en.wikipedia.org/wiki/De_Natura_Fossiliumhttp://en.wikipedia.org/wiki/De_Natura_Fossiliumhttp://en.wikipedia.org/wiki/Renaissancehttp://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Microscopichttp://en.wikipedia.org/wiki/Microscopehttp://en.wikipedia.org/wiki/Microscopehttp://en.wikipedia.org/wiki/Microscopichttp://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/Renaissancehttp://en.wikipedia.org/wiki/De_Natura_Fossiliumhttp://en.wikipedia.org/wiki/De_re_metallicahttp://en.wikipedia.org/wiki/De_re_metallicahttp://en.wikipedia.org/wiki/Georgius_Agricolahttp://en.wikipedia.org/wiki/German_Renaissancehttp://en.wikipedia.org/wiki/German_Renaissancehttp://en.wikipedia.org/wiki/Al_Birunihttp://en.wikipedia.org/wiki/Pliny_the_Elderhttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Mineralogy#cite_note-Needham-1http://en.wikipedia.org/wiki/History_of_Indiahttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/History_of_Chinahttp://en.wikipedia.org/wiki/Greco-Romanhttp://en.wikipedia.org/wiki/Babyloniahttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Geology -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
3/23
MODERN MINERALOGY
Historically, mineralogy was heavily concerned withtaxonomy of the rock-
forming minerals; to this end, theInternational Mineralogical Association is an
organization whose members represent mineralogists in individual countries. Its
activities include managing the naming of minerals (via the Commission of New
Minerals and Mineral Names), location of known minerals, etc. As of 2004 there
are over4,000 species of mineral recognized by the IMA. Of these, perhaps 150
can be called "common," another 50 are "occasional," and the rest are "rare" to
"extremely rare."
More recently, driven by advances in experimental technique (such asneutron
diffraction)and available computational power, the latter of which has enabled
extremely accurate atomic-scale simulations of the behaviour of crystals, the
science has branched out to consider more general problems in the fields
ofinorganic chemistry andsolid-state physics.It, however, retains a focus on the
crystal structures commonly encountered in rock-forming minerals (such as
theperovskites,clay minerals andframework silicates). In particular, the field has
made great advances in the understanding of the relationship between the
atomic-scale structure of minerals and their function; in nature, prominentexamples would be accurate measurement and prediction of the elastic
properties of minerals, which has led to new insight intoseismological behaviour
of rocks and depth-related discontinuities in seismograms of theEarth's mantle.
To this end, in their focus on the connection between atomic-scale phenomena
and macroscopic properties, themineral sciences(as they are now commonly
known) display perhaps more of an overlap withmaterials science than any other
discipline.
http://en.wikipedia.org/wiki/Taxonomy_(general)http://en.wikipedia.org/wiki/International_Mineralogical_Associationhttp://en.wikipedia.org/wiki/List_of_minerals_(complete)http://en.wikipedia.org/wiki/Neutron_diffractionhttp://en.wikipedia.org/wiki/Neutron_diffractionhttp://en.wikipedia.org/wiki/Inorganic_chemistryhttp://en.wikipedia.org/wiki/Solid-state_physicshttp://en.wikipedia.org/wiki/Perovskitehttp://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Tectosilicatehttp://en.wikipedia.org/wiki/Seismologyhttp://en.wikipedia.org/wiki/Earth%27s_mantlehttp://en.wikipedia.org/wiki/Materials_sciencehttp://en.wikipedia.org/wiki/Materials_sciencehttp://en.wikipedia.org/wiki/Earth%27s_mantlehttp://en.wikipedia.org/wiki/Seismologyhttp://en.wikipedia.org/wiki/Tectosilicatehttp://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Perovskitehttp://en.wikipedia.org/wiki/Solid-state_physicshttp://en.wikipedia.org/wiki/Inorganic_chemistryhttp://en.wikipedia.org/wiki/Neutron_diffractionhttp://en.wikipedia.org/wiki/Neutron_diffractionhttp://en.wikipedia.org/wiki/List_of_minerals_(complete)http://en.wikipedia.org/wiki/International_Mineralogical_Associationhttp://en.wikipedia.org/wiki/Taxonomy_(general) -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
4/23
PHYSICAL MINERALOGY
CRYSTAL STRUCTURE- Inmineralogy andcrystallography,crystal
structure is a unique arrangement ofatoms ormolecules in
acrystallineliquid orsolid.A crystal structure is composed of a pattern, aset of atoms arranged in a particular way, and a lattice exhibiting long-
range order and symmetry. Patterns are located upon the points of
alattice,which is an array of points repeating periodically in three
dimensions. The points can be thought of as forming identical tiny boxes,
called unit cells, that fill the space of the lattice. The lengths of the edges of
a unit cell and the angles between them are called thelattice
parameters.Thesymmetry properties of the crystal are embodied in
itsspace group.A crystal's structure and symmetry play a role in
determining many of its physical properties, such ascleavage,electronic
band structure,andoptical transparency.
CRYSTAL HABIT- The crystal habit of a mineral describes its visible
external shape. It can apply to an individual crystal or an assembly of
crystals. Inmineralogy,shape and size give rise to descriptive terms applied
to the typical appearance, or habit ofcrystals.Each crystal can be described
by how well it is formed, ranging fromeuhedral (perfect to near-perfect), tosubhedral (moderately formed), and anhedral (poorly formed to no
discernable habit seen).The many terms used by mineralogists to describe
crystal habits are useful in communicating what specimens of a
particularmineraloften look like. Recognizing numerous habits helps a
mineralogist to identify a large number of minerals. Some habits are
distinctive of certain minerals, although most minerals exhibit many
differing habits (the development of a particular habit is determined by the
details of the conditions during the mineral formation/crystal growth).
Crystal habit may mislead the inexperienced as a mineral's internalcrystalsystem can be hidden or disguised.
http://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Atomhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Solidhttp://en.wikipedia.org/wiki/Bravais_latticehttp://en.wikipedia.org/wiki/Lattice_constanthttp://en.wikipedia.org/wiki/Lattice_constanthttp://en.wikipedia.org/wiki/Lattice_constanthttp://en.wikipedia.org/wiki/Symmetryhttp://en.wikipedia.org/wiki/Space_grouphttp://en.wikipedia.org/wiki/Cleavage_(crystal)http://en.wikipedia.org/wiki/Electronic_band_structurehttp://en.wikipedia.org/wiki/Electronic_band_structurehttp://en.wikipedia.org/wiki/Crystal_opticshttp://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Euhedralhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Euhedralhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/Crystal_opticshttp://en.wikipedia.org/wiki/Electronic_band_structurehttp://en.wikipedia.org/wiki/Electronic_band_structurehttp://en.wikipedia.org/wiki/Cleavage_(crystal)http://en.wikipedia.org/wiki/Space_grouphttp://en.wikipedia.org/wiki/Symmetryhttp://en.wikipedia.org/wiki/Lattice_constanthttp://en.wikipedia.org/wiki/Lattice_constanthttp://en.wikipedia.org/wiki/Bravais_latticehttp://en.wikipedia.org/wiki/Solidhttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Atomhttp://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Mineralogy -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
5/23
CRYSTAL TWINNING- Crystal twinning occurs when two separate
crystals share some of the samecrystal lattice points in a symmetrical
manner. The result is an intergrowth of two separate crystals in a variety of
specific configurations. A twin boundary or composition surface separates
the two crystals.Crystallographers classify twinned crystals by a numberoftwin laws.These twin laws are specific to thecrystal system.The type of
twinning can be a diagnostic tool in mineral identification. Twinning can
often be a problem inX-ray crystallography,as a twinned crystal does not
produce a simplediffraction pattern.
CLEAVAGE-inmineralogy,is the tendency of crystalline materials
to split along definitecrystallographic structural planes. These planes of
relative weakness are a result of the regular locations of atoms and ions in
the crystal, which create smooth repeating surfaces that are visible both in
the microscope and to the naked eye.
LUSTRE- is the way light interacts with the surface of acrystal,rock,
ormineral.The word traces its origins back to thelatin lux, meaning "light",
and generally implies radiance, gloss, or brilliance. A range of terms are
used to describe lustre, such as earthy, metallic, greasy, and silky. Similarly,
the term vitreous(derived from the Latin forglass,vitrum) refers to a glassy
lustre. A list of these terms is given below. Lustre varies over a wide
continuum, and so there are no rigid boundaries between the different
types of lustre. (For this reason, different sources can often describe the
same mineral differently. This ambiguity is further complicated by lustre's
ability to vary widely within a particular mineral species.) The terms are
frequently combined to describe intermediate types of lustre (for example,
a"vitreous greasy" lustre). Some minerals exhibit unusual opticalphenomena, such asasterism (the display of a star-shaped luminous area)
orchatoyancy (the display of luminous bands, which appear to move as the
specimen is rotated). A list of such phenomena is given below.
http://en.wikipedia.org/wiki/Crystal_latticehttp://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/w/index.php?title=Twin_laws&action=edit&redlink=1http://en.wikipedia.org/wiki/Crystal_systemhttp://en.wikipedia.org/wiki/X-ray_crystallographyhttp://en.wikipedia.org/wiki/X-ray_scattering_techniqueshttp://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Latinhttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Asterism_(gemmology)http://en.wikipedia.org/wiki/Chatoyancyhttp://en.wikipedia.org/wiki/Chatoyancyhttp://en.wikipedia.org/wiki/Asterism_(gemmology)http://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Latinhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/X-ray_scattering_techniqueshttp://en.wikipedia.org/wiki/X-ray_crystallographyhttp://en.wikipedia.org/wiki/Crystal_systemhttp://en.wikipedia.org/w/index.php?title=Twin_laws&action=edit&redlink=1http://en.wikipedia.org/wiki/Crystallographyhttp://en.wikipedia.org/wiki/Crystal_lattice -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
6/23
DIAPHANEITY - In the field ofoptics,transparency (also
called pellucidity or diaphaneity) is thephysical property of allowing light to
pass through the material without being scattered. On a macroscopic scale
(one where the dimensions investigated are much, much larger than the
wavelength of thephotons in question), the photons can be said tofollowSnell's Law.Translucency (also called translucence or translucidity),
is a super-set of transparency, allows light to pass through; but, does not
necessarily (again, on the macroscopic scale) follow Snell's law; the photons
can be scattered at either of the two interfaces where there is a change in
index of refraction, or internally. In other words, a translucent medium
allows the transport of light while a transparent medium not only allows
the transport of light but allows for the image formation. The opposite
property of translucency is opacity. Transparent materials appear clear,
with the overall appearance of one color, or any combination leading up to
a brilliant spectrum of every color. When light encounters a material, it can
interact with it in several different ways. These interactions depend on
thewavelength of the light and the nature of the material. Photons interact
with an object by some combination of reflection, absorption and
transmission. Some materials, such asplate glass and cleanwater,allow
much of the light that falls on them to be transmitted, with little being
reflected; such materials are called optically transparent. Many liquids and
aqueous solutions are highly transparent. Absence of structural defects(voids, cracks, etc.) and molecular structure of most liquids are mostly
responsible for excellent optical transmission. Materials which do not allow
the transmission of light are calledopaque.Many such substances have
achemical composition which includes what are referred to
asabsorption centers. Many substances are selective in their absorption
ofwhite lightfrequencies.They absorb certain portions of thevisible
spectrum,while reflecting others. The frequencies of the spectrum which
are not absorbed are either reflected back or transmitted for our physical
observation. This is what gives rise tocolor.The attenuation of light of all
frequencies and wavelengths is due to the combined mechanisms of
absorption andscattering.
http://en.wikipedia.org/wiki/Opticshttp://en.wikipedia.org/wiki/Physical_propertyhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Snell%27s_Lawhttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Plate_glasshttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Chemical_compositionhttp://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)http://en.wikipedia.org/wiki/White_lighthttp://en.wikipedia.org/wiki/Frequencieshttp://en.wikipedia.org/wiki/Visible_spectrumhttp://en.wikipedia.org/wiki/Visible_spectrumhttp://en.wikipedia.org/wiki/Colorhttp://en.wikipedia.org/wiki/Light_scattering_in_liquids_and_solidshttp://en.wikipedia.org/wiki/Light_scattering_in_liquids_and_solidshttp://en.wikipedia.org/wiki/Colorhttp://en.wikipedia.org/wiki/Visible_spectrumhttp://en.wikipedia.org/wiki/Visible_spectrumhttp://en.wikipedia.org/wiki/Frequencieshttp://en.wikipedia.org/wiki/White_lighthttp://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)http://en.wikipedia.org/wiki/Chemical_compositionhttp://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Plate_glasshttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Snell%27s_Lawhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Physical_propertyhttp://en.wikipedia.org/wiki/Optics -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
7/23
STREAK- (also called "powder color") of amineral is thecolor of the
powder produced when it is dragged across an unweathered surface.
Unlike the apparent color of a mineral, which for most minerals can vary
considerably, the trail of finely ground powder generally has a more
consistent characteristic color, and is thus an important diagnostic tool inmineral identification. If no streak seems to be made, the mineral's streak is
said to be white or colorless. Streak is particularly important as a diagnostic
for opaque and colored materials. It is less useful forsilicate minerals,most
of which have a white streak and are too hard to powder easily.The
apparent color can vary widely because of trace impurities or a disturbed
macroscopiccrystal structure. Small amounts of an impurity that strongly
absorbs a particular wavelength can radically change the wavelengths of
light that are reflected by the specimen, and thus change the apparent
color. However, when the specimen is dragged to produce a streak, it is
broken into randomly oriented microscopiccrystals,and small impurities
do not greatly affect the absorption of light.The surface across which the
mineral is dragged is called a "streak plate," and is generally made of
unglazedporcelain tile. In the absence of a streak plate, the unglazed
underside of a porcelain bowl or vase or the back of a glazed tile will work.
Sometimes a streak is more easily or accurately described by comparing it
with the "streak" made by another streak plate.Because the trail left behind
results from the mineral being crushed into powder, a streak can only bemade of minerals softer than the streak plate, around 7 on theMohs scale
of mineral hardness.In case of harder minerals, the color of the powder
can be determined by filing or crushing with a hammer a small sample,
which is then usually rubbed on a streak plate. Most minerals that are
harder have an unhelpful white streak.Some minerals leave a streak similar
to their natural color, such ascinnabar andlazurite.Other minerals leave
surprising colors, such asfluorite,which always has a white streak,
although it can appear in purple, blue, yellow, or green crystals.Hematite,
which is black in appearance, leaves a red streak which accounts for its
name, which comes from the Greek word "haima," meaning
"blood."Galena,which can be similar in appearance to hematite, is easily
distinguished by its gray streak.
http://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Colorhttp://en.wikipedia.org/wiki/Silicate_mineralhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Porcelainhttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Cinnabarhttp://en.wikipedia.org/wiki/Lazuritehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Hematitehttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Lazuritehttp://en.wikipedia.org/wiki/Cinnabarhttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/wiki/Porcelainhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Silicate_mineralhttp://en.wikipedia.org/wiki/Colorhttp://en.wikipedia.org/wiki/Mineral -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
8/23
HARDNESS- The Mohs scale of mineral hardness characterizes the
scratch resistance of variousminerals through the ability of a harder
material to scratch a softer material. It was created in 1812 by the
Germangeologist andmineralogistFriedrich Mohs and is one of several
definitions ofhardness inmaterials science.The method of comparing
hardness by seeing which minerals can scratch others, however, is of great
antiquity, having been mentioned byTheophrastus in his treatise On
Stones, c. 300 BC, followed byPliny the Elder in hisNaturalis Historia,c. 77
AD.
SPECIFIC GRAVITY- is the ratio of thedensity of a substance
compared to the density (mass of the same unit volume) of a reference
substance.Apparent specific gravity is the ratio of the weight of a volume
of the substance to the weight of an equal volume of the reference
substance. The reference substance is nearly alwayswater for liquids or air
for gases. Temperature and pressure must be specified for both the sample
and the reference. Pressure is nearly always 1atm equal to 101.325 kPa.
Temperatures for both sample and reference vary from industry to
industry. In British brewing practice the specific gravity as specified above is
multiplied by 1000.
CHEMICAL MINERALOGY
Focuses on the chemical composition of minerals in order to identify,
classify, and categorize them, as well as a means to find beneficial uses
from them. There are a few minerals which are classified as whole
elements, includingsulfur,copper,silver,andgold,yet the vast majority ofminerals are chemical compounds, some more complex than others. In
terms of major chemical divisions of minerals, most are placed within
theisomorphous groups, which are based onanalogous chemical
composition and similar crystal forms. A good example of isomorphism
http://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/Friedrich_Mohshttp://en.wikipedia.org/wiki/Hardness_(materials_science)http://en.wikipedia.org/wiki/Materials_sciencehttp://en.wikipedia.org/wiki/Theophrastushttp://en.wikipedia.org/wiki/Pliny_the_Elderhttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Water_(molecule)http://en.wikipedia.org/wiki/Atmosphere_(unit)http://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Silverhttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Isomorphismhttp://en.wikipedia.org/wiki/Analogoushttp://en.wikipedia.org/wiki/Analogoushttp://en.wikipedia.org/wiki/Isomorphismhttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Silverhttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Atmosphere_(unit)http://en.wikipedia.org/wiki/Water_(molecule)http://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Naturalis_Historiahttp://en.wikipedia.org/wiki/Pliny_the_Elderhttp://en.wikipedia.org/wiki/Theophrastushttp://en.wikipedia.org/wiki/Materials_sciencehttp://en.wikipedia.org/wiki/Hardness_(materials_science)http://en.wikipedia.org/wiki/Friedrich_Mohshttp://en.wikipedia.org/wiki/Mineralogyhttp://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/Mineral -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
9/23
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
10/23
are families of anions (and their compounds) with the formula [SiO2+n]2n-
.
Important members are the cyclic and single chain silicates {[SiO3]2-
}nand
the sheet-forming silicates {[SiO2.5]-}n. Silicate compounds, including the
minerals, consist of silicate anions whose charge is balanced by
variouscations.Myriad silicate anions can exist, and each can formcompounds with many different cations. Hence this class of compounds is
very large. Both minerals and synthetic materials fit in this class.
SOIL FRAMEWORKSAND COMPOSITION OF GRANULAR SOIL
The structure of silicates
Since Si invariably occurs in tetrahedral coordination the fundamental unitof the silicate structure is the Si-O tetrahedra. The different types of silicate
structure arise from the ways in which these tetrahedra are arranged: they
may exist as seperate unlinked entitites, as linked finite arrays, as infinite 1-
dimensional chains, as infinite 2-dimensional sheets or as infinite 3-
dimensional frameworks. These possibilities give rise to the six primary
structural types of silicates, each with a characteristic Si : O ratio (more
strictly this should be the ratio of tetrahedral cations to oxygen, the reasons
for which are discusssed later):
Orthosilicates (or neosilicates): independent Si-O tetrahedra, Si : 0 = 1 : 4,for example theolivinegroup.
Sorosilicates: two linked Si-O tetrahedra sharing one oxygen, Si : 0 = 2 : 7
Cyclosilicates : closed rings of linked Si-O tetrahedra sharing two oxygens,
Si : 0 = 1 : 3, for example beryl.
http://en.wikipedia.org/wiki/Cationhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/olivine.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/olivine.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/olivine.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/olivine.htmlhttp://en.wikipedia.org/wiki/Cation -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
11/23
Inosilicates: continuous chains of Si-O tetrahedra, sharing two oxygens
(single chains, Si : 0 = 1 : 3, for example thepyroxenegroup) or alternately
sharing two and three oxygens (double chains, Si : 0 = 4 : 11, for example
theamphibolegroup)
Phyllosilicates:Continuous sheets of Si-O tetrahedra sharing three oxygens,
Si : O = 2 : 5, for example the micagroup.
Tektosilicates:Continuous framework of Si-O tetrahedra sharing all four
oxygens, Si : O = 1 : 2, for example thefeldspargroup.
The requirement for charge balance or electronic neutrality in these
different structural types is maintained by the dispersal of other cations in
6-fold (octahedral), 8-fold (cubic) or 12-fold (icosahedral or close packed)
coordintaion between the individual tetrahedra or arrays of tetrahedra in
the silicate structure. For example, in single chained inosilicates (Si : O = 1 :
3) there is a net excess of two negative charges per tetrahedra. (SiO3)n2n-
http://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/pyroxene.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/pyroxene.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/pyroxene.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/amphibole.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/amphibole.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/amphibole.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/amphibole.htmlhttp://jaeger.earthsci.unimelb.edu.au/msandifo/Teaching/Minerals/pyroxene.html -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
12/23
where nis the number of tetrahedra in the chain, and2n-
represents the
charge excess of the chain forming elements. Theoretically the charge
excess could be alleviated in a number of different ways, for example by
adding one bivalent cation or two univalent cations per 3 oxygens.
However, the location of these cations, which must reside in spaces(termed sites) between the individual chains of Si-O tetrahedra, must be
such that they simultaneously satisfy the requirement for electronic
neutrality of all oxygens in the structure. Fortunately, this constraint
severely limits the range of compositions and structures found in the
inosilicates (as indeed it does with all other silicates).
If we look at the detail of the single chain structure we find that in each
tetrahdron there are two linking O atoms that are each bonded to two Si
atoms and two peripheral O atoms each with bonds to only one Si atom.
Since each Si atom shares its 4+ charge with the surrounding four oxygens
of the tetrahedron, the requirement for the electronic neutrality for each of
the two linking O atoms is completely satisfied. In contrast, each of the
peripheral O atoms have a net excess of one negative charge. In order to
satisfy this each of these oxygens can be bonded with 3 neighbouring
bivalent cations in octahedral coordination (as shown above) or with four
bivalent cations in 8-fold coordination. In thepyroxenegroup bothpossibilities occur, each placing profound constraints on the way in which
the adjacent chains are located with respect to each other.
In double chain inosilicates (Si : 0 = 4 : 11) the chain forming elements give
rise to the basic formula: (Si4O11)n6n-
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
13/23
where the net excess of charges per 11 oxygens is equivalent to 6 negative
charges. The sheet forming elements in phyllosilicates (Si : 0 = 2 : 5) give
rise to the basic formula: Si2O5)n2n-
COMPOSITION OF GRANULAR SOILS
GRANULAR SOIL- are described as the type of soils where cohesion
between particles of the soil is absent or minimal. Working and compacting
on granular soils such assands and gravels is a really hard job to perform.
Due to their composition, water can enter or leave the voids with relative
ease. If voids in the sand are completely filled with water or are completely
dry there are no forces holding the sand particles.
BUILDING BLOCKS OF CLAY MINERALS
CLAY MINERAL
Clay minerals arehydrousaluminiumphyllosilicates,sometimes with
variable amounts ofiron,magnesium,alkali metals,alkaline earths,and
othercations.Clays form flat hexagonal sheets similar to themicas.
Clayminerals are commonweathering products (including weathering
offeldspar)and low temperaturehydrothermal alteration products. Clayminerals are very common in fine grainedsedimentary rocks such
asshale,mudstone,andsiltstone and in fine grained
metamorphicslate andphyllite.Clay minerals are usually (but not
necessarily) ultrafine-grained (normally considered to be less than 2
micrometres in size on standard particle size classifications) and so may
require special analytical techniques for their identification/study. These
includex-ray diffraction,electron diffractionmethods, various spectroscopic
methods such asMssbauer spectroscopy,infrared spectroscopy,and SEM-
EDS orautomated mineralogy solutions. These methods can be augmented
bypolarized light microscopy,a traditional technique establishing
fundamental occurrences or petrologic relationships. Clay minerals can be
classified as 1:1 or 2:1, this originates from the fact that they are
fundamentally built of tetrahedral silicate sheets and octahedral hydroxide
sheets, as described in the structure section below. A 1:1 clay would consist
http://geology.about.com/od/sediment_soil/a/aboutsand.htmhttp://en.wikipedia.org/wiki/Hydratehttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Silicate_minerals#Phyllosilicateshttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Alkali_metalhttp://en.wikipedia.org/wiki/Alkaline_earthhttp://en.wikipedia.org/wiki/Cationhttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Hydrothermalhttp://en.wikipedia.org/wiki/Sedimentary_rockhttp://en.wikipedia.org/wiki/Shalehttp://en.wikipedia.org/wiki/Mudstonehttp://en.wikipedia.org/wiki/Siltstonehttp://en.wikipedia.org/wiki/Slatehttp://en.wikipedia.org/wiki/Phyllitehttp://en.wikipedia.org/wiki/X-ray_diffractionhttp://en.wikipedia.org/wiki/Electron_diffractionhttp://en.wikipedia.org/wiki/M%C3%B6ssbauer_spectroscopyhttp://en.wikipedia.org/wiki/Infrared_spectroscopyhttp://en.wikipedia.org/wiki/Automated_mineralogyhttp://en.wikipedia.org/wiki/Petrographic_microscopehttp://en.wikipedia.org/wiki/Petrographic_microscopehttp://en.wikipedia.org/wiki/Automated_mineralogyhttp://en.wikipedia.org/wiki/Infrared_spectroscopyhttp://en.wikipedia.org/wiki/M%C3%B6ssbauer_spectroscopyhttp://en.wikipedia.org/wiki/Electron_diffractionhttp://en.wikipedia.org/wiki/X-ray_diffractionhttp://en.wikipedia.org/wiki/Phyllitehttp://en.wikipedia.org/wiki/Slatehttp://en.wikipedia.org/wiki/Siltstonehttp://en.wikipedia.org/wiki/Mudstonehttp://en.wikipedia.org/wiki/Shalehttp://en.wikipedia.org/wiki/Sedimentary_rockhttp://en.wikipedia.org/wiki/Hydrothermalhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Cationhttp://en.wikipedia.org/wiki/Alkaline_earthhttp://en.wikipedia.org/wiki/Alkali_metalhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Silicate_minerals#Phyllosilicateshttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Hydratehttp://geology.about.com/od/sediment_soil/a/aboutsand.htm -
8/12/2019 Castillon a#2 Soil Composition 2014-2015
14/23
of one tetrahedral sheet and one octahedral sheet, and examples would be
kaolinite and serpentine. A 2:1 clay consists of an octahedral sheet
sandwiched between two tetrahedral sheets, and examples are talc,
vermiculite and montmorillonite.
HISTORY
Knowledge of the nature of clay became better understood in the
1930s with advancements in x-ray diffraction technology necessary to
analyze the molecular nature of clay particles. Standardization in
terminology arose during this period as well with special attention given to
similar words that resulted in confusion such as sheet and plane.
STRUCTURE OF CLAY MINERALS
Like all phyllosilicates, clay minerals are characterised by two-
dimensional sheetsof corner sharing SiO4tetrahedra and/or
AlO4octahedra. The sheet units have the chemical composition (Al,Si)3O4.
Each silica tetrahedron shares 3 of its vertex oxygen atoms with other
tetrahedra forming a hexagonal array in two-dimensions. The fourth vertex
is not shared with another tetrahedron and all of the tetrahedra "point" in
the same direction; i.e. all of the unshared vertices are on the same side of
the sheet. In clays, the tetrahedral sheets are always bonded to octahedral
sheets formed from small cations, such as aluminium or magnesium, and
coordinated by six oxygen atoms. The unshared vertex from the tetrahedral
sheet also forms part of one side of the octahedral sheet, but an additional
oxygen atom is located above the gap in the tetrahedral sheet at the center
of the six tetrahedral. This oxygen atom is bonded to a hydrogen atom
forming an OH group in the clay structure. Clays can be categorized
depending on the way that tetrahedral and octahedral sheets are packagedinto layers. If there is only one tetrahedral and one octahedral group in
each layer the clay is known as a 1:1 clay. The alternative, known as a 2:1
clay, has two tetrahedral sheets with the unshared vertex of each sheet
pointing towards each other and forming each side of the octahedral sheet.
Bonding between the tetrahedral and octahedral sheets requires that the
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
15/23
tetrahedral sheet becomes corrugated or twisted; causing ditrigonal
distortion to the hexagonal array, and the octahedral sheet is flattened.
This minimizes the overall bond-valence distortions of the crystallite.
Depending on the composition of the tetrahedral and octahedral sheets,
the layer will have no charge, or will have a net negative charge. If thelayers are charged this charge is balanced by interlayer cations such as
Na+or K
+. In each case the interlayer can also contain water. The crystal
structure is formed from a stack of layers interspaced with the interlayers.
TYPES OF BONDS
Clay Minerals:1. The Crystalline minerals whose surface activity is high are called clay
minerals.
2. The behavior of the fine grained soils depends to a large extent on
the nature and characteristics of the minerals present.
3. Clay Mineralogy is the science dealing with the structure of the clay
minerals on microscopic, molecular and atomic scale. It also includes
the study of the mineralogical composition and electrical propertiesof the clay particles.
Primary Valence Bonds:
Primary Valence bonds hold together the atoms of molecule. These
are of two types
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
16/23
Ionic Bond:
In an atom the electrons carrying a negative charge revolve about the
nucleus. Some elements have an excess or a deficiency of the electrons in
the outer shell one atom joins another atom by adding some of the
electrons to its outer shell or by losing some of electrons from its outershell.
C ovalent Bond:
This type of bond develops between two atoms by sharing of
electrons in their outer shell.
Two atoms, each lacking one electron, may combine by sharing of
pair of electrons.
Primary valence bonds are very strong. These bonds do not break innormal soil engineering applications. Therefore, primary valance bonds
are not much relevance in soil engineering.
Hydrogen Bond:
The hydrogen bond has only one electron. The number of electrons
required to fill the first shell is The atom can be considered either as a
cation (with one excess electron) or an anion (with one electron
deficiency). The bond between the hydrogen cation (H+ ) and anions of two
atoms of another element is called Hydrogen Bond.
Hydrogen bond is considerably weaker than primary valence bond.
However, it is fairly strong and cannot be broken during normal soil
engineering problems.
Secondary Valence Bonds:
Secondary valence bonds are intermolecular bonds which develop
between atoms in one molecule to atoms in another molecule. A molecule
is electrically neutral. i.e., it has no charge. However the construction of themolecule may be such that centres of the negative and positive charges do
not exactly coincide. The molecule may behave like a bar magnet, with two
electrical dipoles. Consequently, an electrical moment is developed inside
the molecule; a molecule with such a structure is called a dipole. In nature,
two dipolar molecules orient themselves in such a way that net attraction
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
17/23
occurs. The attractive forces so developed are known as Vander Waal
Forces. (After Vander Waal who postulated the existence of a common
attractive forces between molecules of all matters in 1873)
COMMON CLAY MINERALS WITH TWO SHEETS PER LAYER
THE BASIC STRUCTURE
KAOLINITE
This is the most common mineral of the kaolin group. The building
blocks of gibbsite and silica sheets are arranged as shown in Fig. 2.4 to give
the structure of the kaolinite layer. The structure is composed of a single
tetrahedral sheet and a single alumina octahedral sheet combined in units
so that the tips of the silica tetrahedrons and one of the layers of the
octahedral sheet form a common layer. All the tips of the silica
tetrahedrons point in the same direction and towards the center of the unit
made of the silica and octahedral sheets. This gives rise to strong ionic
bonds between the silica and gibbsite sheets. The thickness of the layer is
about 7 A (one angstrom = 10~8 cm) thick. The kaolinite mineral is formed
by stacking the layers one above the other with the base of the silica sheet
bonding to hydroxyls of the gibbsite sheet by hydrogen bonding. Since
hydrogen bonds are comparatively strong, the kaolinite crystals consist of
many sheet stackings that are difficult to dislodge. The mineral is therefore,
stable, and water cannot enter between the sheets to expand the unit cells.
The lateral dimensions of kaolinite particles range from 1000 to 20,000 A
and the thickness varies from 100 to 1000 A. In the kaolinite mineral there
is a very small amount of isomorphous substitution.
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
18/23
DICRITE AND NACRITE
Generally differ only in the stacking arrangements which for, for
engineering purpose, are irrelevant.
HALLOYSITE
Halloysite minerals are made up of successive layers with the same
structural composition as those composing kaolinite. In this case, however,
the successive units are randomly packed and may be separated by a single
molecular layer of water. The dehydration of the interlayers by the removal
of the water molecules leads to changes in the properties of the mineral.
An important structural feature of halloysite is that the particles appear to
take tubular forms as opposed to the platy shape of kaolinite.
G. COMMON CLAY MINERALS WITH THREE SHEETS PER LAYER
MICA
The prototype of the three-layer minerals are the primary minerals of
the mica group
MONTMORILLONITE
Montmorillonite is the most common mineral of the montmorillonite
group. The structural arrangement of this mineral is composed of two silica
tetrahedral sheets with a central alumina octahedral sheet. All the tips of
the tetrahedra point in the same direction and toward the center of the
unit. The silica and gibbsite sheets are combined in such a way that the tips
of the tetrahedrons of each sheet and one of the hydroxyl layers of the
octahedral sheet form a common layer. The atoms common to both thesilica and gibbsite layer become oxygen instead of hydroxyls. The thickness
of the silica-gibbsite-silica unit is about 10 A (Fig. 2.5). In stacking these
combined units one above the other, oxygen layers of each unit are
adjacent to oxygen of the neighboring units with a consequence that there
is a very weak bond and an excellent cleavage between them. Water can
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
19/23
enter between the sheets, causing them to expand significantly and thus
the structure can break into 10 A thick structural units. Soils containing a
considerable amount of montmorillonite minerals will exhibit high swelling
and shrinkage characteristics. The lateral dimensions of montmorillonite
particles range from 1000 to 5000 A with thickness varying from 10 to 50 A.Bentonite clay belongs to the montmorillonite group. In montmorillonite,
there is isomorphous substitution of magnesium and iron for aluminum.
ILLITE
The basic structural unit of illite is similar to that of montmorillonite
except that some of the silicons are always replaced by aluminum atoms
and the resultant charge deficiency is balanced by potassium ions. The
potassium ions occur between unit layers. The bonds with thenonexchangeable K+ ions are weaker than the hydrogen bonds, but
stronger than the water bond of montmorillonite. Illite, therefore, does not
swell as much in the presence of water as does montmorillonite. The lateral
dimensions of illite clay particles are about the same as those of
montmorillonite, 1000 to 5000 A, but the thickness of illite particles is
greater than that of montmorillonite particles, 50 to 500 A.
VERMICULITE
Is a hydrous, silicate mineral that is classified as a phyllosilicate and
that expands greatly when heated. Exfoliation occurs when the mineral is
heated sufficiently, and the effect is routinely produced in commercial
furnaces. Is formed by weathering or hydrothermal alteration of biotite or
phlogopite.
CHLORITE
Is very common, and is often an uninteresting green mineral coatingthe surface of more important minerals. However, there are some crystal
forms and varieties that are attractive on their own right. Chlorite also
forms as inclusions within other minerals, especially Quartz, where it makes
the host mineral green and may even cause phantom growths.
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
20/23
RELATIONSHIP BETWEEN SOIL COMPOSITION AND ENGINEERING
PROPERTIES OF SOIL
RELATIONSHIP OF GRAINED SOIL AND ENGINEERING PROPERTIES OF SOIL
Coarse-grained soils have good load-bearing capacities and good
drainage qualities, and their strength and volume change characteristics are
not significantly affected by change in moisture conditions under static
loading. They are practically incompressible when dense, but significant
volume changes can occur when they are loose. Vibrations accentuate
volume changes in loose, coarse-grained soils by rearranging the soil fabric
into a dense configuration. Fine-grained soils have poor load-bearing
capacities compared with coarse-grained soils. Fine grained soils are
practically impermeable, change volume and strength with variations inmoisture conditions, and are susceptible to frost. The engineering
properties of coarse-grained soils are controlled mainly by the grain size of
the particles and their structural arrangement. The engineering properties
of fine-grained soils are controlled by mineralogical factors rather than
grain size. Thin layers of fine-grained soils, even within thick deposits of
coarse-grained soils, have been responsible for many geotechnical failures,
and therefore you need to pay special attention to fi ne-grained soils. In
this book, we will deal with soil as a construction and a foundation
material. We will not consider soils containing organic material or theparent material of soils, rock. We will label our soils as engineering soils to
distinguish our consideration of soils from that of geologists, agronomists,
and soil scientists, who have additional interests in soils not related to
construction activities.
THE ESSENTIAL POINTS ARE:
1. Fine-grained soils have much larger surface areas than coarse-
grained soils and are responsible for the major physical andmechanical differences between coarse-grained and fine grained
soils.
2. The engineering properties of fine-grained soils depend mainly on
mineralogical factors.
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
21/23
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
22/23
7. Two coefficientsthe uniformity coefficient and the coefficient of
curvatureare used to characterize the particle size distribution.
Poorly graded soils have uniformity coefficients, 4 and steep
gradation curves. Well-graded soils have uniformity coefficients .4,
coefficients of curvature between 1 and 3, and flat gradation curves.Gap-graded soils have coefficients of curvature ,1 or .3, and one or
more humps on the gradation curves.
PERMEABILITY
The permeability is a measure of the rate at which fluids passes
through a porous medium.
COMPRESSIBILTYIf the normal stress in the soil is increased, and the pore fluid is free
to drain from it, the particles are forced together.
If the stress increment is removed, and the pore fluid is free to return
to the soil, some expansion takes place as the adsorbed layers return to
their original thickness. However, particles which have been forced into
contact, or which have been rearranged by rotation, do not return to their
original positions. Thus, much of the volume change is irreversible.
The compressibility and swelling properties also depend on the
nature of clay minerals, and the nature and concentration of the cations in
the adsorbed layers.
Where clays contain considerable quantity of montmorillonite, large
volume changes accompany changes of stress, as a result of the changes in
the thickness of the water layers within the crystals.
-
8/12/2019 Castillon a#2 Soil Composition 2014-2015
23/23
REFERENCE
Soil Mechanics and Foundations 3rd Ed., C. R. Scott
Soil Mechanics and Foundations 3rd ed. - M. Budhu (Wiley, 2010) BBS
Geotechnical Engineering Principles and Practices of Soil Mechanics and Foundation Engineering, V.N.S. Murthy
http://elearning.vtu.ac.in/11/enotes/geotechengg/Unit%203-NH.
http://construction.about.com/od/Earthwork/a/Compacting-Granular-Soils.htm
http://en.wikipedia.org/wiki/Mineralogy#History
http://en.wikipedia.org/wiki/Specific_gravity
http://en.wikipedia.org/wiki/Transparency_and_translucency
http://en.wikipedia.org/wiki/Clay_minerals
http://en.wikipedia.org/wiki/Streak_(mineralogy)
http://en.wikipedia.org/wiki/Lustre_(mineralogy)
http://en.wikipedia.org/wiki/Cleavage_(crystal)
http://en.wikipedia.org/wiki/Mineralogy#History
http://en.wikipedia.org/wiki/Crystal_structure
http://en.wikipedia.org/wiki/Crystal_habit
http://elearning.vtu.ac.in/11/enotes/geotechengg/Unit%203-NHhttp://construction.about.com/od/Earthwork/a/Compacting-Granular-Soils.htmhttp://en.wikipedia.org/wiki/Mineralogy#Historyhttp://en.wikipedia.org/wiki/Specific_gravityhttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Streak_(mineralogy)http://en.wikipedia.org/wiki/Lustre_(mineralogy)http://en.wikipedia.org/wiki/Cleavage_(crystal)http://en.wikipedia.org/wiki/Mineralogy#Historyhttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Crystal_habithttp://en.wikipedia.org/wiki/Crystal_habithttp://en.wikipedia.org/wiki/Crystal_structurehttp://en.wikipedia.org/wiki/Mineralogy#Historyhttp://en.wikipedia.org/wiki/Cleavage_(crystal)http://en.wikipedia.org/wiki/Lustre_(mineralogy)http://en.wikipedia.org/wiki/Streak_(mineralogy)http://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Specific_gravityhttp://en.wikipedia.org/wiki/Mineralogy#Historyhttp://construction.about.com/od/Earthwork/a/Compacting-Granular-Soils.htmhttp://elearning.vtu.ac.in/11/enotes/geotechengg/Unit%203-NH