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POLITEKNIK SULTAN ABDUL HALIMMU’ADZAM SHAH

BANDAR DARULAMAN, 06000 JITRA, KEDAH

C3008

GEOTECHNIC

PROCESS OF IMPROVING SOILCHARACTERISTIC

NAME : NUR SHAHIDAH BINTI ABU BAKARREG NUMBER : 03DKA09 F1039

COURSE/SEMESTER : DKA3A

DATE SUBMIT : 20 OCTOBER 2010

LECTURER : EN NOR HAZIZI BIN ABD MUTHALIB



INTRODUCTION OF SOIL

Soil is a natural body consisting of layers (soil horizons)of mineral constituents of variable thicknesses, which differfrom the parent materials in their morphological, physical,

chemical, and mineralogical characteristics . It is composedof particles of broken rock that have been altered by

chemical and environmental processes thatinclude weathering and erosion. Soil differs from its parent

rock due to interactions betweenthe lithosphere, hydrosphere, atmosphere, and

the biosphere. It is a mixture of mineral and organicconstituents that are in solid, gaseous and aqueous states.

INTRODUCTION OF SOIL



Soil particles pack loosely, forming a soil structure filled withpore spaces. These pores contain soil solution (liquid) and

air (gas). Accordingly, soils are often treated as athree state system. Most soils have a density between 1

and 2 g/cm³. Soil is also known as earth: it is the substancefrom which our planet takes its name. Little of the soil

composition of planet Earth is older than the Tertiary andmost no older than the Pleistocene . In engineering, soil is

referred to as regolith, or loose rock material.

INTRODUCTION TO SOIL



The weathering of bedrock produces the parent material fromwhich soils form. An example of soil development from bare

rock occurs on recent lava flows in warm regions underheavy and very frequent rainfall. In such climates, plantsbecome established very quickly on basaltic lava, even

though there is very little organic material. The plants aresupported by the porous rock as it is filled with nutrient-

bearing water which carries, for example, dissolved mineralsand guano.

SOIL FORMING FACTORS



The developing plant roots, themselves or associatedwith mycorrhizal fungi, gradually break up the porous lavaand organic matter soon accumulates. But even before itdoes, the predominantly porous broken lava in which the

plant roots grow can be considered a soil. How the soil "life"cycle proceeds is influenced by at least five classic soil

forming factors that are dynamically intertwined in shapingthe way soil is developed, they include: parent material,

regional climate, topography, biotic potential and the

passage of time.

SOIL FORMING FACTORS



PARENT MATERIAL

The material from which soils form is called parent material. It

includes: weathered primary bedrock; secondary materialtransported from other locations,

e.g. colluvium and alluvium; deposits that are alreadypresent but mixed or altered in other ways - old soil

formations, organic material including peat or alpine humus;and anthropogenic materials, like landfill or mine

waste. Few soils form directly from the breakdown of theunderlying rocks they develop on. These soils are often

called “residual soils”, and have the same general

chemistry as their parent rocks. Most soils derive frommaterials that have been transported from other locations

by wind, water and gravity.

CHARACTERISTIC OF SOIL




Some of these materials may have moved many miles or only a

few feet. Windblown material called loess is common inthe Midwest of North America and in Central Asia and other

locations. Glacial till is a component of many soils in thenorthern and southern latitudes and those formed near large

mountains; till is the product of glacial ice moving over theground. The ice can break rock and larger stones intosmaller pieces, it also can sort material into different sizes.As glacial ice melts, the melt water also moves and sortsmaterial, and deposits it varying distances from its origin.

The deeper sections of the soil profile may have materialsthat are relatively unchanged from when they were

deposited by water, ice or wind.




Weathering is the first stage in the transforming of parent

material into soil material. In soils forming from bedrock, athick layer of weathered material called saprolite may form.Saprolite is the result of weathering processes that include:

hydrolysis (the replacement of a mineral‟s cations with

hydrogen ions), chelation from organic compounds,hydration (the absorption of water by minerals), solution ofminerals by water, and physical processes that include

freezing and thawing or wetting and drying.Themineralogical and chemical composition of the primary

bedrock material, plus physical features, including grain sizeand degree of consolidation, plus the rate and type ofweathering, transforms it into different soil materials.



CLIMATE

Soil formation greatly depends on the climate, and soils from

different climate zones show distinctive characteristics .Temperature and moisture affect weathering and leaching.Wind moves sand and other particles, especially in aridregions where there is little plant cover. The type and

amount of precipitation influence soil formation by affecting

the movement of ions and particles through the soil, aidingin the development of different soil profiles. Seasonal anddaily temperature fluctuations affect the effectiveness ofwater in weathering parent rock material and affect soil

dynamics. The cycle of freezing and thawing is an effectivemechanism to break up rocks and other consolidatedmaterials. Temperature and precipitation rates affect

biological activity, rates of chemical reactions and types of

vegetation cover.CHARACTERISTIC OF SOIL



BIOLOGICAL FACTORSPlants, animals, fungi, bacteria and humans affect soil formation

(see soil biomantle and stonelayer). Animals and micro-

organisms mix soils to form burrows and pores allowing moisture andgases to seep into deeper layers. In the same way, plant roots openchannels in the soils, especially plants with deep taproots which canpenetrate many meters through the different soil layers to bring up

nutrients from deeper in the soil. Plants with fibrous roots that spreadout near the soil surface, have roots that are easily decomposed,

adding organic matter. Micro-organisms, including fungi and bacteria,affect chemical exchanges between roots and soil and act as a

reserve of nutrients. Humans can impact soil formation by removing

vegetation cover; this removal promotes erosion. They can also mixthe different soil layers, restarting the soil formation process as less-

weathered material is mixed with and diluting the more developedupper layers. Some soils may contain up to one million species ofmicrobes per gram, most of those species being unknown, making

soil the most abundant ecosystem on Earth.CHARACTERISTIC OF SOIL



CHAACTERISTIC OF SOIL

Vegetation impacts soils in numerous ways. It can preventerosion from rain or surface runoff. It shades soils, keeping

them cooler and slowing evaporation of soil moisture, or itcan cause soils to dry out by transpiration. Plants can formnew chemicals that break down or build up soil particles.

Vegetation depends on climate, land form topography andbiological factors. Soil factors such as soil density, depth,chemistry, pH, temperature and moisture greatly affect the

type of plants that can grow in a given location. Dead plants,dropped leaves and stems of plants fall to the surface of the

soil and decompose. There, organisms feed on them and mix

the organic material with the upper soil layers; these organiccompounds become part of the soil formation process,

ultimately shaping the type of soil formed.



TIME

Time is a factor in the interactions of all the above factors asthey develop soil. Over time, soils evolve features

dependent on the other forming factors, and soil formationis a time-responsive process dependent on how the otherfactors interplay with each other. Soil is always changing.

For example, recently-deposited material from a flood

exhibits no soil development because there has not beenenough time for soil-forming activities. The soil surface is

buried, and the formation process begins again for this soil.The long periods over which change occurs and its multiple

influences mean that simple soils are rare, resulting in theformation of soil horizons. While soil can achieve relativestability in properties for extended periods, the soil life cycleultimately ends in soil conditions that leave it vulnerable to

erosion.CHARACTERISTIC OF SOIL




Despite the inevitability of soil retrogression and degradation,most soil cycles are long and productive.

Soil-forming factors continue to affect soils during theirexistence, even on “stable” landscapes that are long-

enduring, some for millions of years. Materials are depositedon top and materials are blown or washed away from the

surface. With additions, removals and alterations, soils arealways subject to new conditions. Whether these are slow or

rapid changes depend on climate, landscape position andbiological activity.



CHARACTERISTICS OF SOIL SUITABLE FORCIVIL ENGINEERING WORKS

The term „Soil‟ means different things to different people:

To a geologist it represents the products of past surfaceprocesses. To a pedologist it represents currentlyoccurring physical and chemical processes. To an

engineer it is a material that can be:

Built on: foundations to buildings, bridges.Built in: tunnels, culverts, basements.Built with: roads, runways, embankments, dams.Supported: retaining walls, quays.

CHARACTERISTIC OF SOIL SUITABLE FORCIVIL ENGINEERING WORK



Soils may be described in different ways by differentpeople for their different purposes. Engineers'

descriptions give engineering terms that will conveysome sense of a soil's current state and probable

susceptibility to future changes (e.g. in loading, drainage,structure, surface level).

Engineers are primarily interested in a soil's mechanicalproperties: Strength, Stiffness, Permeability. Thesedepend primarily on the nature of the soil grains, the

current stress, the water content and unit weight.




I. Strength - In very simple terms, the strength of soil isthe maximum shear stress (tf) it can sustain, or the

shear stress acting on a shear slip surface along which itis failing. There are three distinct strengths: peak, critical

(or ultimate) and residual. Shearing may be simple ordirect.

II. Stiffness - Susceptibility to distortion or volume changeunder load.

III. Permeability - The property which allows the flow ofwater through a soil. The constant average discharge

velocity (v) of water passing through soil when thehydraulic gradient (i) is 1.0; defined by Darcy‟s law: v =

k.i




SLOPE FAILURE

A slope failure isphenomenon that a slopecollapses abruptly due to

weakened self-retainabilityof the earth under the

influence of a rainfall or an

earthquake. Because ofsudden collapse of slope,

many people fail to escapefrom it if it occurs near a

residential area,thusresulting in a higherrate of fatalities.

TYPE OF SOIL FAILURE



RETAINING WALL WORKS

Concrete retaining walls are built on the lower

part of a slope to directly suppress a collapseof that part and also to check coming-down

collapsed soil and stop it before houses.




SOLDIER PILES AND LAGGING WORKS

Steel piles are driven into a slope to restrain thecollapse of the surface soil layer. Lagging is placedbetween piles to prevent downward movement of

eroded soil. This construction method can beapplied not to destroy existing vegetation.




GRATING CRIB WORKS

Concrete frames are laid on a slope, within whichplants grow to protect the slope from weathering

and erosion. It is also possible to directly suppressslope collapse by using the frames in combination

with ground anchors, etc., or to allow treesremaining on the slope to be retained by adjusting

the arrangement of the frames.




FAILURE DURING EXCAVATION


Tension cracks can cause sliding, sluffing, or toppling

Unsupported excavation can cause bulging in thevertical face

Use support systems to keep nearby buildings, wallsstable

• Shoring

• Bracing

• Underpinning

SHALLOW FAILURE



SHALLOW FAILURE

General shear failure

• when the pressure is raised, plastic equilibrium isreached, the soil around the base gradually spreaddownward and out.

• plastic equilibrium in the soil is fully formed on thesurface failed

• perlambungan surface occurs on both sides of thebase

Local Shear Failure

• large compression occurs in the soil under thefoundation and just apply some plastic equilibrium.

• a slight perlambungan at the soil surface andcompaction at the bottom of the base

• This situation can cause the sediments at the base.TYPE OF SOIL FAILURE



Punching shear failure

• occurs when there is compression of the soil at the baseand does not apply perlambungan land on the ground.

• This situation cause the deposition at the foundation.


Deep foundation



Deep foundation

Foundation failure caused by many factors, they are:

Evaporation Hot and dry conditions and extended periods ofdrought will cause soils to pull away from foundations.Settlement usually occurs showing cracks throughout

the structure in concrete and drywall. Transpiration

The removal of moisture from the soils caused byplant and tree roots around or under structures will

cause soil shrinkage and settlement of yourfoundation.

Poor Soil condition Expansion and/or contraction of poor soils contributeto foundation failures.




Poor Soil Preparation In most cases, cut and fill areas are improperlycompacted causing settlement of the structure.

Poor Foundation Construction Insufficient steel in the concrete could contributeto movement in foundations.

Plumbing Water from leaky plumbing is often a majorcontributor to foundation problems. For moreinformation on water problems, click here.

Drainage

Water that is not drained away from structures willlead to excess mosture build up. Moisture couldthen erode soils and cause settling of structures.




TECHNIC USE IN IMPROVINGSOIL CHARACTERISTIC

COMPACTIONCompaction (geology) refers to the process by which

a sediment progressively loses its porosity due to the effects of

loading. This forms part of the process of lithification . When alayer of sediment is originally deposited, it contains an open

framework of particles with the pore space being usually filledwith water. As more sediment is deposited above the layer, the

effect of the increased loading is to increase the particle-to-particle stresses resulting in porosity reduction primarily througha more efficient packing of the particles and to a lesser extentthrough elastic compression and pressure solution. The initial

porosity of a sediment depends on its lithology

. Mudstones start with porosities of >60%, sandstones typically~40% and carbonates sometimes as high as 70%. Results

from hydrocarbon exploration wells show clear porosityreduction trends with depth.



In sediments compacted under self-weight, especially insedimentary basins ,the porosity profiles often show an

exponential decrease, called Athy's law as first shown by

Athy in 1930. A mathematical analytical solution wasobtained by Fowler and Yang to show the theoretical basis

for Athy's law. This behaviour can be easily observed inexperiments and used as a good approximation to many

real data.




CONSOLIDATION

Consolidation is a process by which soils decrease in volume.It occurs when stress is applied to a soil that causes thesoil particles to pack together more tightly, therefore

reducing its bulk volume. When this occurs in a soil that issaturated with water, water will be squeezed out of the soil.

The magnitude of consolidation can be predicted by manydifferent methods. In the Classical Method, developed

by Karl von Terzaghi, soils are tested with an oedometertest to determine their compression index. This can be

used to predict the amount of consolidation.





When stress is removed from a consolidated soil, the soil willrebound, regaining some of the volume it had lost in the

consolidation process. If the stress is reapplied, the soil will

consolidate again along a recompression curve, defined by therecompression index. The soil which had its load removed isconsidered to be overconsolidated . This is the case for soils

which have previously had glaciers on them. The highest stress

that it has been subjected to is termed the preconsolidation stress . The over consolidation ratio or OCR is defined as the

highest stress experienced divided by the current stress. A soilwhich is currently experiencing its highest stress is said to

be normally consolidated and to have an OCR of one. A soilcould be considered underconsolidated immediately after a

new load is applied but before the excess pore water pressurehas had time to dissipate.




The time for consolidation to occur can be predicted.Sometimes consolidation can take years. This is especiallytrue in saturated clays because their hydraulic conductivity

is extremely low, and this causes the water to take anexceptionally long time to drain out of the soil. While

drainage is occurring, the pore water pressure is greaterthan normal because it is carrying part of the applied stress

(as opposed to the soil particles).



CONSOLIDATION ANALYSIS

SPRING ANALOGY

The process of consolidation is often explained with anidealized system composed of a spring, a container with a

hole in its cover, and water. In this system, the springrepresents the compressibility or the structure itself of thesoil, and the water which fills the container represents the

pore water in the soil.





• The container is completely filled with water, and the hole is

closed. (Fully saturated soil)• A load is applied onto the cover, while the hole is still

unopened. At this stage, only the water resists the appliedload. (Development of excess pore water pressure)

• As soon as the hole is opened, water starts to drain outthrough the hole and the spring shortens. (Drainage ofexcess pore water pressure)

• After some time, the drainage of water no longer occurs.Now, the spring alone resists the applied load. (Fulldissipation of excess pore water pressure. End ofconsolidation)

PRIMARY CONSOLIDATION




PRIMARY CONSOLIDATION

This method assumes consolidation occurs in only one-dimension. Laboratory data is used to construct a plot

of strain or void ratio versus effective stress where the effectivestress axis is on a logarithmic scale. The plot's slope is thecompression index or recompession index. The equation forconsolidation settlement of a normally consolidated soil can

then be determined to be:

• where

• δc is the settlement due to consolidation.

• Cc is the compression index.

• e0 is the initial void ratio.

• H is the height of the soil.

• σzf is the final vertical stress.

• σz0 is the initial vertical stress.




Cc can be replaced by Cr (the recompression index) for use inoverconsolidated soils where the final effective stress is

less than the preconsolidation stress. When the finaleffective stress is greater than the preconsolidation stress,the two equations must be used in combination to model

both the recompression portion and the virgin compression

portion of the consolidation process, as follows:

• where σzc is the preconsolidation stress of the soil




SECONDARY CONSOLIDATION

Secondary consolidation is the compression of soil that takesplace after primary consolidation. Secondary consolidation

is caused by creep, viscous behavior of the clay-watersystem, compression of organic matter, and other

processes. In sand, settlement caused by secondarycompression is negligible, but in peat, it is very significant .

Secondary consolidation is given by the formula

Where• H0 is the height of the consolidating medium

• e0 is the initial void ratio

• Ca is the secondary compression index



GEOSYNTHETICS

Geosynthetics is the term used to describe a range of generallypolymeric products used to solve civil engineering problems.

The term is generally regarded to encompass eight mainproduct

categories: geotextiles, geogrids, geonets, geomembranes, g

eosynthetic clay liners, geofoam, geocells (cellularconfinement) and geocomposites. The polymeric nature of

the products makes them suitable for use in the groundwhere high levels of durability are required. Properly

formulated, however, they can also be used in exposedapplications..

GEOSYNTHETICS IN WORK TO IMPROVINGSOIL CHARACTERISTIC



Geosynthetics are available in a wide range of forms andmaterials, each to suit a slightly different end use. These

products have a wide range of applications and arecurrently used in many civil, geotechnical, transportation,

geoenvironmental, hydraulic, andprivate development applications

including roads, airfields,railroads, embankments, retaining structures, reservoirs, canals, dams, erosioncontrol, sediment control, landfill liners, landfill

covers, mining, aquaculture and agriculture.




GEOTEXTILE



GEOTEXTILE

Geotextiles are permeable fabrics which, when used inassociation with soil, have the ability to separate, filter,

reinforce, protect, or drain. Typically madefrom polypropylene or polyester, geotextile fabrics come in

three basic forms: woven (looks like mail bag sacking),needle punched (looks like felt), or heat bonded (looks like

ironed felt).Geotextile composites have been introduced and products

such as geogrids and meshes have been developed.Overall, these materials are referred to

as geosynthetics and each configuration—-geonets,geogrids and others—-can yield benefits

in geotechnical and environmental engineering design.

GEOSYNTHETICS IN WORK TO IMPROVING

SOIL CHARACTERISTIC



APPLICATION OF GEOTEXTILE

Geotextiles and related products have many applications andcurrently support many civil engineering applications including

roads, airfields, railroads, embankments, retainingstructures, reservoirs, canals, dams, bank protection, coastal

engineering and construction site silt fences. Usuallygeotextiles are placed at the tension surface to strengthen the

soil. Geotextiles are also used for sand dune armoring toprotect upland coastal property from storm surge, wave action

and flooding. A large sand-filled container (SFC) within the

dune system prevents storm erosion from proceeding beyondthe SFC. Using a sloped unit rather than a single tube

eliminates damaging scour.




Erosion control manuals comment on the effectiveness of

sloped, stepped shapes in mitigating shoreline erosiondamage from storms. Geotextile sand-filled units provide a

"soft" armoring solution for upland property protection.Geotextiles are used as matting to stabilize flow in stream

channels and swales.Geotextiles can improve soil strength at a lower cost than

conventional soil nailing. In addition, geotextiles allowplanting on steep slopes, further securing the slope.




Geotextiles have been used to protect the

fossil hominid footprintsof Laetoli in Tanzania from erosion, rain, and tree roots.

In building demolition, geotextile fabrics in combination withsteel wire fencing can contain explosive debris.

Coir (coconut fiber) geotextiles are a popular solution forerosion control, slope stabilization and bioengineering,due to the fabric's substantial mechanical strength.Coir

geotextiles last approximately 3 to 5 years depending on

the fabric weight. The product degrades into humus,enriching the soil.[


GEOMEMBRANE



GEOMEMBRANE

Geomembranes are a kind of geosynthetic material. Theyare impermeable membranes used widely as cut-offs and

liners. Until recent years, geomembranes were used mostlyas canal and pond liners. One of the largest currentapplications is at landfill sites for the containment of

hazardous or municipal wastes and their leachates. In manyof these applications geomembranes are employed withgeotextile or mesh underliners which reinforce or protectthe more flexible geomembrane whilst also acting as an

escape route for gases and leachates generated in certainwastes.


PHYSICAL PROPERTIES OF



PHYSICAL PROPERTIES OFGEOMEMBRANE

The physical material properties of geomembranes includethickness, density, water vapor transmission, solvent vapor

transmission, and melt flow index. The thickness can be

measured by using a standard thickness test in which athickness gauge under twenty kPa is applied for five

seconds. All densities for PVC and polyethylene (PE) areless than one, so it is reasonable find the mass per unit

volume instead of the density for most geomembranes.




The water vapor transmission is the amount of water thatcan permeate the geomembrane. The solvent vapor

index is the measurement of the flow of vapors besideswater vapor through the geomembrane liner. The melt

flow index is the measurement of the fluidity of themolten geomembrane. It is measured by heating thepolymer until it is liquid. Once it has been heated, it isthen pushed through a small orifice under a constant

load for ten minutes. The higher the melt flow index is,

the lower the density.


SOIL CHARACTERISTIC

CHARACTERISTIC OF GEOMEMBRANCE



CHARACTERISTIC OF GEOMEMBRANCE

Each type of geomembrane material has different

characteristics which affect installation procedures, lifespanand performance. For example, PVC geomembranes arevery flexible and as a result can conform to uneven

surfaces without becoming punctured. EPDM rubber ishighly flexible and has excellent UV and weathering

characteristics, but is not suitable for use in long termcontact with oils and hydrocarbons. LDPE, on the otherhand, is very susceptible to UV radiation, and therefore

should not be used in applications where it will be exposed

or else it will become brittle and fragile. HDPE hasexcellent chemical resistance, but is inflexible and suffersfrom environmental stress cracking and thermal stresses.


SOIL CHARACTERISTIC

GEOGRID



GEOGRID

The development of methods of preparing relatively rigid

polymeric materials by tensile drawing, in a sense "coldworking," raised the possibility that such materials couldbe used in the reinforcement of soils for walls, steep

slopes, roadway bases and foundation soils. Used assuch, the major function of the resulting geogrids is in

the area of reinforcement. This area, as with many othergeosynthetics, is very active, with a number of different

products, materials, configurations, etc., making uptoday's geogrid market. The key feature of all geogrids is

that the openings between the adjacent sets oflongitudinal and transverse ribs, called “apertures,” are

large enough to allow for soil strike-through from oneside of the geogrid to the other.


SOIL CHARACTERISTIC



The ribs of some geogrids are often quite stiff compared tothe fibers of geotextiles. As will be discussed later, not

only is rib strength important, but junction strength is alsoimportant. The for this is that in anchorage situations the

soil strike-through within the apertures bears against thetransverse ribs, which transmits the load to the

longitudinal ribs via the junctions. The junctions are, ofcourse, where the longitudinal and transverse ribs meetand are connected. They are sometimes called “nodes”.


SOIL CHARACTERISTIC



Currently there are three categories of geogrids. The first,

and original, geogrids (called unitized or homogeneoustypes) were invented by Dr Frank Brian Mercer in theUnited Kingdom at Netlon, Ltd., and were brought in1982 to North America by the Tensar Corporation. A

conference in 1984 was helpful in bringing geogrids tothe engineering design community. A similar type of

drawn geogrid which originated in Italy by Tenax is alsoavailable, as are products by new manufacturers in Asia.

The second category of geogrids are more flexible,textile-like geogrids using bundles of polyethylenecoated polyester fibres as the reinforcing component.


SOIL CHARACTERISTIC



They were first developed by ICI Linear Composites LTD in

the United Kingdom around 1980. This led to thedevelopment of polyester yarn geogrids made on textile

weaving machinery. In this process hundreds ofcontinuous fibers are gathered together to form yarnswhich are woven into longitudinal and transverse ribswith large open spaces between. The cross-overs are

joined by knitting or intertwining before the entire unit isprotected by a subsequent coating. Bitumen, latex or

PVC are the usual coating

materials. Geosynthetics within this group aremanufactured by many companies having various

trademarked products.


SOIL CHARACTERISTIC



There are possibly as many as 25 companies

manufacturing coated yarn-type polyester geogrids on aworldwide basis. The third category of geogrids are

made by laser or ultrasonically bonding togetherpolyester or polypropylene rods or straps in a gridlike

pattern. Two manufacturers currently make suchgeogrids.

The geogrid area is extremely active not only inmanufacturing new products, but also in providingsignificant technical information to aid the design

engineer.


SOIL CHARACTERISTIC



GEONET

Geonets, called "geospacers" by some, constitute anotherspecialized segment within the geosynthetics area. They

are formed by continuous extrusion of parallel sets of

polymeric ribs at acute angles to one another. When theribs are opened, relatively large apertures are formed into

a netlike configuration. Their design function iscompletelyin the in-plane drainage area where they are

used to convey all types of liquids.


SOIL CHARACTERISTIC



GEOCOMPOSITE



GEOCOMPOSITE

The basic philosophy behind geocomposite materials is tocombine the best features of different materials in such a

way that specific applications are addressed in the optimalmanner and at minimum cost. Thus, the benefit/cost ratio is

maximized. Such geocomposites will generally begeosynthetic materials, but not always. In some cases it

may be more advantageous to use a nonsynthetic materialwith a geosynthetic one for optimum performance and/orleast cost As seen in the following, the number of

possibilities is huge — the only limits being one's ingenuityand imagination.In considering the following

geocomposites, keep in mind that there are five basicfunctions that can be provided: separation, reinforcement,

filtration, drainage, and containment.


SOIL CHARACTERISTIC



FUNCTION OF GEOSYNTHETICS



The juxtaposition of the various types of geosynthetics just describedwith the primary function that the material is called upon to serve

allows for the creation of an organizational matrix for geosynthetics;

see Table 1. In essence, this matrix is the “scorecard” for understanding the entire geosynthetic field and its design related

methodology. In Table 1, the primary function that each geosyntheticcan be called upon to serve is seen. Note that these are primary

functions and in many cases (if not most) cases there are secondaryfunctions, and perhaps tertiary ones as well. For example, a

geotextile placed on soft soil will usually be designed on the basis ofits reinforcement capability, but separation and filtration mightcertainly be secondary and tertiary considerations. As another

example, a geomembrane is obviously used for its containmentcapability, but separation will always be a secondary function. Thegreatest variability from a manufacturing and materials viewpoint isthe category of geocomposites. The primary function will depend

entirely upon what is actually created, manufactured, and installed.

FUNCTION OFGEOSYNTHETICS

Table 1 - Identification of the Usual Primary



ab e de t cat o o t e Usua a yFunction for Each Type of Geosynthetic

Type of

Geosynthetic(GS)

Separation Reinforcement Filtration Drainage Containment

Geotextile (GT) X X X X

Geogrid (GG) X

Geonet (GN) X

Geomembrane(GM)

X

Geosynthetic

Clay Liner(GCL)

X

Geopipe (GP) X

Geofoam (GF) X

Geocells (GL) X X FUNCTION OFGEOSYNTHETICS

SEPARATOR



SEPARATOR

Separation is the placement of a flexible geosyntheticmaterial, like a porous geotextile, between dissimilarmaterials so that the integrity and functioning of both

materials can remain intact or even be improved. Paved

roads, unpaved roads, and railroad bases are commonapplications. Also, the use of thick nonwoven geotextilesfor cushioning and protection of geomembranes is in thiscategory. In addition, for most applications of geofoam,

separation is the major function.


REINFORCEMENT



REINFORCEMENT

Reinforcement is the synergistic improvement of a total

system‟s strength created by the introduction of ageotextile, geogrid or geocell (all of which are good in

tension) into a soil (that is good in compression, but poorin tension) or other disjointed and separated material.

Applications of this function are in mechanically stabilizedand retained earth walls and steep soil slopes; they canbe combined with masonry facings to create vertical

retaining walls. Also involved is the application of basalreinforcement over soft soils and over deep foundations

for embankments and heavy surface loadings. Stiffpolymer geogrids and geocells do not have to be held intension to provide soil reinforcement, unlike geotextiles.

FUNCTION OF

GEOSYNTHETICS



Stiff 2D geogrid and 3D geocells interlock with theaggregate particles and the reinforcement mechanism is

one of confinement of the aggregate. The resultingmechanically stabilized aggregate layer exhibitsimproved loadbearing performance. Stiff polymer

geogrids, with rectangular or triangular apertures, in

addition to three-dimensional geocells made from newpolymeric alloys are also increasingly specified inunpaved and paved roadways, load platforms andrailway ballast, where the improved loadbearing

characteristics significantly reduce the requirements forhigh quality, imported aggregate fills, thus reducing the

carbon footprint of the construction.

FUNCTION OF

GEOSYNTHETICS



FILTRATION

Filtration is the equilibrium soil-to-geotextile interaction thatallows for adequate liquid flow without soil loss, across theplane of the geotextile over a service lifetime compatible

with the application under consideration. Filtrationapplications are highway underdrain systems, retaining walldrainage, landfill leachate collection systems, as silt

fences and curtains, and as flexible forms for bags, tubesand containers.




DRAINAGE

Drainage is the equilibrium soil-to-geosynthetic system thatallows for adequate liquid flow without soil loss, within theplane of the geosynthetic over a service lifetime compatiblewith the application under consideration. Geopipe highlights

this function, and also geonets, geocomposites and (to a

lesser extent) geotextiles. Drainage applications for thesedifferent geosynthetics are retaining walls, sport fields,

dams, canals, reservoirs, and capillary breaks. Also to benoted is that sheet, edge and wick drains are

geocomposites used for various soil and rock drainagesituations.


CONTAINMENT



CONTAINMENTContainment involves geomembranes, geosynthetic clay liners,

or some geocomposites which function as liquid or gas

barriers. Landfill liners and covers make critical use of thesegeosynthetics. All hydraulic applications (tunnels, dams,canals, reservoir liners, and floating covers) use these

geosynthetics as well.

"Base for Plantation on dome" Use of geotextile was made inlittle unused application in India Pavilion at Shanghai Expo2010. Plantation was to made on a very large dome (more

than 34 m diameter). Non woven geotextile was used in twolayers. one layer was provided as a base layer and over the

same another layer was provided which was punctured at theplaces where plants were to be planted throgh stappling

process. The gap between two layers was used for irrigatingthe plants and supplying nutrients(Dr. K M Soni).




CONCLUSION

They are many ways of improving the soil characteristic .Nowadays , there are so many kind of technology in

improving the soil characteristic.

Soil is important to human kind , in all aspect of farming ,constructing, it has many types of characteristic and some

can be used freshly but some had to undergo some processso it suitable and ready to be used

CONCLUSION

REFFERRENCES



C 3008 Geotechnic 1 for Polytechnic

C 3010 Highway Engineering 1 for Polytechnic

http://en.wikipedia.org/wiki/Soil

http://en.wikipedia.org/wiki/Consolidation_(soil)

http://en.wikipedia.org/wiki/Compaction_(geology) http://en.wikipedia.org/wiki/Geosynthetic

http://en.wikipedia.org/wiki/Geotextile

http://en.wikipedia.org/wiki/Geomembranes

http://en.wikipedia.org/wiki/Geogrids

http://en.wikipedia.org/wiki/Geocomposite



http://en.wikipedia.org/wiki/Compaction_(geology)

http://en.wikipedia.org/wiki/Geosynthetic









http://en.wikipedia.org/wiki/Geosynthetic

http://en.wikipedia.org/wiki/Compaction_(geology)




geotechnic 4

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