field comp action

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RET 565BUILDING TECHNOLOGIES ANDINFRASTRUCTURES

FIELD COMPACTIONFIELD COMPACTION

Prepared By:Prepared By:Muhammad Arkam Bin Che Munaaim

SRM0069/08, 771224-07-5147www.arkamonline.com



COMPACTION-DEFINITION

Soil: The part of the earth's surface consisting of humus and

disintegrated rock, Material in the top layer of the surface of the earth in which plants can grow (especially with reference to its quality or use)

Compaction: An increase in the density of something.




Thus, SOIL COMPACTION is the process to increase the soil(ground) density in order to make use the ground surface fordevelopment, ie, building, road, etc.

The volume of void space is reduced by applying high loads over asmall area to force the air out of an unsaturated soil mass.




In other words, soil compaction is defined as the method of mechanically increasing the density of soil. In construction, this is

a significant part of the building process. If performed

improperly, settlement of the soil could occur and result inunnecessary maintenance costs or structure failure. Almost all

types of building sites and construction projects utilize mechanicalcompaction techniques.



COMPACTION-WHY COMPACT?There are five principle reasons to compact soil:

- Increases load-bearing capacity- Prevents soil settlement and frost damage- Provides stability- Reduces water seepage, swelling and contraction- Reduces settling of soil

There are four types of compaction effort on soil orasphalt:

-Vibration (Vibratory Force Compaction)-Impact (Vibratory Force Compaction)-Kneading (Static Compaction)-Pressure (Static Compaction)

COMPACTION-TYPES OF COMPACTION



COMPACTION- RISK



COMPACTION-SIGNIFICANT

To construct ROAD, highway, expressway, runway, railway,plantations, etc.



COMPACTION-SIGNIFICANT

Building constructions, drainage, embankment, externalservices, etc.



COMPACTION-SOIL TYPES

Sand, silt, and clay are the basic types of soil. Most soils are made up of acombination of the three. The texture of the soil, how it looks and feels, dependsupon the amount of each one in that particular soil. The type of soil varies fromplace to place on our planet and can even vary from one place to another in our

own backyard.



COMPACTION-SOIL TYPESEvery soil type behaves differently with respect to maximum

density and optimum moisture.Soil types are commonly classified by grain size, determined bypassing the soil through a series of sieves to screen or separatethe different grain sizes.

Soils found in nature are almost always a combination of soiltypes. A well-graded soil consists of a wide range of particlesizes with the smaller particles filling voids between largerparticles.

The are three basic soil groups:

CohesiveGranularOrganic



Cohesive soils Cohesive soils have the smallest particles. Clay has a particlesize range of .00004" to .002". Silt ranges from .0002" to.003". Clay is used in embankment fills and retaining pond beds.

Characteristics Cohesive soils are dense and tightly bound together by molecularattraction. They are plastic when wet and can be molded, butbecome very hard when dry. Proper water content, evenlydistributed, is critical for proper compaction. Cohesive soilsusually require a force such as impact or pressure. Silt has anoticeably lower cohesion than clay. However, silt is still heavilyreliant on water content.




Granular soils Granular soils range in particle size from .003" to .08" (sand)and .08" to 1.0" (fine to medium gravel). Granular soils are

known for their water-draining properties.

Characteristics Sand and gravel obtain maximum density in either a fully dry orsaturated state. Testing curves are relatively flat so density can

be obtained regardless of water content.





THE BEST PROPERTY FOR SOIL COMPACTION



METHOD-ROAD ONLY

BASIC PRINCIPLES OF FIELDCOMPACTION

PreliminariesSite Clearing & Demolition WorksStripping Of TopsoilSoil SamplingTrial EmbankmentExcavation Of Cut/Fill AreaFilling/Backfilling MaterialsReplacement Of Unsuitable MaterialsBackfilling To Unsuitable AreaEmbankment FillingRock BlastingRock Filled EmbankmentSub Grade

1) Survey: Existing ground level, settingout of centre lines and road reserved, cutand fill area, invert level and direction of water path.

2) Submission of any approvals required.Temporary road diversion if required.Submit localized environmental mitigationmeasures.

3) Routes of transportation, temporaryaccess, modes of transport, frequency andmode of filling identified.

4) Provide adequate plant and equipmentto carry out all activities.

5) Where crossing of watercourses, install temporary

steel pipe to divert water flow.6) Use machinery fitted withsilencer to reduce noise level if necessary.



METHOD-ROAD ONLY



1) Slopes, levels, and other control pegsare available at cut areas to obtain therequired design profile.

2) Confirm acceptance of material forembankment filling and/or backfillingmaterials.



METHOD-ROAD ONLY



1) Carry out soil investigation by usingMackintosh Probe to the required depth/penetration per blow.

2) Carry out setting out and joint survey

to demarcate limits and depth of unsuitable material.

3) Carry out trial pits to determine soilclassification using Alterberg 's limit orby cone penetrometer test to confirmthe recommended depth below theoriginal ground level and method of backfill used.

5) In presence of access porewater pressure , dewateringcontinuously and provide proper

drainage to prevent ingress of surface water runoff.

6) Excavate the unsuitablematerial to the extent of required depth and profiles.



METHOD-ROAD ONLY



1) Upon completion of joint measurementfor the excavation area, carry outbackfilling with granular material (sand).

2) Sewn geotextile will be laid flat on the

intended work area (if required).3) If found that ground water level

develop above the 500mm sandthickness. Further sand fill to attain300mm clearance above standing water.

4) Where ground water level is high , itwould be expected that seepage wouldeffect the first layer of earth filling. Placea slightly thicker first layer of sand fill.

5) When backfilling at the edge

of ground having slope, cut theslope edge into benches toapproximately the same as thefill level to obtain uniformcompaction over the fill area.



METHOD-ROAD ONLY


PreliminariesSite Clearing & Demolition WorksStripping Of TopsoilSoil SamplingTrial EmbankmentExcavation Of Cut/Fill AreaFilling/Backfilling MaterialsReplacement Of Unsuitable MaterialsBackfilling To Unsuitable AreaEmbankment Filling (1)Rock BlastingRock Filled EmbankmentSub Grade

1) Surface preparation to receive layerof fill. Area to be filled cleared fromexisting structures and services.

2) Control deposition of earth fill,

spread, levelled and compacted in layersless than 300mm loose depth usingsuitable plants and equipments.

3) Form embankment with suitable crossfall to avoid water ponding. While if thesurface is too dry, provide water tankerto control the moisture.

4) Loose fill levels are controlled byflagged top levels of fill to ensure

compacted fill thickness is achieved

5) Secure a team for FieldDensity Test to determine thedegree of compaction at any time.Field Density Test shall be done

using Sand Replacement Method (inaccordance with BS1377: Part 2) orby Core Cutter Method . If thedensity is below the requirements,further compaction will be carried

out.



METHOD-ROAD ONLY



1) Carry out joint survey with consultantto determine the extent of rock formation.

2) Request permission from relevant

authorities including the police tomonitor the blasting works.

3) Carry out the blasting work to therequired formation level.

4) Carry out joint survey to calculate thequantities of blasted rock.



METHOD-ROAD ONLY



1) Rock shall be defined as a material that

cannot be ripped by a drawnripper havingweight of 20 tonnes with a nett horse powernot less than 200 brake.

2) Rock fill embankment shall not more than400mm so that it can be deposited in

horizontal layers, each not exceeding 500mmin compacted depth and extending over thefull width of the embankment.

3) Spread, level and compact using crawlertractor weighing not less than 15 tonnes.

4) Fill void using fine graded material andthrough blind uniformly before proceed to thenext layer.

5) Place uniformly graded material( 6mm - 150mm ) at least 300mmthick between the top 300mm of sub

grade and the rock fill.6) Fill any void with blinded andregulate the rock surface toformation levels



METHOD-ROAD ONLY



1) Lay, spread and compact uniformlythe top 300mm and carry out FDT 95%maximum dry density (for cohesive soil)or 100% maximum dry density (forcohesiveness soil) relative to ProctorTest (4.5 kg rammer) as per BS 1377.

2) If the compaction achieve below therequirement, scarify the surface, leave itto dry recompact and retest. If it is stillunpractical, remove the top sub grade

layer and replace with suitable materialand compact to the required density.

3) Tolerance for sub grade finish layershall be within + 10mm to 30mm of therequired gradient and level.

Sub base

Sub grade

Binder Course

Wearing Course

Sand Blanding

Prime Coat

Tack Coat



COMPACTION-MACHINERIES




Rammers deliver a high impact force ( high amplitude) making them an excellentchoice for cohesive and semi-cohesive soils. Frequency range is 500 to 750 blowsper minute. Rammers get compaction force from a small gasoline or diesel enginepowering a large piston set with two sets of springs. The rammer is inclined at aforward angle to allow forward travel as the machine jumps. Rammers cover threetypes of compaction: impact, vibration and kneading.




Vibratory plates are low amplitude and high frequency, designed to compact granular

soils and asphalt. Gasoline or diesel engines drive one or two eccentric weights at ahigh speed to develop compaction force. The resulting vibrations cause forwardmotion. The engine and handle are vibration-isolated from the vibrating plate. Theheavier the plate, the more compaction force it generates. Frequency range is usually2500 vpm to 6000 vpm. Plates used for asphalt have a water tank and sprinklersystem to prevent asphalt from sticking to the bottom of the base plate. Vibration isthe one principal compaction effect.




Reversible Vibratory PlatesIn addition to some of the standard vibratory plate features, reversible plates have twoeccentric weights that allow smooth transition for forward or reverse travel, plusincreased compaction force as the result of dual weights. Due to their weight andforce, reversible plates are ideal for semi-cohesive soils. A reversible is possible thebest compaction buy dollar for dollar. Unlike standard plates, the reversible forward

travel may be stopped and the machine will maintain its force for "spot" compaction.



COMPACTION & CLIMATE Although compaction may not change the water content of a soil, themaximum density obtainable does depend on the amount of waterpresent in the soil mass.

Because the individual particles in a course grained soil are chemicallyinert, there is a little interaction between the solid and liquid fraction of a soil mass.

The effects of water in the deposit is largely through the formation of

capillary tensions, with result in the particles being tightly bound in amatrix that resist rearrangement.

As a degree of saturation increases, the capillary forces are destroyedand compaction energy becomes more effective in densifying the soil.

For most cases, the optimum water content yielding the greatestdensity of the solid fraction (dry density) can be identified.

At water content at both below and above the optimum, the samecompaction effort in result lower soil density.



COMPACTION & CLIMATE

Source: Encyclopedia of Soil Science, R.Lal, William E Wolfe, Ohio State University, Columbus, Ohio, USA, 2006




Example of Test Results:




COMPACTION & CLIMATEExample of Test Results:

OPTIMUM MOISTURE CONTENT




COMPACTION & CLIMATESince the Moisture Content, W is much depending on theweight of water, Wd , it is obvious that the climate conditionwill effect the quality of compaction in any area of compaction.It is important to know the Optimum Moisture Content for thesoil so that the energy used for saturation process is also atoptimum and resulting in the quality of compaction works.

There will be some amount of moisture needed in compactionprocess, the compaction is not recommended to be doneeither in a too dry or too wet condition to achieve the goodand quality compacting results.




The response of soil to moisture is very important, as the soil mustcarry the load year-round. Rain, for example, may transform soil into aplastic state or even into a liquid. In this state, soil has very little or noload-bearing ability.


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