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Types of Soil• Three categories of soil: cohesionless,

cohesive and organic soils.• Cohesionless soil : the soil particle

do not tend to stick together.• Cohesive soils are characterized by

very small particle size where surface

chemical e ects predominant. Theparticles do tend to stick together-theresult of water-particle interaction andattractive force between particles.

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• Three common type of cohesionlesssoils are gravel, sand and silt.

• Both gravel and sand maybe further

divided in to !ne" #as !ne sand$ andcoarse sand"#as coarse sand$

Cohesionless soilstypes

Sizes

%ravel %reater than &

mmsand '.( mm to &

mm

silt '.'') to '.(mm

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• %ravel and sand can be classi!edaccording to particle size by sieveanalysis.

• The common type of cohesive soil isclay, which has particle sizes lessthan about '.'') mm.

• *layey soils cannot be separated bysieve analysis in to size categories

because no practical sieve can bemade with openings so small+instead, particle sizes may be

determine by observing settling

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Engineering propertiessoils

• Granular soi ls , e cept for loose sand, generallypossess e cellent engineering properties:

• arge bearing capacity•

mall settlement• /ake outstanding foundation material for

supporting roads and structure.• /ake e cellent back!ll materials for retaining

wall because they are easily compacted andeasily drained, and because they e ert smalllateral pressures.

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• Cohesive soi ls #mostly clays, but alsosilty clays and clay-sand mi tures with

clay being predominant$ e hibit generallyundesirable engineering propertiescompared with those of granular soils:

• ower shear strength.• They can be plastic and compressible, and

they e pand when wetted and shrinkwhen dry.

• They develop large lateral pressure andlow permeability0s.

• 1oor material for retaining wall back!ll.

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• Silty soils are on the borderbetween clayey and sandy soils.

They are !ne-grained like clays butcohesionless like sand.

• ilty soils possess undesirable

engineering properties :• 2igh capillarity and susceptibility to

frost action, yet they have low

permeability and low densities.

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• 3ny soils containing a su4cientamount of organic matter to a ect itsengineering properties is calledorganic soils .

• 5rganic soils are typically spongy,

crumbly, and compressible. Theyposses low shear strength and maycontain harmful materials.

•

5rganic soils are essentiallyunacceptable for supportingfoundation.

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MACKINTOSH !O"E• 1roba /ackintosh atau proba 678

adalah satu kaedah yang telah diperkenalkan untuk penyiasatantanah di peringkat awal. 9anyaadalah satu kaedah yang palingmurah dan sering diguna pakai untuk

tu uan penyiasatan tapak.• 1enentuan keupayang galas

tanah#bearing capacity of soils$

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Rajah 1: Susunan umum proba JKR (a), penunjuk proba JKR(b) dan penunjuk proba mackintosh (c).

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Stan#ar# enetration test$ASTM % &'()*

• ;seful in determining certain properties ofsoils, particularly of cohesionless soils, forwhich undisturbed sample are not easily

obtained.• hammer falling ?

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• The 1T resistance value #or >-value$is number of blow reAuired to

penetrate the last =') mm.• Thus, the >-value represent the

number of blow per foot#=')mm$.

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Metho# to correct+N+value

irst /ethod #1eck et al, (C?@$

econd /ethod Terzaghi et al, (CC< and iaoand Dhitman

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TYPICAL BORE LOG FOR A PROJECT IN

MALAYSIA

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END