This document discusses different types of soils found in India and their characteristics that affect soil behavior. It also discusses different types of foundations used depending on the soil type, including pile foundations and raft foundations. The main types of soils described are alluvial, black, red, laterite, mountain, and desert soils. Key soil characteristics discussed are cohesion, internal friction, and permeability. The document also examines different pile foundation types based on function (bearing, friction, screw, etc.) and material (timber, concrete, steel). Raft foundation types including flat plate, thickened, beam-slab, and cellular foundations are also summarized.

1. SOIL TYPES AND ITS
BEHAVIOUR
BUILDING TECHNOLOGY AND MATERIALS III
TERM I

2. 2
SOIL
Soil is a mixture of minerals, organic matter, gases, liquids and countless
organisms that together support life on Earth.
• Climate
• Relief (Elevation, Orientation, Slope Of Terrain)
• Organisms
• Original Minerals
All influence the type of Soil

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Six Different Types of Soils Found in India
• Alluvial Soils: formed by the deposition of sediments by rivers
• Black Soils: are made up of volcanic rocks and lava-flow
• Red Soils: derived from weathering of ancient metamorphic rocks of Deccan Plateau
• Laterite Soils: formed due to intense leaching
• Mountain Soils: formed as a result of the accumulation of organic matter
• Dessert Soils: generally sandy and deficient in organic matter

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Characteristics of soil
Characteristics of soil that affects its behavior and which are considered while
designing foundations are
• Cohesion of particles
• Internal friction
• Permeability
These characteristics are further classified depending on the quantity of
following components:
Rock
Gravel and sand
Chalk
Clay
Peat

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Rock
• Rocks such as limestone, granite, sandstone, shale and hard solid chalk have a high
bearing capacity.
• Rock can be impervious, so topsoil is likely to require drainage as it is not possible to
build soak pits to dispose of rainwater or surface water.
Sand
• Under load sand is slightly compressed due to discharge of water.
• Because of its high permeability rate, compression is rapid.
• Sand has negligible cohesion between particles thus doesn't have plasticity.
• Thus weight of building on sand causes rapid compression with little disturbance to
the surrounding soil.
Gravel and sand
• Dry compact gravel, or gravel and sand sub soils are most suitable for foundations
when well drained and well confined.
• They have good bearing value and are adequate for strip foundations.
• Depth of 700mm is acceptable, as long as the ground has adequate bearing capacity.
• If the water table is high, the bearing capacity is halved
• In such cases a shallow, reinforced, wide strip foundation may be suitable.

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Chalk
• It is a soft, white, porous sedimentary
carbonate rock
• Strip foundations are commonly used in
chalk.
• The depth of the foundation must be below
700mm
• If the chalk is soft it will need to be
excavated until firm chalk is reached.
• Chalk soils can be prone to erosion
Peat
• Peat and loose waterlogged sand are poor
subsoils.
• If the peat can be stripped back to find
suitable load-bearing ground of at least
1.5m depth, strip foundations may be
suitable.
• A reinforced raft foundation are preferred.

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Clay
• 900-1,200mm layer of clay is subjected to movement due to expansion and
shrinkage
• Clay is very compressible but due to high cohesiveness the compression
takes place slowly and it also affects the surrounding surface.
• Excavation is done till a depth where the moisture content of the clay
remains stable.
• Strip foundation is sometimes acceptable but over digging shouldn’t be done
as it leads to more stress on softer clay blow
• Strip foundations with steel reinforcement are used at times
• Minimum depth of 1m is required for foundation

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The choice of the appropriate type of
foundation is also governed by following
factors such as:
• The nature of the structure
• The loads exerted by the structure
• The subsoil characteristics
• The allotted cost of foundations
• The first factor considered is loads
from building on the foundation.
• This load is a combination of dead
load and imposed loads on
the buildings.
• Other loads such as wind loads,
earthquake loads, snow loads etc. are
also considered based on location.

9. FOUNDATION ON WEAK STRATA:
RAFT AND PILE FOUNDATION
BUILDING TECHNOLOGY AND MATERIALS III
TERM I

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PILE FOUNDATION:
FUNCTION:
As with other types of foundations, the purpose of a pile foundations is:
• To transmit a foundation load to a solid ground
• To resist vertical, lateral and uplift load
PILE FOUNDATION ARE ADOPTED FOR
• Soils having Low Bearing capacity
• Non availability of proper bearing stratum at shallow depths
• Heavy load from the super structure for which shallow foundation may not be
economical or feasible

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PILE FOUNDATION BASED ON FUNCTION
1. Bearing Piles
2. Friction Piles
3. Screw Plies
4. Compaction Piles
5. Sheet Piles
PILE FOUNDATION BASED ON MATERIAL
1. Cement Piles
2. Timber Piles
3. Steel Plies
4. Composite Pile

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PILE FOUNDATION BASED ON FUNCTION

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1. BEARING PILES
• Bearing pile are driven until it reaches to hard stratum
• Pile acts as pillars supporting the super structure and
transmitting the load down to hard stratum from the
ground
• Bearing Pile do not bear any load, they act as a medium
to transmit the load
2. FRICTION PILES OR
FLOATING PILES FOUNDATION
• Friction pile are used when hard
stratum is very deep or not available
or soil is weak to carry the load of
super structure
• The load is transferred by the friction
developed between piles and
surrounding ground

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3. SCREW PILES
• Construction of helical plates welded to hollow
steel pile
• Rapid installation can be done
• Little installation noise or vibration
• Sustain load immediately after installed
• They do not work on rocky terrain
• Shaft can be as small as 1.5x1.5 inches solid
bar.
4. COMPACTION PILES
When granular piles are driven in granular soil with
the aim of increasing the bearing capacity of the
soil the pile is termed as compaction pile

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5. SHEET PILES
• Sheet pile differs from bearing or friction piles
• Used rarely to furnish vertical support and are
used to fulfill the function of a retaining wall
• The ground anchor is provided to hold sheet in
place

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PILE FOUNDATION BASED ON MATERIALS

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1. TIMBER PILE / WOODEN PILE
ADVANTAGES:
• The piles are easy to handle
• Relatively inexpensive where timber is plentiful.
• Timber is most suitable for long cohesion piling
and piling beneath embankments.
• For timber piles of length less than 14 meters,
the diameter should be greater than 150 mm.
• If the length is greater than 18 meters, the
diameter of 125 mm is acceptable.
• It is essential that the timber is driven in the
right direction and should not be driven into
firm ground

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1. TIMBER PILE / WOODEN PILE
DISADVANTAGES:
• Not suitable in all conditions.
• The piles will rot above the ground water
level if they are not treated properly.
• Have a limited bearing capacity.
• The timber should be in a good condition
and should not have been attacked by
insects.

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PRECAST CONCRETE PILES
ADVANTAGES
• The piles can be cast before excavation.
• Can be inspected before casting can easily be cut or
extended to the desired length.
• Relatively inexpensive.
• Pile lengths are readily adjustable.
DISADVANTAGES
• Concrete cannot be inspected after completion.
• Light steel section or Precast concrete shells may be
damaged or distorted by hard driving.
• Cannot be driven where headroom is limited
• Time consuming. Cannot be used immediately after the
installation.

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CAST IN-SITU
ADVANTAGES
• Length can be readily varied to suit varying ground conditions.
• Soil removed in boring can be inspected
• Can be installed in very large diameters and lengths
• End enlargement up to two or three diameters are possible in clays.
• Material of piles is not dependent on handling or driving conditions.
• Can be installed with out appreciable noise or vibrations.
• Can be installed in conditions of very low headroom.

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CAST IN-SITU
DISADVANTAGES
• Supervision has to be done so that the concrete is placed under ideal
conditions. But in situ piles cannot be subsequently inspected.
• Water under artesian pressure may pipe up pile shaft washing out cement.
• Cannot be readily extended above ground level especially in river and marine
structures.
• Boring methods may loosen sandy or gravely soils requiring base grouting to
achieve economical base resistance.

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3. STEEL PILES
• Suitable for handling and driving in long lengths.
• Their relatively small cross-sectional area combined with their high strength
makes penetration easier in firm soil.
• They can be easily cut off or joined by welding.
• Anti corrosion coating is applied on all surfaces to protect the metal
The types of steel piles commonly used are
a) H-piles b) Pipe piles c) Screw piles

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4. COMPOSITE PILE FOUNDATION
• Combination of different materials in the same of pile.

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RAFT FOUNDATION:
• The raft foundation is a continuous footing
that covers the entire area beneath a
structure and supports all the walls and
columns.
• The principal of any raft foundation is to
spread the load of the entire area of the site.
• It may be stiffened by ribs or beams
incorporated into the foundation.
• They are made up of concrete and heavily
reinforced with steel, so entire foundation
will act as a unit.
• The term mat is also used for the foundation
• A raft is an alternative to piles as it can be
less expensive.

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WHERE RAFT FOUNDATIONS ARE USED ?
• The raft foundations are used where the column load are heavy and thus
requiring large bases.
• Where the bearing capacity of soil is low, resulting in the need of large
base.
• If the subsoil is soft compressible such as soft clay or peat.
• If the bottom of the structure is located below the ground table level.
• It is also used where the area covered by spread footings is more than
half the area covered by the structure.

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FLAT PLATE RAFT FOUNDATION
• These are constructed of uniform thickness over the whole raft area..

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FLAT PLATE THICKENED UNDER FOUNDATION
• These are constructed of uniform thickness over the whole raft area..

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BEAM AND SLAB RAFT FOUNDATION
• Beam and slab rafts are alternatives to the
solid slab raft and are used where poor
soils are encountered.
• The beams are used to distribute the
column load over the area of the raft, that
results in the reduction of the slab
thickness.
• The beams can be up stand or down stand
depending upon the bearing capacity of
soil near the surface.

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CELLULAR RAFT FOUNDATION
• These type of foundations are
used on soft compressible
subsoil such as soft clay or peat.
• These rafts are used on sites
subject to severe mining activity
or in areas of poor ground where
large bending
moments are to be resisted.