3. DEFINITION
Deep Foundations are those
In which the depth of the foundation is very large in comparison to its width.
Which are not constructed by ordinary methods of open pit excavations.
4. Forms of Construction
Most common forms of construction pertaining
to deep foundations are:
Pile Foundation (more commonly used in building construction)
Cofferdams
Caisson or Well Foundation
5. Pile Foundations
The term ‘Pile Foundation’ denotes a construction for
the foundation of a wall or pier which is supported on
piles.
Where Used :
stratum of required bearing capacity is at greater depth
Advantages:
Provides a common solution to all difficult foundation site
problems
Can be used for any type of structure and in any type of soil
7. Types of Piles Based on
Function
Classification based on Function or Use
Bearing Piles or End Bearing Piles
Friction Piles or Skin Friction Piles
Sheet Piles
Tension Piles or Uplift Piles
Anchor Piles
Batter Piles
Fender Piles
Compaction Piles
8. Types of Piles Based on Function
Bearing Piles
Driven into the ground until a hard
stratum is reached.
Acts as pillars supporting the super-
structure and transmitting the load to
the ground.
Friction Piles (Floating Piles)
Piles are driven at a site where soil is
weak or soft to a considerable depth
and it is not economical or rather
possible to rest the bottom end of the
pile on the hard stratum.
10. Types of Piles Based on
Function
Sheet Piles
Sheet piles are used for the following purposes:
To construct retaining walls in docks, and other marine works.
To protect erosion of river banks.
To retain the sides of foundation trenches.
12. Types of Piles Based on Function
Anchor Piles
Piles are used to provide anchorage against horizontal pull from sheet piling
wall or other pulling forces.
Batter piles:
Piles are driven at an inclination to resist large horizontal and inclined forces.
Fender piles:
Piles are used to protect concrete deck or other water front structures from
the abrasion or impact caused from the ships or barges.
Compaction piles:
When piles are driven in granular soil with the aim of increasing the bearing
capacity of the soil, the piles are termed as compaction piles.
14. Types of Piles Based on
Materials
Classification based on Materials
1. Timber Piles
2. Concrete Piles
3. Composite Piles
4. Steel Piles
15. Types of Piles Based on Materials
Timber Piles:
Transmission of load takes place by the frictional resistance
of ground and the pile surface.
Advantages of Timber Piles:
Economical where timber is easily available.
Can be driven rapidly & as such saves time.
Disadvantages of Timber Piles:
Liable to decay or deteriorate by salt water/insects.
Low bearing capacity.
19. Concrete Piles
Advantages of Pre-cast Piles:
Very effective
Simple quality control
Improves the entire area
Disadvantages of Pre-cast Piles:
Limited in length
Difficult to transport
Not suitable for densely built up area
21. Advantages of Cast-in-Situ Concrete Piles:
Not limited in length
Can be cast at any place
Requires less equipment
Disadvantages of Cast-in-Situ Concrete Piles:
Quality control is difficult
Load carrying is mostly done through end bearing
only
Skin frictional resistance is very low.
CONCRETE PILES
23. Composite Piles
Piles of two different
materials are driven
one over the other,
so as to enable them
to act together to
perform the function
of a single pile.
This type of
composite pile is
used with the object
of achieving
economy in the cost
of piling work.
24. Steel piles
Types of Steel Piles:
The types of steel piles commonly used are:
H-Piles
Pipe-piles
Screw piles
Disc piles
26. CONSTRUCTION PROCEDURE OF PILE FOUNDATION
At first, with the help of boring
ring machine drill the hole of
diameter 1 m upto the depth
mentioned in the drawing.
Provide casing at upper surface of
the soil Layer during the drilling.
The depth of the excavated bore
hole is measured with the help of
a chain.
After that, the length of the chain
is then measured with a tape and
compared with the required
depth of the borehole
27. • If the depth of the bore hole
confirms to the design
depth(31m) then water
mixed with geo polymer is
pumped into the bore hole
so as to prevent the caving
in of the sides of the bore
hole.
• After that, install the
reinforcement in four parts
as the depth of the bore
hole is more than 30 m.
• The bottom part of the
second reinforcement is
welded to overlap with first
reinforcement .
caging
28. After that the mouth of hopper
connected to the tremie pipe is
blocked with a plate and the
entire hopper filled with concrete
which are taken from transit
mixer.
The plate is then removed and the
concrete is allowed to flow
through it continuously.
This is done to prevent joint in the
concrete all through the pile
length.
After one batch has been poured
the tremie pipe is uplifted up and
down to allow the flow of
concrete in the pipe.
29. The bottom position of the tremie
pipe should always remain
embedded in the concrete in order
to maintain a continuous concrete
surface.
After every batch of concrete is
placed the length of the tremie pipe
is shortened by removing one part.
This is how the concreting is
completed for the cast in situ bored
piles.
The pile is always cast some length
above the desired level and cut at a
later stage by chipping to bring the
pile to the desired level of the pile
cap.
30. This is done because the
concreting in the top
portion of the pile may
get disturbed which
otherwise will reduce its
load carrying capacity.
Over the group of piles
the pile cap is then cast.
31. Causes of failure of piles
Unequal settlement of the sub-soil.
Unequal settlement of masonry.
Horizontal movement of the soil adjoining the
structure.
Shrinkage due to withdrawal of moisture from the soil
below the foundation.
Lateral pressure tending to over-turn the structure.
Action of atmosphere.
Lateral escape of the soil below the foundation.
