a presentation about earth dams with a case study. detailed presentation with everything related to earth dams (introduction,advantages,disadvantages and alot more)

2. AND

3. • Definition Of Earth Dams:
- Earth-fill dams, also called
earthen dams, rolled-earth dams
or earth dams, are constructed as
a simple embankment of well-
compacted earth.
- A homogeneous rolled-earth
dam is entirely constructed of
one type of material but may
contain a drain layer to collect
seep water.

4. Homogeneous
Earthen dam
This is type of
earthen dams with
simple earthen
embankments, built
in a single material
so it is homogenous.
Diaphragm
Earthen dam
This type of
embankment dam
has an impermeable
core called
diaphragm which is
surrounded by earth
or rock
Zoned Earthen
dam
This type of
embankment have a
central impermeable
core covered by a
transition zone that
surrounds the
previous outer zone,
central core is useful
to check seepage.

5. Such a
homogeneous
section is used for
low to medium high
dams and also for
levees
Homogeneous
Earthen dam
The diaphragm acts as
a water barrier to
avoid seepage
through the dam, it is
located in the center
of the dam section,
upside down, or
located like a blanket
Diaphragm
Earthen dam
The transition zone is
useful to prevent
piping through cracks
that may be likely to be
installed in the central
core.
Zoned Earthen
dam

6. 1. It can be constructed on any types of
foundation strut which includes soil, gravel,
earth moorum, rock, etc.
2.This type of dam is suitable for places
where there are very wide valleys.
3.Earth dam can be constructed with the use
of locally available natural materials, hence
reduces the cost of transportation.
4.The design of such a dam is flexible so that
a wide variety of materials can be used for
the construction.
5. There is a continuous process of
manufacturing with a highly mechanized
system.
1. An earth dam requires a complementary
structure to a spillway.
2.Excessive leakage and foundation erosion
is more likely.
3.Inadequate capacity of the spillway causes
dam structure failure as there is potential
for over-exploitation of the dam.
4.Burrowing animals can damage the dam’s
structure.

7. Hearting(core): It is
the central part of the
dam constructed by the
clayey soil.
Casing: The core is
surrounded by a layer
and this layer is known
as casing, constructed
by soft rock or sand
and gravel.
Rock toe: Rock toe is
constructed of small
stone or rock pieces
whose size is larger
than 20cm. Rock toe
provides stability to the
dam and prevents it
from seepage.
Pitching: Stone of size
30cm can be used for
layering (thickness
30cm -45cm). This
layer is known as
pitching in dams and it
prevents sudden
drawdown and provides
stability.
Turfing: Turfing is a
process of planting a
special type of grass
called doob or turfing
grass on the downstream
face of the dam. It
prevents water logging
due to heavy rainfall.
Drain: A series of drains is
constructed containing
different types of drains
that are longitudinal
drains, cross drains and
toe drains on the
downstream side of the
dam.
Transition filters: It is
a filter provided in
between the clayey soil
layer and sandy shell to
avoid pore pressure.

8. ROLLED
FILL
HYDRAULIC
FILL
CONSTRUCTION
PROCESS

9. 1. Hydraulic fill method
In this method of construction, first of all, excavation of soil is done then the soil is transported by the water
to construct the dam structure. Pipes are laid along the outer face of the embankment. All the soil materials
are mixed with the water then poured into the pipes.
All the necessary steps are done by the hydraulic method. No compaction is done by a roller as the soil
gets deposited by the hydraulic operation.
2. Rolled fill method
In this method of construction, a machine is used for excavation of soil, placing a layer of thickness 20cm
and compacting at optimum moisture content.
This is a very popular method for constructing the earthen dam. The soil is brought to the site from the pit
by the bulldozer and compacted by the roller.
Hydraulic fill
method
Rolled fill method

10. Structural failure
• Failure by the burrowing animal
because it causes damage.
• Failure by spreading
of waterlogging.
• Slope failure by the seepage
water.
• Landslide due to instability of the
soil particles.
• Foundation slides by the
reduction of the strength by the
continuous flow of seepage
water.
• A sudden drawdown may cause
upstream slope failure.
• Pore pressure may cause
upstream/ download slope
failure.
Hydraulic failure
• overtopping of the dam height
due to the overflow of the river
and if the capability spillway is
not sufficient.
• Due to wave erosion, the soil
gets loose or gets removed
from the upstream face of the
dam.
• Toe erosion: erosion takes
place due to the storage of
water of tail water
• Gullying: construction of gully
in the earthen dam causes
heavy downpour and it can be
prevented by providing a berm
or good drainage system.
Seepage failure
• Piping: The flow of the water
from the foundation can make
the soil loose and reduce the
strength of the foundation and
cause erosion of leaks and
lead to a large number of
catastrophic failures.
• Sloughing: Failure caused by
the sloughing is slightly similar
to the piping. The downstream
is saturated and it may erode,
produce a small slump, or slide
in the condition of the full
reservoir.

11. • We are going to take tarbela dam as an example of earth dam :
- Tarbela Dam, one of the largest earth-filled dams in the world, is a critical source of
hydroelectric power and irrigation water for Pakistan.

12. • Tarbela Dam, located on the Indus
River in the province of Pakistan,
is one of the largest earth-filled
dams in the world. It was
constructed in the late 1960s and
early 1970s with the help of
international funding, including
from the World Bank.
• The primary purpose of Tarbela
Dam was to generate hydroelectric
power for Pakistan's growing
energy needs, and it has been
successful in doing so.

13. • It stands at a height of 485 feet and stretches for 9,000 feet along the riverbank.
The dam has a total capacity of 13.69 billion cubic meters of water.
• The power station at Tarbela Dam has a total installed capacity of 4,888 megawatts,
making it the largest hydroelectric power station in Pakistan. The dam's reservoir
also serves as a major source of irrigation water, with an annual release of 75.8
billion cubic meters.

14. • Tarbela Dam is the largest
hydropower project in Pakistan,
generating approximately 3,478
megawatts of electricity.
• The dam plays a crucial role in
reducing load shedding across the
country, ensuring that industries and
households have access to
uninterrupted power supply.

15. • In conclusion, Tarbela Dam has played a crucial role in Pakistan's energy and
agriculture sectors.
• With its vast capacity to generate electricity, it has helped reduce load shedding and
provided a reliable source of power for millions of people.