to assume seepage in earthen dam

2. UMER FAROOQ ALAM
REG NO SU-19-01-134-005
PROGRAM MS CIVIL TECHNOLOGY
CLASS SOIL TECHNOLOGY
TOPIC BASED ON DETERMINE SEEPAGE
IN EARTHEN DAM. DRYING FLOW NET.

3. SEEPAGE IN EARTHEN
DAM
 What is seepage?
 Reason of seepage?
 Earthen Dam and how it made?
 Causes of seepage in earthen dam?
 Seepage analysis?
 Drying flow net?

4. What is seepage?
 The process by which liquid leaks
through a porous substances.
 The slow escape of a liquid or gas
through porous material or small
holes.

5. Gathright Dam on the Jackson
River, near Covington

6. Reason of seepage?
 Due to internal erosion means waves
pressure
 Saluting of soluble rock
 Excessive internal friction or saturation
 Piping through foundation
 Piping to dam body
 Sloughing of downstream toe.

7. Piping through foundation

8. Piping through dam body

9. Sloughing of downstream

10. Earthen dam short definition
 Earth dams are constructed across
rivers and valley to retain water for the
purpose of protection from floods.
Storage of water. diversion of water to
canal in high lands.
 Constructing one type soil layer and
also from more then one type of soil
layers.(soil.clay,sand,rock)

12. Causes of seepage in earthen
dam?
 Seepage is important factor that has
to be carefully study during the design
of an earth dam.
 Seepage analysis can be used to
estimate following line.
 Flow lines
 Equipotentail lines
 Pheratic ines

14. Seepage analysis?
 To estimate the quantity of
seepage(rate of leakage)through dam
using flow net.
 Assumption
 Soil is homogenous and isotropic.
 Size of pore spaces do not change
 darcy`s laws is valid (Flow is laminar)
 Soil fully saturated 100%

15. continued
 During flow volume of soil and water
remain constant.

16. Flow net diagram of seepage

17. Formula used in flow net

18. Example on flow net