A DETAILED PPT OF DEWATERING BY ELECTRO OSMOSIS METHOD ALONG WITH APPLICATIONS OF ELECTRO-OSMOSIS IN CIVIL ENGINEERING.

1. BUILT
IT
UP
PRESENTED BY:
Ms. Tejaswini Narayane
Mst. Vaibhav Phatangare
Mst. Dipesh Dhadave
Mst. Dishank Raut
PROJECT GUIDE:
Prof. Dhanashri Joshi
BY- TEJASWINI NARAYANE
New Horizon Institute Of Technology & Management (Thane)
BRANCH: B.E. CIVIL ENGINEERING. SEMESTER: 4th

2. TOPIC
DEWATERING IN DIFFERENT
SOIL CONDITIONS:
ELECTRO – OSMOSIS METHOD
BY- TEJASWINI NARAYANE

3. • WHAT IS DEWATERING?
• IMPORTANCE OF DEWATERING.
• BASIC PROCESS OF DEWATERING.
• METHODS OF DEWATERING.
• ELECTRO – OSMOSIS METHOD OF DEWATERING.
• RESULTS.
• CONCLUSION.
• APPLICATIONS OF ELECTRO-OSMOSIS IN CIVIL
ENGINEERING.
• WATER MANAGEMENT & DISPOSAL OF DEWATERED
WATER.
• EXAMPLES.
BY- TEJASWINI NARAYANE
CONTENTS

4. WHAT IS DEWATERING?
• ‘Dewatering’ – Artificial means of removing
groundwater or surface water.
• Dewatering Process – done by pumping or evaporation
methods.
• On construction sites it may be known as
‘CONSTRUCTION DEWATERING’.
• Dewatering means “the separation of water from the
soil,” or perhaps “taking the water out of the
particular construction problem completely.”
BY- TEJASWINI NARAYANE

5. • Completely Dry Surface.
• Easy Workability of construction Workers.
• During Excavation – Safety of Workers & to
Achieve Stability of Foundation.
• During Monsoons – for Smooth & Fast
Working Progress.
• Other Essential Reasons – Washing of plant,
etc.
BY- TEJASWINI NARAYANE
IMPORTANCE OF
DEWATERING

6. BASIC PROCESS OF DEWATERING
COLLECTION
OF WATER
TO BE
DEWATERED.
PUMPING:
ANY
DEWATER-
ING METHOD
FILTERATION
OF
IMPURITIES,
SILTS &
OTHER
SCRAPS.
DISCHARGE
&
DISPOLSAL
AT PROPER
LOCATION &
CARE.
BY- TEJASWINI NARAYANE

7. PERMEABILITY OF SOIL
SOIL PERMEABILITY
COEFFICENT (K)
CM/SEC
RELATIVE
PERMEABILITY
COARSE GRAVEL EXCEEDS 10^-1 HIGH
CLEAN SAND 10^-1 TO 10^-3 MEDIUM
DIRTY SAND 10^-3 TO 10^-5 LOW
SILT 10^-5 TO 10^-7 VERY LOW
CLAY LESS THAN 10^-7 IMPERVIOUS
BY- TEJASWINI NARAYANE

8. METHODS OF
DEWATERING
Factors such as Type of Soil & Nature of Construction
Site will all influence, which Dewatering Method will be
Best Suited for the Project.
• OPEN SUMPS AND DITCHES
• WELL POINT SYSTEMS
• DEEP WELL DRAINAGE
• VACUUM DEWATERING SYSTEMS
• ELECTRO OSMOSIS
BY- TEJASWINI NARAYANE

9. METHOD SUITABILITY
SUMP PUMPING FOR SHALLOW EXCAVATION IN
COARSE GRAINED SOIL.
WELL POINT SYSTEMS SUITABLE FOR LOWERING THE
WATER TABLE BY 5-6 METERS
IN SOILS.
DEEP WELL POINT SYSTEM FOR COARSE GRAINED SOILS
& DEPTH OF EXCAVATIONS OF
MORE THAN 16 METERS.
VACUUM PUMP DRAINING SILTY SANDS WITH
FINE SANDS
ELECTRO – OSMOSIS
DEWATERING
SUITABLE FOR FINED
GRAINED COHESIVE SOILS
SUCH AS CLAYS
BY- TEJASWINI NARAYANE
SUITABILITY OF
DEWATERING METHODS

10. • Electro-osmosis Is Defined As "The
Movement Of Water (And Whatever Is
Contained In The Water) Through A
Porous Media By Applying A Direct
Current (Dc) Field.
• This Technique of Dewatering Done
Through The Use Of Cathodes & Anodes
With Passage Of Electrical Current.
• This Is The Only Effective Method Of
Dewatering In Deep Clay Soils.
• This Method Was Developed By L.
Casagrande (1952).
BY- TEJASWINI NARAYANE
ELECTRO – OSMOSIS METHOD OF
DEWATERING

11. • The Cathode is made in the form of Well
Point / metal tube for pumping out the
seeping water.
• A Steel Rod, a Pipe or a Steel Piling of
excavation can serve as a Cathode.
• The Arrangement of Electrodes is done in
such a way that the natural direction of flow
of water is reversed away from the
excavation thereby, increasing the strength
of the soil & stability of the slope.
BY- TEJASWINI NARAYANE

12. • The potentials generally used in the
process are from 40 – 180 volts, with
electrodes spacing 4 – 5 meters.
• This dewatering system is very
expensive in nature as it calls for
impeccable experienced team to do
the job.
• The flow of ions in Electro –
Osmosis Processes of Dewatering is
known as Ionic Flow or Phreatic
Flow.
BY- TEJASWINI NARAYANE

13. These Are The Following Results Of Electro-osmosis Method Of Dewatering
When Applied Properly :
• Electro-osmosis Provides Uniform Pore Water Movement In Most Types
Of Soil, Since The Boundary Layer Movement Towards Cathode Provides
The Motive Force For The Bulk Pore Water.
• Electro-osmotic Flow Rate Is Not Sensitive To Pore Size.
• Electro-osmotic Flow Rate Is Primarily A Function Of Applied Voltage.
• The Entire Soil Mass Between The Electrodes Is Basically Treated
Equally.
• Hence, Electro-osmosis Is So Effective In Clayey & Heterogeneous Soils.
RESULTS
BY- TEJASWINI NARAYANE

14. CONCLUSION
The method of electro-osmotic dewatering has the following
conclusions:
• The sludge is homogeneous and fully saturated.
• The main after effect of this method is the soil consolidation.
• The water in the sludge moves electro osmotically in the one-
dimensional , direction between electrodes.
• The electroosmotic permeability(k), is constant with time; No
electrochemical reactions occur during electro-osmotic
dewatering; Darcy's law and Ohm's law are applicable during
electro-osmotic dewatering.
BY- TEJASWINI NARAYANE

15. • Stabilization Of Slopes
• Excavations
• Embankments
• Controlling Groundwater Flow
• Increasing Pile Capacity
• Improving The Strength Of Clays
• Dewatering Tailings And Sludge
• Improving Soil After A Landslide
APPLICATION OF ELECTRO-
OSMOSIS METHOD IN CIVIL
ENGINEERING
BY- TEJASWINI NARAYANE

16. WATER MANAGEMENT &
DISPOSAL OF DEWATERED
WATER
• Water should never be pumped directly into slopes.
• Discontinue dewatering if the area shows signs of instability
or erosion.
• Channels used for dewatering need to be steady and
protected by grass and vegetation.
• Never dewater during heavy rains. The water and infiltration
rate will be slower during the dewatering process or it will not
function entirely.
• Never discharge water that contains oil, grease, or chemical
products.
• Make sure to acquire any additional permits from state, local,
or federal agencies.
BY- TEJASWINI NARAYANE

17. DEWATERING BAGS FOR CLAYEY / SLITY SOIL ( FOR ELECTRO-OSMOSIS METHOD)
ELECTRODES PLACED IN FIELD FOR
CONSOLIDATION OF SOIL
OPEN SUMP & DITCHES METHOD OF
DEWATERING
BY- TEJASWINI NARAYANE

18. COFFERDAM
WELL-POINT METHOD OF DEWATERING
VACCUM PUMP METHOD OF DEWATERING
DEEP-WELL METHOD OF DEWATERING
BY- TEJASWINI NARAYANE