The document discusses the process of dewatering in civil engineering, emphasizing the electro-osmosis method. It covers the importance, basic processes, methods, and results of dewatering while highlighting the suitability of various techniques for different soil types. Additionally, it addresses challenges in water management and disposal related to dewatering practices.

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