Compaction of soil

soil compaction
Presentation By-
Vivek Prakash Mani
M Tech, Geotechnical Engineering
Indian Institute of Engineering Science and Technology
Shibpur, Howrah

Table of Content
Compaction
Introduction
Method of Compaction
Laboratory Tests
Deep compaction
Introduction
Different technique adopted
Precompression
Explosion
Heavy Tamping
Compaction Grouting
References 2

Definition
Reduction in Void ratio of soil by mechanical modification
Increase in dry density of soil.
Advantage
Increase in Bearing strength/load carrying capacity
Increase in Shear strength
Reduction is permeability
Provide stable/level surface for construction

Method of Compaction
 Dynamic/Impact loading
 Kneading
 Static/Pressure
 Vibration

Laboratory Tests
 Standard Proctor Test
 Modified Proctor Test

Standard Proctor Test
Apparatus
Compaction Mould (945ml)
Hammer
Mixing Pan
Measuring Jar

Sample Preparation
Collection of soil
Sieved through 4.25mm
Addition of water

Data to be collected
Weight of Empty mould without collar
Weight of mould without collar after compaction of sample
Moisture content
Calculation
Bulk unit weight and Dry Density calculated

Graphical Representation of Observed data
MDD- Max. Dry Density
OMC- Optimum Moisture Content

Factors affecting Compaction
 Water Content
 Compaction Effort
 Method of Compaction
• Mode Of Operation
• Time
• Area of Contact
 Types of Soil
 Area of compaction
 Thickness of layer
11

Introduction
 Densification of deep soil deposit.
 Acquired when requirement of performance criteria is not fulfilled at site
for a given loading condition. OR
 Excess of settlement is taking place or prone to condition like liquefaction.

Different technique adopted
1. Precompression
2. Explosion
3. Heavy Tamping
4. Vibration
5. Grouting

1. Precompression
Categorized under hydraulic modification
Depend upon hydraulic characteristics of the soil.
Involves preloading of soil by means of surcharge for a suitable
duration of time or Lowering of water table so that consol. Can occur
on an accelerated rate.
Reserved for cohesive type of soil.
Long-term process unless the drainage is supplemented by
installations like Sand drains, Paper wicks and Geo-composites drains
etc.
Preloading reduces settlement and Sand drains accelerates settlement

Preloading with Vertical Sand Drains

2. Explosion
Explosives are detonated either on the causing loose soil structure to
collapse and leading to dense rearrangement of particles over a
period of time surface or in an array of Boreholes.
used for modification sand, loose rocks and special soil like loesses
hving a diff. soil skeleton and relatively high porosity.
In sat. soil temp. high p.w.p may set up causing liquefaction.
Care must be taken that structures adjacent to blasting site must not
get affected.

3. Heavy Tamping
densifying soils at significant depths by applying a large impact energy at
the ground surface.
Large mass is dropped in to the ground surface causing compaction. The
process is also termed as dynamic compaction.
Suitable for loose sand deposits.
 performed in predetermined grid pattern.

Advantages of Dynamic compaction:
 Compacts large areas of loose granular fills.
 Reduces the volume of landfill waste.
 Increases in situ density and the voids are collapsed.
 Increased bearing capacity.
 Reduces post-construction settlements.

4.Vibration
Densification is achieved by Vibrating probe or pile aided by water jet or
pressurized air. suitable for free draining cohesionless soil.

Positive Features
 Fast and economical process
 Method allows to utilize standard shallow footings
 Result of compaction can easily be checked
 Noise and vibration level are low
 Environmental friendly as natural and in situ martials are used
 Can be carried out to almost any depth
 Suited to soil profiles with a high water table

Application
 Liquefaction mitigation
 Sinkhole remediation
 Deification of embankment zones and excavation bases to reduce
permeability

5.Compaction Grouting
Zero slump mortar injected in to the soil under high pressure an thus
displacing and compacting surrounding soil.
Types of Compaction Grouting
 Penetration Grouting
Displacement Grouting
 Compaction Grouting
 Grouting of Voids
Jet Grouting

Typical Application of Grouting

29
References
 Engineering Principles of Ground Modification by Manfred R Hausmann
 https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/soil-
compaction
 https://www.geoengineer.org/storage/education/67/general_file_collection/7627
/1557731325-Compaction-Sivakugan.ppt
 https://www.slideshare.net/DrAbdulmannanOrabi/lecture-5-soil-compaction-
67797618
 https://www.google.com/url?sa=i&url=https%3A%2F%2Fcivil-engg-
world.blogspot.com%2F2012%2F10%2FHow-Precompression-Compaction-
Foundation-
Soil.html&psig=AOvVaw2K8a28yOVNTwlM3ngC2JZ1&ust=1605757934817000&sou
rce=images&cd=vfe&ved=2ahUKEwiC39XLmIvtAhWv9DgGHWUgDY0Qr4kDegUIAR
CnAQ
 https://www.sciencedirect.com/topics/engineering/dynamic-compaction
 https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.keller.co.uk%2Fexp
ertise%2Ftechniques%2Fdynamic-
compaction&psig=AOvVaw3nt2Vsf7GXdAJjtn7ZEyKG&ust=1605758076774000&sou
rce=images&cd=vfe&ved=2ahUKEwjtmK6PmYvtAhV3_TgGHTnJDP4Qr4kDegUIARCl
AQ

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