1 laboratory compaction test of soil (1)
Post on 11-Jul-2016
10 Views
Preview:
DESCRIPTION
TRANSCRIPT
GEOTECHNICAL ENGINEERING II (CECE4131)
Course Title: Geotechnical Engineering - 2Course Code: CECE 4131
Level: BaccalaureateCourse Lecturer : Mr. Jayram
Laboratory Technician: MrBoggarapuSrinivas
Experiment - 1Laboratory Compaction Test of Soil
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 1
Student NameStudent ID No.Section No.Group No.Date of Performance
Shinas College of Technology
Department of Engineering
Civil Engineering Section
GEOTECHNICAL ENGINEERING II (CECE4131)
Laboratory Compaction Test of Soil
1.1 ObjectiveThis test will enable the student to determine the relationship between compacted dry density and soil
moisture content, and find out the maximum dry density and optimum moisture content of the soil
sample.
1.2 Need and ScopeSoil placed as engineering fill (embankments, foundation pads, road bases) must be compacted to the
selected density and moisture content to ensure the desired performance and engineering properties
such as shear strength, compressibility, or permeability. Also, foundation soils are often compacted to
improve their engineering properties. Laboratory compaction tests provide the basis for determining
the percentage compaction and moisture content needed in the field, and for controlling construction
to assure that the target values are achieved.
1.3 Standard ReferenceBS 1377 Part 4 Section 3 – Determination of dry density/moisture content relationship using 2.5kg
rammer
1.4 Required Materials and Equipment1.4.1 2.5 kg rammer
1.4.2 Soil compaction machine (optional)
1.4.3 Compaction mould, 1L
1.4.4 BS CBR Mould
1.4.5 BS Test Sieves 63mm, 37.5mm, 20mm
1.4.6 A scale (electronic balance), readable to 0.1g and 1g
1.4.7 Stainless containers
1.4.8 Medium size metal scoop
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 2
GEOTECHNICAL ENGINEERING II (CECE4131)1.4.9 Spatula
1.4.10 Watertight plastics, or polythene bags
1.4.11 Straightedge
1.4.12 Drying Oven 105°C to 110°C
1.4.13 Measuring Cylinder
1.4.14 Wash bottle
1.4.15 Rubber mallet or soil extruder
1.4.16 Mould oil (for slight greasing inside the mould)
Note: A compaction mould of 1L internal volume is used for soil in which all particles pass a 20mm
test sieve. If there is a limited amount of particles up to 37.5mm size, same tests are carried out in the
larger California Bearing Ratio (CBR mould).
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 3
GEOTECHNICAL ENGINEERING II (CECE4131)
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 4
GEOTECHNICAL ENGINEERING II (CECE4131)
1.5 Test Specimen1.5.1 Prepare and subdivide the initial sample by quartering or riffling to get the desired minimum
sample required based on the table below:
Minimum percentage
passing 20mm test sieve
Minimum mass of
prepared soil requiredType of mould used
100% 15kg 1L
70% 40kg CBR
Table 1: Minimum mass of soil required and corresponding mould to be used
1.5.2 Spread the soil sample on a large pan and let it air-dry for at least one day.
1.5.3 Subdivide the initial sample to produce 5 or more representative samples, each of about 2.5kg.
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 5
GEOTECHNICAL ENGINEERING II (CECE4131)1.5.4 Mix each sample thoroughly with a different amount of water to give a suitable range of
moisture contents. The range of moisture contents shall be such that at least 2 values lie either side of
the optimum at which the maximum dry density occurs. The procedures below show how to place
different amount of water in the sample.
1.5.4.1 Calculate how much amount of water to be placed in a 2.5kg mass of soil using 2% by mass.
1.5.4.2 Place the desired water and mix thoroughly with the sample. Visually check the mix sample by
squeezing it into your hand and gently release it. If the soil sticks together and forms a lump, this
means that it is near to optimum moisture content and can be set as sample 3. But if the soil looses
after releasing your hand, meaning you still need to add more calculated water and mix the sample
again, repeating the same procedure. Upon attaining the desired mixture (take note of the amount of
water placed), put the soil sample in an airtight plastic bag.
1.5.4.3 After preparing sample 3, get one of the representative samples and prepare it for sample 1 by
placing 2% in ml of 2.5kg of soil. Mix the sample and place it in an airtight plastic bag.
1.5.4.4 Another sample will be mixed with a calculated amount of water 2% or 4% more than the
amount of water placed in sample 1. Mix the sample and place it in an airtight plastic bag.
1.5.4.5 In preparing for sample 4, place 2% or 4% more water which you had placed in sample 3 in
another sample. Mix and place it in an airtight plastic bag.
1.5.4.6 Lastly, mix the remaining soil sample as sample 5 with 2% or 4% water which you had placed
in sample 4. Mix and place it in an airtight plastic bag.
Note: Leave all mixed samples for about one day.
1.6 Procedure1.6.1 Weigh the mould with base plate attached to 1g (m1).
1.6.2 Determine the inside volume of the mould by measuring the internal dimension to 0.1mm.
1.6.3 Attached the extension to the mould and place the mould assembly on a solid base.
1.6.4 Place a quantity of moist soil (sample 1) in the mould such that when compacted, it occupies a
little over one-third of the height of the mould body.
1.6.5 Apply 27 blows from the rammer by dropping it to the soil using the guide tube. Distribute the
blows uniformly starting from the sides to centre over the surface. Ensure that the rammer always falls
freely and not obstructed by soil in the guide tube.
1.6.6 Repeat 5.6.4 and 5.6.5. As for the last layer, the surface should not be 6mm more of the upper
edge of the mould body.
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 6
GEOTECHNICAL ENGINEERING II (CECE4131)1.6.7 Remove the extension, strike off the excess soil and level off the surface of the compacted soil
carefully to the top of the mould using the straightedge. Replace any coarse particles, removed in the
levelling process and press in well.
1.6.8 Weigh the soil and mould with baseplate to 1g (m2).
1.6.9 Remove the compacted soil from the mould using rubber mallet or soil extruder and place it in a
container. Take a representative sample of about 1kg for moisture content.
1.6.10 Repeat procedures 5.6.1 to 5.6.9 for the rest of the samples. Make sure to clean the mould and
grease it slightly before every use.
Note: Prepare 5 representative of initial sample, 6kg each in using CBR mould.
1.7 Calculations:1.7.1 Calculate for the moisture content of the soil samples.
1.7.2 Calculate the bulk density, ρ (Mg/m3), of each compacted specimen using the formula below.
m2 - m1
V
where:
m1 – is the mass of mould and baseplate, g
m2 – is the mass of mould, baseplate, and compacted soil, g
V – volume of mould with baseplate, cm3
1.7.3 Calculate the dry density ρd (Mg/m3), of each compacted specimen from the equation
100 ρ
100 + w
where:
ρ – is the bulk density, Mg/cm3
w – moisture content, %
1.7.4 Plot the dry densities obtained as Y-axis, and moisture content as X-axis. Draw a curve of best
fit to the plotted points and identify the position of the maximum on this curve. Read off the values of
dry density and moisture content to three significant figures corresponding to that point.
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 7
ρ =
ρd =
GEOTECHNICAL ENGINEERING II (CECE4131)
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 8
GEOTECHNICAL ENGINEERING II (CECE4131)
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 9
GEOTECHNICAL ENGINEERING II (CECE4131)WORKSHEET FOR DETERMINATION OF MAXIMUM DRY DENSITY (MDD) AND
OPTIMUM MOISTURE CONTENT (OMC) OF SOIL using 2.5KG RAMMER
Location Sample No.
Soil Description Date
Test no. 1 2 3 4 5
Mass of mould + baseplate, (m1) g
Mass of mould + baseplate + compacted specimen,
(m2) g
Mould volume, (V) cm3
Mass of compacted specimen, (m2- m1) g
Bulk Density, (ρ), (m2- m1/V) Mg/ m3
Container no.
Mass of container g
Mass of wet soil + container g
Mass of dry soil + container g
Mass of moisture g
Mass of dry soil g
Moisture content, (w) %
Dry Density, (ρd) (100 ρ)/(100+w) Mg/ m3
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 10
MDD (Mg/ m3)
OMC (%)
GEOTECHNICAL ENGINEERING II (CECE4131)
Moisture Content (%)
Worksheet No. 1: Laboratory Compaction Test using 2.5kg Rammer
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 11
Dry
Den
sity
(Mg/
m3 )
GEOTECHNICAL ENGINEERING II (CECE4131)
Shinas College of Technology -Soil Mechanics Lab Semester II (2014-2015) Page 12
top related