fiat lux university of liverpool school of engineering year 1 laborato
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FIAT LUX
UNIVERSITY OF
LIVERPOOL
SCHOOL OF ENGINEERING
Year 1 Laboratories
GSD
Grain Size Distribution Test
CIVE120: Geomechanics 1
Lecturer:
Dr Paul Shepley
Demonstrator Name:
Demonstrator Email: UNIVERSITY OF
LIVERPOOL
Health and safety
GSDLab Script // CIVE120
Instructions by lab demonstrators should be followed exactly and information regarding the
labs fire instructions made known. Lab coats must be worn at all times during the
experiment. This lab requires steel capped boots.
You are reminded that you are required by law to comply with the School's basic rules of lab
safety, as outlined at the start of the first year.
1 UNIVERSITY OF
LIVERPOOL
1
Aims and objectives
GSDLab Script // CIVE120
1.1 Aims
This laboratory experiment aims to help students understand how to determine the grain
size distribution of soils.
1.2
Objectives
Prepare samples and measure the grain size distribution of soils.
At the end of this lab experiment, students should be able to:
•
Conduct sieve analysis to determine and plot the grain size distribution of coarse-
grained soils
Describe the textural composition of the soil
2
Theory
Because soils are a naturally occurring material, as engineers we must have established and common
ways to describe and characterise materials found on sites. These will inform other engineers
relying on the material to perform as anticipated, as well as contractors who are working on site to
confirm the material is the material the design was intended for.
At a basic level, soil description involves describing the material as it is found without using tools or
equipment. But if soil samples are taken to the laboratory, one simple test to consider is to
determine the particle size distribution of the sample. This is typically done for coarse-grained
materials using the sieve shaker equipment shown in Figure 1.
SIEVE SHAKER
GORDIVINGAL
QUMENT
Figure 1 - Sieve shaker equipment and wire cloth sieves
2 2.1
UNIVERSITY OF
LIVERPOOL
Particle size distribution analysis
GSDLab Script // CIVE120
This is to determine the proportion of different particle sizes within a soil to determine how
'sorted' - or single-sized – the material is. This is done with around 500g of dry, loose soil.
Let M; be the mass of soil retained on the ith sieve from the top of the nest of sieves and M
be the total soil mass. The percent weight retained is
Mi
M
Retained on ith sieve
==
The percent finer is
× 100%
-
Finer than ith sieve = (1 − Σ=1) × 100%
M
You can use weight instead of mass if you wish – but be confident with your units.
3
Experimental procedure
You will determine the particle size distribution for two materials during this laboratory.
Note - these are the same materials you will/have used during the PMB soil permeability laboratory.
For the method, follow the procedure as:
1) Record the mass of the soil sample
2) Record the mass of the empty sieves
3) Stack sieves in order from smallest to largest, starting at the bottom, with the pan
below the smallest sieve
4) Add the soil sample to the top sieve
5) Tighten the equipment to ensure that the sieve stack is held firmly in the shaker
assembly
6) Set the sieve shaker to vibrate for 15 minutes
7) Take a few minutes to handle the dry soil provided and write a soil description for the
sand. A BS5930:1999 chart has been provided to help you describe the material. Note
the material type, colour and another other points of interest.
8) Determine and record the mass of the sieves with the retained soil
9) Repeat the test with the alternative soil type
4
Result recording
Tabulate your results in the following tables.
3 UNIVERSITY OF
LIVERPOOL
Soil 1 description:
GSDLab Script // CIVE120
Sample mass:
g
Sieve size
(mm)
Empty sieve
mass (g)
Sieve + soil
mass (g)
Mass of soil
retained (g)
Percent
retained (%)
Soil 2 description:
Sample mass:
g
Sieve size
(mm)
Empty sieve
mass (g)
Sieve + soil
mass (g)
Mass of soil
retained (g)
Percent
retained (%)
Cumulative
percent
retained (%)
Percentage
finer (%)
Cumulative
percent
retained (%)
Percentage
finer (%)
4