2. submitted to: Col. Naveed HASSAN
Index
Sr no. Topic Page no.
1 Permeability 1
2 Role of permeability 3
3 Significance 4
4 Permeability meter 6
5 Types of permeameters 8
6 Methods of testing permeability 8
7 Uses of permeameter 9
8 Industrial and laboratory methods 11
9 Falling head method 13
10 Constant head method 15
11 Comparison of both 19
12 Apparatus Functioning 23
13 Apparatus Design 27
14 Materials Used 29
15 Components of Apparatus 30
16 Photos 33
17 Expenditure Bill 34
18 Syndicate Personnel 35
19 Working Teams 36
3. Permeability
Definition:-
“Permeability or hydraulic conductivity (k) is a property of a material
that describes the ease with which fluids (such as water)can move
through pore spaces or fractures”.
Explanation:
The permeability of a substance is a measure of the resistance to the
flow a fluid. If it takes high pressure to squeeze a fluid through a
substance, the material is said to have low permeability and vice versa. It
has the units of length per unit time.It is often represented by the
permeability coefficient (k) through the Darcy’s equation:
v =k × i
Where, v is the apparent fluid velocity through the medium, i is the
hydraulic gradient , and k is the coefficient of permeability (hydraulic
conductivity) often expressed in m/s.
This property is necessary for the calculation of seepage through earth
dams or under sheet pile walls, the calculation of the seepage rate from
waste storage facilities (landfills, ponds, etc.), and the calculation of the
rate of settlement of clayey soil deposits. Permeability depends on the
intrinsic permeability of the material, the degree of saturation, and on the
density and viscosity of the fluid.
EXAMPLE:-
Permeability is a very important property and used in many processes. In
casting, the permeability of the sand used is the measure of how well it
allows the gasses to pass through it during ventilation. Impermeable
4. sand allows very little gas to escape. The more permeable the soil the
greater the seepage.
Role of permeability in different industries
Introduction:-
The concept of permeability is of importance in many processes
including the determination of flow characteristics of hydrocarbons in
oil and gas reservoirs and the flow characteristics of ground water in
aquifers. Apart from geology the concept also has many practical
applications in chemical engineering i.e., filtration and in permeable
paving that may be included in the list of applications in civil
engineering.
Applications
Permeable Paving:-
Permeable paving is a range of sustainable materials and techniques for
permeable pavements with a base and subbase that allow the movement
of stormwater through the surface. In addition to reducing runoff, this
effectively traps suspended solids and filters pollutants from the water.
Permeable paving surfaces have proved to be efficient in managing the
run-off from paved surfaces. In new suburban growth, they prevent
water sheds and in existing settlements, redevelopment provides
5. opportunities to implement storm water management practices.
Moreover it reduces the impacts on water quality. This method is being
implemented in the United States.
Permeability and Agriculture:-
In agricultural terms, permeability helps in determining the amount of
water soaked in by the soil- whether rainfall soaks into the ground or
runs off to the nearest stream. If the soil is not permeable and allows
water to stay on its surface, it will affect plant growth. Water
management techniques should be applied to avoid water-logging of
agricultural soils. Controlled traffic and zero tillage are the best ways to
reduce surface accumulation of water. Improving water entryways and
water storage techniques near the field are also good practices to reduce
the effect of water-logging on crops. Cover crops have helped farmers
and agriculturists to improve permeability of soil and reduce soil surface
strength as well.
Oil and Gas Extraction:-
Hydrocarbons - crude oil and natural gas - are found in certain layers of
rock that are usually buried deep beneath the surface of the earth. In
order for a rock layer to qualify as a good source of hydrocarbons, it
must meet several criteria with permeability of the rock being one of the
many important factors.
Another characteristic of reservoir rock is that it must be permeable.
That is, the pores of the rock must be connected together so that
6. hydrocarbons can move from one pore to another. Unless hydrocarbons
can move and flow from pore to pore, the hydrocarbons remain locked
in place and cannot flow into a well which creates a hurdle during the
extraction process.
Aquifers, Soil and Ground Water:-
Generally, soil refers to the top few feet of the land surface. The soil
acts as a natural filter to screen out many substances that mix with the
water. But water will transport some contaminants into theground
water. The amount of groundwater recharge, storage, discharge, as well
as the extent of groundwater contamination, all depend on the soil
properties one of which is the permeability of the soil.
Soil is a mixture of three soil separates:
sands (the coarsest)
silts
clays (the finest)
Classification of these separates is based on grain size.
The size of pore space and thee inter connectivity of the pores help
determine the permeability. The property is also increased by the
uniformity in the grain size. Water can move between the pore spaces.
The larger the pore space, the greater is the permeability allowing water
to move faster through the pores. This is why clay having a fine
structure and poor connectivity off the grains has a low permeability
creating confining layers in the subsurface.
Significance of permeability
Soil Permeability is the property of the soil to transmit water and air and
is one of the most important qualities of soil to consider.
Why knowledge of permeability of soil is important? The answer lies in
its significance in the following engineering problems:
7. Seepage through earthen dams and canals.
Unfit pressure under hydraulic structure and safety against piping.
Rate of settlement of a saturated compressible soil layer.
Yield from a well and drainage of water logged agricultural land.
Stability of upstream and downstream slopes of dams.
Fish culture.
Choosing proper sand for casting in Foundry Work.
The details of some of above problems are mentioned below:
Fish Culture:
A pond built in impermeable soil will lose little water through seepage.
The more permeable the soil, the greater the seepage. Some soil is some
permeable and seepage is so great that it is not possible to build a pond
without special construction techniques. Soils are generally made up of
layers and soil quality often varies greatly from one layer to another.
Before pond construction, it is important to determine the relative
position of the permeable and impermeable layers. The design of a pond
should be planned to avoid having a permeable layer at the bottom to
prevent excessive water loss into the subsoil by seepage.
Slopes of Dams:-
The slopes of Dams should be built in such a manner that will ensure a
good water retention. Again, soil permeability will have to be checked
with this in mind.
Choiceof proper sand for sand casting:-
To ensure the formation of a proper Article through casting process and
to avoid errors(like blow holes, pin holes and Cavitation), it is necessary
for the casting sand to possess some sort of “ventilation”. This is
8. achieved by choosing a casting sand having appropriate value of
permeability.
Permeameter
“It is a device which is used to check the permeabilityor coefficient of
permeability (measure of how easily a soil allows fluids to pass through
it )of a medium”.
If we look at the sand through a microscope there are spaces between the
sand particles like sponge.So the sand allows the fluids to pass through it
and hence we check the permeability of soil. It is a cylinder(tank) in
which the soil sample is placed and has inlet and outlet valves to connect
manometers and to allow the in flow and out flow of water to check the
permeability of a given soil sample.
Types of permeameters
Air Pressure Permeameter
Digital Permeameter
Constant Head Permeamter
Falling Head Permeameter
Magnetic Permeameter
ElectronicPermeameter
Methods of Testing Permeability
9. Finding the permeability of sand can be achieved in many ways. The
techniques vary based on the type of sand being used, accuracy of result
and time required for the test. The permeability of sand can be tested
with the help of:
Pressurized Air
Constant Pressure Water Supply
Electricity
Horizontal TestingMethods:-
These testing methods require the columns of sand to be tested to be
kept in a horizontal position. Gravity and falling resources do not take
part in these types of permeability tests.
The horizontal testing methods include:
1. Air PressurePermeameter:-
In this method pressurized air with the help of fans and exhausts
is created around a horizontal sand column.
Time is noted for the air to pass through the column and
calculations are made accordingly.
This method is used for very finely grained sand and heavy
ramming of sand is required.
2. Digital Permeameter:-
This special permeameter uses electricity of controlled voltages
to help find the permeability of sand.
10. A Menard probe is inserted into a horizontal column of
compressed sand which measures the electric field strength of
the sparks at different locations of the sand column.
This information is then graphed and calculated with the help of
computers and permeability is found.
This method although expensive gives accurate readings for both
coarse and finely grained sand.
Vertical TestingMethods:
Vertical testing methods are the processes in which the column of sand
is set vertically and water is passed through the column. The pressure of
the water column is found at various parts using manometers. In these
experiments water is entered from the top and drained from the bottom
of the column.
There are two main types of vertical testing methods:
1.FallingHead Permeameter:-
Compact the sample in the lower chamber section of the
Permeameter, in layers approximately 1.5 cm deep, to within
about 2 cm of the lower chamber rim. Use an appropriate
ramming device to compact the sample to the desired density.
Water is pushed from the top at constant flow and the initial
“Head” reading is taken from the manometer.
The fall in the head is noted after 2 hours and calculations are
made accordingly.
This method is easier and cheaper as only 1 manometer is used.
11. It can give accurate readings for coarse river sand and is quicker
than the other methods.
2.ConstantHead Permeameter:-
This is again a vertical testing method but in this case water of
constant pressure is used to pass through the sand sample and
two manometers are used.
The water is allowed to fully soak the sand manometer readings
are taken once a constant flow of water through the sample has
been achieved.
The differentials in height of the upper and lower manometer as
well as the time taken for the water to pass through it are the
main readings for this experiment.
This method is more feasible as it gives accurate readings of a
large variety of sand easily and relatively quickly.
This is the purpose of our Project.
Uses of Permeameter
Permeameteris used to determine whether or not the soil content of
a specific area of land may be suitable for a wastewater treatment
system, by testing the permeability of the ground around where the
system would be placed.
Permeameter is used in instances where the amount of
electromagnetic permeability of natural substances such as iron
may be identified to determine whether or not they are suitable for
commercial use.
A permeameter may be used in a number of different applications
where the user needs to know different aspects of the elements
12. underneath a specific surface. For instance, a permeameter may be
used to inform a user in the construction field exactly how
permeable a certain section of concrete is. The higher the level of
allowed permeation by any liquid substance, the weaker the piece
of concrete is.
Permeameters may also be used to check the permeability of
different roadway surfaces to ensure that the materials being used
to construct the roadways are suitable. Surfaces that allow water or
other fluids to seep them and possibly wash out soil under them
can lead to dangerous sinkholes and basins.
Permeameter can be used in is determining soil compaction. This
is used to determine whether a specific ground area is suitable for
construction. It is important to know the permeation level of the
soil or clay and whether its conducive to shifting or washing out
with the introduction of water.
There are a number of uses for the different types of permeameters,
however the two main functions are to measure the amount of
electromagnetic permeability in different soil components and to
determine soil compaction for suitability for construction.
While making artificial pond the permeability is a very important factor.
Soils are generally made up of layers and soil quality often varies
greatly from one layer to another. Before pond construction, it is
important to determine the relative position of the permeable and
impermeable layers. The design of a pond should be planned to avoid
having a permeable layer at the bottom to prevent excessive water loss
into the subsoil by seepage.
Industrial and laboratory methods
13. Laboratory Methods:-
1) Constanthead Permeabilitytest:-
The constant head permeability test is a common laboratory testing
method used to determine the permeability of granular soils like sands
and gravels containing little or no silt. This testing method is made for
testing reconstituted or disturbed granular soil samples.
2) FallingheadPermeabilitytest:-
The falling head permeability test is a common laboratory testing
method used to determine the permeability of fine grained soils with
intermediate and low permeability such as silts and clays. This testing
method can be applied to an undisturbed sample.
The falling head permeability test involves flow of water through a
relatively short soil sample connected to a standpipe which provides the
water head and also allows measuring the volume of water passing
through the sample. The diameter of the standpipe depends on the
permeability of the tested soil. The test can be carried out in a Falling
Head permeability cell or in an oedometer cell.
FieldMethods:-
1) Pumping out tests
2) Pumping in test
The purpose of pumping test is to get the information of permeability;
pumping test is the active way to get k, the permeability. The principle
of a pumping test is that if we pump water from a well and measure the
discharge of the well and the drawdown in the well and in piezometers at
14. known distances from the well, we can substitute these measurements
into an appropriate well-flow equation and can calculate the hydraulic
characteristics of the aquifer
The well will consist of an open-ended pipe, perforated or fitted with a
screen in the aquifer to allow water to enter the pipe, and equipped with
a pump to lift the water to the surface. A pumping test does not require
expensive large-diameter wells. If a suction pump placed on the ground
surface is used, as in shallow watertable areas, the diameter of the well
can be small. A submersible pump requires a well diameter large enough
to accommodate the pump. The well should be drilled to the bottom of
the aquifer, if possible, because this has various advantages, one of
which is that it allows a longer well screen to be placed, which will
result in a higher well yield. The well should be developed by being
pumped at a low discharge rate. When the initially cloudy water
becomes clear, the discharge rate should be increased and pumping
continued until the water clears again. This procedure should be repeated
until the desired discharge rate for the test is reached.
Pumping in test is conducted irrespective of the position of water table
in the stratum, whilethepumping out test is suited for the test below the
water table. The water table is the level to which underground water will
raise in a soil and will be at atmospheric pressure.
The pumping in test is suitable for low permeability and thin strata
where adequate yield may not be available for pump out test. By this
test, permeability of a soil at the bottom of the bore hole is obtained.
Thus this is recommended for permeability determination of stratified
deposits and, hence, to check the effectiveness of grouting in such
deposits.
IndirectMethods:-
1) Computationfrom the particlesize
15. 2) Computationfrom consolidationtest
Falling Head Method
Procedure:-
The following steps are to be done:
Compact the sample in the lower chamber section of the
Permeameter, in layers approximately 1.5 cm deep, to within about
2 cm of the lower chamber rim. Use an appropriate tamping device
to compact the sample to the desired density.
Remove the upper section of the chamber tie rods and place the
upper porous stone on the specimen, securing the upper section of
the chamber with spring to the unit.
Measure and record the length of the specimen.
Use the clamp to attach the falling head burette to the support rod.
Position the burette as high as is possible for practicality. Place the
meter stick directly behind the burette, so the height of water in the
burette above the chamber outflow port may be read.
Saturate the specimen, following the steps outlined above.
Measure the heights of the two levels from the outflow level.
After a stable flow has been established, note the drop in head (Δh)
in 2 hours. (use a stop watch).
EQUATION TO BE USED:-
K =
𝑨𝒍
𝑨𝒕 𝒍𝒏(𝒉𝟎/𝒉𝟏)
Where,
K = Coefficient of permeability
a = Area of the burette
L = Length of soil column
A = Area of the soil column
h0 = Initial height of water
16. h1 = Final height of water = h0 - Δh
t = Time required to get head drop of Δh
17.
18. CONSTANT HEAD METHOD
Standards:-
ASTM D2434 - 68(2006)Standard Test Method for Permeability of
Granular Soils (Constant Head)
Equipments:-
Permeameter
manometers
constant head tank
constant-head-tank stand
porous screen
compaction equipment such as a rammer
stop watch
graduated cylinder
funnel
thermometer
weighing balance
pan for keeping sand sample
Theory:-
The constant-head method allows water to move through the soil under a
steady state (constant head) condition while the quantity (volume) of
water flowing through the soil specimen is measured over a period of
time. By knowing the quantity Q of water measured, length L of
specimen, cross-sectional area A of the specimen, time t required for the
quantity Q of water to be discharged, and head h, the
permeability(hydraulic conductivity) k can be calculated as:
𝒌 =
𝑸𝑳
𝑨𝒉𝒕
19. Procedure:-
Measure the initial mass of the pan along with the dry soil (M1).
Remove the cap of the permeameter and measure the inside diameter
of upper and lower chambers. Calculate the average inside diameter
of the permeameter (D).
Using a funnel, pour the soil into the lower chamber using a circular
motion to fill it until the soil sample is 1.5 cm below the upper
manometer valve.
Measure the final mass of the pan along with the dry soil (M2).
Use the tamping device to compact the layer of soil.
Level the top surface of the soil and place the upper porous screen on
it.
Place the compression spring on the porous screen and replace the
cap.
Measure the sample length at four locations around the
circumference of the permeameter and compute the average length.
Record it as the sample length.
Connect the gas tube from the outlet of the constant head tank to the
inlet of the permeameter and keep the inlet valve of the permeameter
closed.
Open the inlet valve of the constant head tank.
Place tubing from the overflow outlet of constant head tank to the
sink to collect any water that may come out.
As soon as the water begins to flow out of the overflow valve, open
the inlet valve to permeameter.
Keep outlet valve closed for some time and then open it when
equilibrium inside the permeameter established.
Allow adequate time for the flow pattern to stabilize.
Measure the time it takes to fill a volume of 750 - 1000 ml using the
graduated cylinder, and then measure the temperature of the water.
Measure the vertical difference between the two heads of
permeameter and record the distance as h.
Calculate the permeability,using the following equation:
20. 𝒌 =
𝑸𝑳
𝑨𝒉𝒕
Where:
k= coefficient of permeability at temperature T, cm/sec.
L = length of specimen in centimeters
t = time for discharge in seconds
Q = volume of discharge in cm cube (1 ml = 1 cm cube)
A = cross-sectional area of permeameter
h = hydraulic head difference between manometers, in cm.
The viscosity of the water changes with temperature. As
temperature increases viscosity decreases and the permeability
increases. The coefficient of permeability is standardized at 20°C,
and the permeability at any temperature T is related to K20 by the
following ratio:
K20 = kt (nt / n20)
Where, ηt and η20 are the viscosities at the temperature T of the test and
at 20°C, respectively.
Compute the volume of soil used from: V = LA.
Compute the mass of dry soil used in permeameter:
M = initial mass - final mass= M1-M2
Compute the dry density (ρd) of soil
ρd = M/V
22. The knowledge of this property is much useful in solving problems
involving yield of water bearing strata, seepage through earthen dams,
stability of earthen dams, and embankments of canal bank affected by
seepage, settlement etc.
Planningand organization:-
1: Preparation of the soil sample for the test2: Finding the discharge
through the specimen under a particular head of water.
Definitionof co-efficientof permeability:-
The rate of flow under laminar flow conditions through a unit cross
sectional are of porous medium under unit hydraulic gradient is defined
as coefficient of permeability.
Equipment:-
1. Permeameter mould of non-corrodible material, with an internal
diameter and internal effective height.
2. The mould shall be fitted with a detachable base plate and removable
extension counter.
3. Drainage bade: A bade with a porous disc, with some specified
thickness which has the permeability 10 times the expected permeability
of soil.
4. Drainage cap: A porous disc having a fitting for connection to water
inlet or outlet.
5. Constant head tank: A suitable water reservoir capable of supplying
water to the permeameter under constant head.
6. Graduated glass cylinder to receive the discharge.
7. Stop watch to note the time.
8. A meter scale to measure the head differences and length of specimen.
Test procedure:-
23. 1. For the constant head arrangement, the specimen shall be connected
through the top inlet to the constant head reservoir.
2. Open the bottom outlet.
3. Establish steady flow of water.
4. The quantity of flow for a convenient time interval may be collected.
5. Repeat three times for the same interval.
Fallingheadmethod:-
Objective:-
To determine the coefficient of permeability of the given soil sample,
using falling head method.
Need and Scope:-
The test results of the permeability experiments are used:
1. To estimate ground water flow.
2. To calculate seepage through dams.
3. To find out the rate of consolidation and settlement of structures.
4. To plan the method of lowering the ground water table.
5. To calculate the uplift pressure and piping.
6. To design the grouting.
7. And also for soil freezing tests.
8. To design pits for recharging.
The falling head method of determining permeability is used for soil
with low discharge, where as the constant head permeability test is used
for coarse-grained soils with a reasonable discharge in a given time. For
very fine-grained soil, capillarity permeability test is recommended.
Principleof the experiment:-
24. The passage of water through porous material is called seepage. A
material with continuous voids is called a permeable material. Hence
permeability is a property of a porous material which permits passage of
fluids through inter connecting conditions.
Hence permeability is defined as the rate of flow of water under laminar
conditions through a unit cross-sectional area perpendicular to the
direction of flow through a porous medium under unit hydraulic gradient
and under standard temperature conditions.
The principle behind the test is Darcy’s law for laminar flow. The rate
of discharge is proportional to (i x A)
q= kiA
where q= Discharge per unit.
A=Total area of c/s of soil perpendicular to the direction of flow.
i=hydraulic gradient.
k=Darcy’s coefficient of permeability =The mean velocity of flow that
will occur through the cross-sectional area under unit hydraulic gradient.
Planningand organization:-
The tools and accessories needed for the test are:
1.Permeameter with its accessories.
2.Standrd soil specimen.
3.Deaires water.
4.Balance to weigh up to 1 gm.
5.I.S sieves 4.75 mm and 2 mm.
6. Mixing pan.
7.Stop watch.
8.Measuring jar.
9.Meter scale.
10.Thermometer.
11.Container for water.
12. Trimming knife etc.
Knowledge of equipment:-
1. The permeameter is made of non-corrodible material, with an
internal diameter and effective height. The mould has a
detachable base plate and a removable exterior collar.
25. 2. The drainage base is a porous disc, with a specified thickness
with a permeability 10 times that of soil.
3. The drainage cap is also a porous disc of specified thickness with
an inlet/outlet fitting.
4. The container tank has an overflow valve. There is also a
graduated jar to collect discharge.
5. The stand pipe arrangements are done on a board with 2 or 3
glass pipes of different diameters.
Test Procedure:-
1. Prepare the soil specimen as specified.
2. sturate it. Deaired water is preferred.
3. assemble the permeameter in the bottom tank and fill the tank
with water.
4. Inlet nozzle of the mould is connected to the stand pipe. Allow
some water to flow until steady flow is obtained.
5. Note down the time interval tfor a fall of head in the stand pipe
h.
6. Repeat step 5 three times to determine t for the same head.
7. Find a by collecting q for the stand pipe. weight it correct to 1
gm and find a from q/h=a.
Apparatus Functioning
The first component of our apparatus is our reservoir which is used to
store water which then would be used to check the permeability of the
given sand.The reservoir acts as a storage tank and water is filled into
the reservoir through an inlet which is connected to some water source.
Our permeability meter is “Constant Head Permeability Meter” so for
this meter the level of water must be kept constant inside the reservoir.
The water continuously flows into the reservoir and incase of overflow
26. we have another outlet which will allow the water to flow out of the
reservoir so that the level of water inside the reservoir is kept constant.
From the reservoir the water through an outlet flows into a pipe which
carries this water into the main part of our apparatus i.e the sand
permeameter .The reservoir is placed on a stand which is a feets high
and allows the water to flow easily from the reservoir to the
permeameter. As water flows from an area of high pressure to low
pressure so that’s why the stand is used. The water flows from the
reservoir to the permeameter. The permeameter is completely filled with
sand. In the permeameter we have circular wire meshes which do not
allow the sand to go below a certain height. At the top of the sand a
spring is placed which applies pressure on the sand and does not allow it
to expand when water flows through it. When the water enters the
permeameter it flows through the sand. The amount of water flowing
through the sand will tell us about its permeability. It flows through the
sand and passes through the wire mesh from where it flows it from an
outlet. On the permeameter we have 2 valves and 2 outlets. One of the
valve is used to make the water flow through the permeameter while the
other Is used to make it flow out of the permeater. While the two outlets
are connected with the two tubes of the manometer. The manometer tell
the pressure difference between the top and bottom the permeameter this
pressure difference will help us calculate the permeability of the given
sand. The manometer is attached on a woddenstand. The two tubes of
the manometer are attached to the sand permeameter with the help of
pipes. The stand is made up of lasani wood. A graduated cylinder is used
for calculating amount of water flowing through an outlet from sand
permeameter. Wooden stand used for giving support to manometer is
made of lassani artificial wood. Wooden stand is painted with brown
paint as brown colour is standard colour for wood. Paint is done so that
wood can be saved from external effects and microorganisms. Paint
saves it from damage. Iron stand used for giving height to reservoir is
made from mild steel and is coloured black as standard colour of iron is
black. This paint saves stand from corrosion and arc welded area from
27. oxidation. Arc welding is done to join the assembly of mild steel
material for preparing the stand. Its height is set so that a sufficient
pressure can be given to the water to flow into the sand permeameter.
Reservoir has three holes. One for outlet to sand permeameter and other
two for overflow and supply of water. Manometer used for measuring of
pressure works when due to difference of water level is caused due to
difference in pressure which it measures. Rubber tubes are used for the
purpose of water supply because it is economical and better flow of
water. Lasani wood is used for making the stand because it is best for
making a stand due to its better strength. Silicon is used in joining the
wire mesh with sand permeameter because its adhesion or joining
strength is too much and it does not allow the sand to move through
sides. Same silicon is used for joining spring with cap of sand
permeameter. Stop watch will also be used so that time for the flow of
definite amount of water could be calculated.
30. There are 3 major components of the permeability meter which include:
1. Manometer tubes
2. Reservoir
3. Cylinder
The detailed study of these is as follows:
1. Manometer:-
A manometer is an instrument that uses a column of liquid
to measure pressure, although the term is currently often used to mean
any pressure measuring instrument.
Because pressure was once commonly measured by its ability to
displace a column of liquid in a manometer, pressures are often
expressed as a depth of a particular fluid (e.g. inches of water).
Manometric measurement is the subject of pressure head calculations.
The most common choices for a manometer's fluid are mercury (Hg) and
water; water is nontoxic and readily available, while mercury's density
allows for a shorter column (and so a smaller manometer) to measure a
given pressure. The abbreviation "W.C." or the words "water column"
are often printed on gauges and measurements that use water for the
manometer.
In our Sand permeability meter, two glass tubes have been attached to a
wooden stand i.e. manometer wooden stand. . These are connected with
the cylinder. The working principle is that water goes into the cylinder
from the reservoir and after passing through the sand, into the
manometer tubes.
In our Sand permeability meter, we are required to calculate ‘Pressure
difference’ between the two glass tubes installed. This pressure
difference would be given by the difference in the heights of water
columns in the two tubes. The tube connected with the lower outlet of
31. cylinder will have more pressure of water column and thus more height.
This height or pressure difference thus calculated is then used in the
formula of determining permeability constant.
Manometer is made up of two glass tubes each having a length of 2.5ft.
These are clamped on a wooden board of length 3ft 2inches. This
wooden board is joined on another base made up of wood having a
length of 40 inches. A slot had been made in the base of 15 inches in
which the board had been fixed using a support. This is the simple
arrangement and the functioning of the manometric tubes.
2. Reservoir:-
“Reservoir is in literal meanings a water storing device or tank.”
The reservoir of this instrument also contains water which is then used
to check the permeability of the sand. It is basically a large storage of
water placed at the top most place so that water flows down in the
cylinder from it if it is on the same level as the other apparatus then
water will not flow. Torricellis Law is used here. There are 3 orifices in
the reservoir. There function is as follows:
Top: Excess water outlet valve. The excess water is removed from this
orifice.
Middle: Inlet valve. Through this orifice water is filled in the reservoir.
Bottom: Cylinder outlet valve. Through this orifice the water enters the
cylinder.
Gas valve's are connected at these orifices. Gas pipes are used to carry
water from the reservoir to other places.
The reservoir is places on a Mild steel stand whose length is almost
about 4.5 feet about the surface of the earth.
32. The orifices in the cylinder are made with the help of a drill. At first a
6mm holes was created which was then enlarged to 12mm gradually.
The reason for this was if a direct orifice of 12mm would've been made
then the reservoir might crack.
3. Cylinder:-
Cylinder is the component in which the entire experiment
takes place. It is basically a small cylinder in which there are 4 orifices.
Their function is as follows:
Cap orifice: Inlet valve. Water enters from the reservoir into the
cylinder from this orifice.
Top: It is connected to one of the glass manometer tubes. As it is in the
top hence less water will flow through it hence the water level in the
corresponding tube will be less.
Bottom(without switch): It is connected to the second manometer tube.
As it is at the bottom hence the water pressure will be more by torricellis
law so the tube connected to this orifice will contain higher water level.
Bottom(with switch): It is the outlet valve to remove the water from the
cylinder for the experiment.
Near the bottom of the cylinder two porous metal sheets are placed and
in between them wire mesh is placed. This is the filtering assembly
which does not allow the sand to flow past it. Above it sand is placed
and then another metal sheet is placed. It's purpose is to press the sand
between the desired space. It is pushed with the help of a spring which is
connected to the lid of the cylinder.
Water enters the cylinder form the lid valve and passes through the sand
which is placed on the metal sheets. Water then passes through the wire
mesh and is accumulated at the bottom. From the bottom it flows into
the manometer tubes. It also flows to the other tube of the manometer
33. through the upper valve. When they are filled to the desired level outlet
valve is opened to let the water escape.
This assembly is placed above a wooden stand and is placed below the
reservoir. Beneath this there is a container to accumulate the water
removed whose volume is measure later on.
Material Used
The material and the instruments used in the making of the apparatus
assembly are:-
Mild Steel Rod
Mild steel round sheet
Stainless steel clamps
Angle iron
Plastic container
Plastic Reservoir
Nozzles
Valves
MaleFemales
Wire Mesh
Silicon Seal
Lassani wood
Soft wood
Spray paint
Paint Emulsion
Gas pipes
Teflon tapes
Rubber bases
Glass tubes
34. Clamps
Connectors
Foams
Filter paper
River Sand
Meter Rod
Stop watch
Mass determining device
Graduated cylinder
Photos of the apparatus
Expenditure bills
The following table concludes the expenditure of the above mentioned
constant head permeameter constructed for the workshop project.
Sr
no
Material Quantity Cost Purchasing
place
1 glass tube 2 900/. Hathi chowk
2 container 1 480/. I /10
3 cylindrical
box
1 180/. i/10
4 Kl sheet 1 230/. G-9/1
5 Sprays(black
, brown)
2 300/. G-9/1
6 valves 12 310/. G-9/1
7 Metal rods 4 370/. G-9/1
8 Acrylic sheet 1 600/. saddar
9 paint 1 240/. saddar
35. 10 Wooden piece 3 500/. Saddar
11 Wire mesh 1 300/. Saddar
12 Angle iron 2 kg 140/. G-9/1
13 Round ms
sheet
1 300/. G-9/1
14 Foam and
filter paper
2 130/. Hathi chowk
15 Transport -- 600/. Different
places
16 Miscellaneous
items
4 270/. Sadder,G-9/1,
i-10/1
Total cost = PKR 6800/.
Syndicate Personnels
Syndicate leader: Taimoor Asif
Coordinator: Umair Jamal
Resourceable person: Syed Ali Haider Abidi
36. Working teams
Reservoirand reservoir:-
Leader: Usman Humayun
Taimoor asif
Abdullah Awais
Muhammad Sajawal
Shumail Hassan
Muhammad Usama Zia
Saad Tahir
Manometer stand and cylinder base:-
Leader: Syed Mazhar Abbas Naqvi
Syed Ali Haider Abidi
Muhammad Sohail Omer
Arsal Rauf
Muhammad Ibrahim Quddusi
Muhammad Irtaza Arshad
Zain Ahmed
37. Cylinder(permeameter):-
Leader: Umair Jamal
Osaid Ahmed
Saqib Ali
Muhammad Khizar
Abdul Mannan Fouzi
Saad bin Shariq
Muhammad Fahad Zahid
Finance:-
Syed Ali Haider Abidi
Taimoor Asif
Logistics:-
Leader: Muhammad Irtaza Arshad
Muhammad Usama Zia
Saqib ali
Muhammad Ibrahim Quddusi
Abdul Mannan Fouzi
Publications:-
Leader: Taimoor Asif
