STUDENT CODE OF ETHIC
STUDENT CODE OF ETHIC
(SCE)
(SCE)
DEPARTMENT OF INFRASTRUCTURE AND GEOMATIC ENGINEERING
DEPARTMENT OF INFRASTRUCTURE AND GEOMATIC ENGINEERING
FACULTY OF CIVIL &
FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING
ENVIRONMENTAL ENGINEERING
I, hereby confess that I have prepared this report on my own effort. I also admit not
I, hereby confess that I have prepared this report on my own effort. I also admit not
to receive or give any help during the preparation of this report and pledge
to receive or give any help during the preparation of this report and pledge
that everything mentioned in the report is true.
that everything mentioned in the report is true.
_________________
_________________
Student Signature
Student Signature
Name Name : ………: ……… Matric No. : ……… Matric No. : ………Date
:
Date
:
………DEPARTMENT:
DEPARTMENT: INFRASTRUCTURE ANDINFRASTRUCTURE AND GEOMATIC ENGINEERING GEOMATIC ENGINEERING EDITION: EDITION: REVIEW NO.: REVIEW NO.: TEST TITLE:
TEST TITLE: CONSTANT HEADCONSTANT HEAD PERMEABILITY TEST PERMEABILITY TEST EFFECTIVE EFFECTIVE DATE: DATE: 3/01/12 3/01/12 AMENDMENT AMENDMENT DATE: DATE: 3/01/12 3/01/12 1.0 OBJECTIVE 1.0 OBJECTIVE
TO DETERMINE THE PERMEABILITY OF SANDS AND GRAVELS CONTAINING LITTLE OR NO TO DETERMINE THE PERMEABILITY OF SANDS AND GRAVELS CONTAINING LITTLE OR NO SILT.
SILT.
2.0
2.0 LEARNING OUTCLEARNING OUTCOMEOME
At At the the end end of of this this experiment, experiment, students are students are able able to:to:
Describe the procedure to Describe the procedure to determine the determine the coefficicoefficient ent of of permeability of permeability of sands and sands and gravels based gravels based onon BS 1377.BS 1377.
Identify the relationship between Identify the relationship between permeability and permeability and pore pore size of size of the the coarse grained coarse grained soils.soils.
Measure the coeMeasure the coefficient officient of permf permeability eability of sandof sands and s and gravels gravels containing containing little olittle or no r no silt.silt.3
3.0 THEORY.0 THEORY
The most common permeability cell (permeameter) is 75mm in diameter and is intended for sands The most common permeability cell (permeameter) is 75mm in diameter and is intended for sands containing particles up to about 5mm. A larger cell, 114mm, can be used for testing sands containing containing particles up to about 5mm. A larger cell, 114mm, can be used for testing sands containing particles up to about 10mm, i.e. medium gravel size. As a general rule the ratio of the cell diameter to the particles up to about 10mm, i.e. medium gravel size. As a general rule the ratio of the cell diameter to the diameter of the largest size of particle in
diameter of the largest size of particle in significant quantity should be at least 12.significant quantity should be at least 12.
The constant head permeability cell is intended for testing disturbed granular soils which are recompacted The constant head permeability cell is intended for testing disturbed granular soils which are recompacted into the cell, either by
into the cell, either by using a specified compactive effort, or to achieve a certain dry density, i.e. using a specified compactive effort, or to achieve a certain dry density, i.e. void ratio.void ratio. In the constant head test, water is made to flow through a column of soil under the application of a pressure In the constant head test, water is made to flow through a column of soil under the application of a pressure difference which remains constant, i.e. under a constant head. The amount of water passing through the soil difference which remains constant, i.e. under a constant head. The amount of water passing through the soil in a known time is measured, and the permeability of the sample is calculated by using Equation (1).
in a known time is measured, and the permeability of the sample is calculated by using Equation (1). If the connections to the cell are arranged so that water flows upwards through the sample, the critical If the connections to the cell are arranged so that water flows upwards through the sample, the critical hydraulic gradient can be determined after measuring the steady state permeability, and the effects of hydraulic gradient can be determined after measuring the steady state permeability, and the effects of instability (boiling and piping) can be observed. It is important that use only air-free water, and measures for instability (boiling and piping) can be observed. It is important that use only air-free water, and measures for preventing air bubblin
preventing air bubbling out of solution during these tests is g out of solution during these tests is very crucial.very crucial.
q
q
Perm
Permeab
eability,k
ility,k (m /
(m / s)
s)
A
A
ii
(1)(1)
Where: q
Where: q = rate = rate of flow,of flow, A = area of sa A = area of sample,mple,
i
i = = hydraulic gradient,hydraulic gradient,
= =h h 2 2 hh11 L L
hDEPARTMENT:
DEPARTMENT: INFRASTRUCTURE ANDINFRASTRUCTURE AND GEOMATIC ENGINEERING GEOMATIC ENGINEERING EDITION: EDITION: REVIEW NO.: REVIEW NO.: TEST TITLE:
TEST TITLE: CONSTANT HEADCONSTANT HEAD PERMEABILITY TEST PERMEABILITY TEST EFFECTIVE DATE: EFFECTIVE DATE: 3/01/123/01/12 AMENDMENT AMENDMENT DATE: DATE: 3/01/12 3/01/12 4.0 TEST EQUIPMENTS 4.0 TEST EQUIPMENTS 1.
1. Constant head permConstant head permeability cells, fitted with loading piston, pereability cells, fitted with loading piston, perforated plates, flow tube conneforated plates, flow tube connections,ctions, piezometer nipples and connections, air bleed valve, sealing rings. Figure 1 shows permeameter piezometer nipples and connections, air bleed valve, sealing rings. Figure 1 shows permeameter cells that commonly used in laboratory testing.
cells that commonly used in laboratory testing.
Figure 1: Permeameter cells for constant
Figure 1: Permeameter cells for constant head test: head test: (a) 75mm, (b) 114mm(a) 75mm, (b) 114mm (Courtesy of ELE International, 2007)
DEPARTMENT:
DEPARTMENT: INFRASTRUCTURINFRASTRUCTURE E ANDAND GEOMATIC ENGINEERING GEOMATIC ENGINEERING EDITION: EDITION: REVIEW NO.: REVIEW NO.: TEST TITLE:
TEST TITLE: CONSTANT HEADCONSTANT HEAD PERMEABILITY TEST PERMEABILITY TEST EFFECTIVE EFFECTIVE DATE: DATE: 3/01/12 3/01/12 AMENDMENT AMENDMENT DATE: DATE: 3/01/12 3/01/12 5.0 PROCEDURES 5.0 PROCEDURES 1.
1. Prepare Prepare permeameter permeameter cell,cell, a.
a. Remove Remove the the top top plate plate assembly from assembly from the the cell.cell. b.
b. Measure Measure the the following following dimensions:dimensions: i.
i. Mean Mean internal internal diameter diameter (D (D mm),mm), ii.
ii. Distance between Distance between centres centres of of each each set set of of manometer manometer connection connection points points alongalong the axis of the cell (L mm),
the axis of the cell (L mm), iii.
iii. Overall approximate Overall approximate internal internal length length of of cell cell (H(H11 mm), mm),
c.
c. Calculate Calculate the the following following based based on on measured measured dimensions:dimensions: i.
i. Area of Area of cross-section cross-section of of sample, sample, A A ==
DD22/4 mm/4 mm22ii.
ii. Approximate mass Approximate mass of of soil soil required, required, to to fill fill the the permeameter permeameter cell,cell, V = A H
V = A H11/1000 cm/1000 cm33
iii.
iii. Approximate Approximate mass mass of of soil soil requiredrequired, , if if placed placed at at a a densitydensity
Mg/m Mg/m33,,mass =
mass =
A H A H11/1000 g/1000 g2.
2. Select Select sample,sample, a.
a. Air-dry Air-dry the soil the soil which the which the test samptest sample is to le is to be takebe taken.n. b.
b. Sieve the soil Sieve the soil sample and any sample and any particles larger than 5 particles larger than 5 mm need mm need to be to be removed byremoved by sieving.
sieving. c.
c. The material The material needs to needs to be be reduced by reduced by the usual the usual riffling process to riffling process to produce severalproduce several batches of samples each about equal to the mass required to fill the permeameter cell batches of samples each about equal to the mass required to fill the permeameter cell 3.
3. Prepare Prepare sample,sample, a.
a. The sample The sample may be may be placed in placed in the permeameter the permeameter cell by cell by one of one of three methods:three methods: i.
i. Compacting Compacting by by rodding,rodding, ii.
ii. Dry Dry pouring,pouring, iii.
iii. Pouring Pouring through through water,water, 4.
4. Assemble Assemble cellcell a.
a. Place a second Place a second porous disc (if porous disc (if one has one has already been used) already been used) and the and the second wire gauzesecond wire gauze disc on top of
disc on top of the soil, followed by about 40mm thickness of glass the soil, followed by about 40mm thickness of glass balls or gravel filterballs or gravel filter material,
material, b.
b. The leveThe level of the tol of the top surface p surface of the filter of the filter should be should be within the within the limits requilimits required tored to accommodate the top plate,
accommodate the top plate, c.
c. Slacken the Slacken the piston lockipiston locking collar ng collar on the ceon the cell top, pulll top, pull the pistol the piston up as n up as far as it far as it will go,will go, and re-tighten the locking collar,
and re-tighten the locking collar, d.
d. Fit the Fit the cell top cell top on the on the cell and cell and tighten it down tighten it down into place into place by progressively tightening theby progressively tightening the clamping screws,
clamping screws, e.
e. Release the Release the piston locking collar piston locking collar and and push the push the piston down piston down until the until the perforated plateperforated plate bears on the filter material,
bears on the filter material, f.
f. Hold Hold it doit down fwn firmly irmly while while the the locking locking collar collar is re-is re-tightenedtightened 5.
5. Connect Connect up up cellcell a.
a. Connect the Connect the nozzle at the nozzle at the base of base of the cell the cell to the to the de-aired water supply, de-aired water supply, and close and close thethe inlet cock,
inlet cock, b.
b. Connect each Connect each piezometer point that piezometer point that is to is to be used be used to a to a manometer tube manometer tube and close and close withwith a pinchcock close to the
a pinchcock close to the cell,cell, c.
c. Connect thConnect the top oue top outlet of the tlet of the cell to the cell to the vacuum, fitvacuum, fitted with a ted with a water trapwater trap, using r, using rigidigid plastic or thick-walled rubber tubing
DEPARTMENT:
DEPARTMENT: INFRASTRUCTURINFRASTRUCTURE E ANDAND GEOMATIC ENGINEERING GEOMATIC ENGINEERING EDITION: EDITION: REVIEW NO.: REVIEW NO.: TEST TITLE:
TEST TITLE: CONSTANT HEADCONSTANT HEAD PERMEABILITY TEST PERMEABILITY TEST EFFECTIVE EFFECTIVE DATE: DATE: 3/01/12 3/01/12 AMENDMENT AMENDMENT DATE: DATE: 3/01/12 3/01/12 6.
6. Saturate Saturate and and de-air de-air samplesample 7.
7. Connect Connect up up for for testtest 8.
8. Run Run testtest a.
a. Turn on Turn on the supply of the supply of de-aired water to de-aired water to the constant head device, the constant head device, which be at which be at a lowa low level initially,
level initially, b.
b. Open waOpen water supply ter supply valve that valve that connect it connect it to the cell, to the cell, and the and the base outlebase outlet cockt cock c.
c. Allow water to Allow water to flow through the flow through the sample until the sample until the conditions appear to conditions appear to be steady be steady and theand the water levels in the manometer tubes remain stationary
water levels in the manometer tubes remain stationary d.
d. Adjust valve on Adjust valve on the supply the supply line to line to the constant head the constant head device so device so that there that there is ais a continuou
continuous small overflow; if s small overflow; if this is excessive, the this is excessive, the de-aired watede-aired water will be r will be wasted.wasted. e.
e. To start a test rTo start a test run, empty the un, empty the measuring measuring cylinder and cylinder and start the timer start the timer at the instant that the instant thee measuring cylinder is placed under the outlet overflow.
measuring cylinder is placed under the outlet overflow. f.
f. Record Record the the clock timclock time at e at which which the fthe first rirst run is un is started.started. g.
g. Read the Read the levels of levels of the water the water in the in the manometer tubes manometer tubes (h(h11, h, h22, etc.) and measure the, etc.) and measure the
water temperature (T
water temperature (T
C) in the outlet reservoir.C) in the outlet reservoir. h.h. When the When the level in level in the cylinder reaches the cylinder reaches a predetermined a predetermined mark (such mark (such as 50ml as 50ml or 200ml)or 200ml) stop the clock, record the elapsed time to the nearest half second,
stop the clock, record the elapsed time to the nearest half second, 9.
9. Repeat Repeat testtest a.
a. Empty the Empty the cylinder, and make cylinder, and make four to four to six repeat runs six repeat runs at about at about 5 minutes 5 minutes intervalsintervals.. 10.
10. Dismantle ceDismantle cellll 11.
11. Calculate reCalculate resultssults 12. Report
12. Report
Figure 2: General arrangement for constant head permeability test (downward flow) Figure 2: General arrangement for constant head permeability test (downward flow)
(Courtesy of ELE International, 2007) (Courtesy of ELE International, 2007)
DEPARTMENT:
DEPARTMENT: INFRASTRUCTURINFRASTRUCTURE E ANDAND GEOMATIC ENGINEERING GEOMATIC ENGINEERING EDITION: EDITION: REVIEW NO.: REVIEW NO.: TEST TITLE:
TEST TITLE: CONSTANT HEADCONSTANT HEAD PERMEABILITY TEST PERMEABILITY TEST EFFECTIVE EFFECTIVE DATE: DATE: 3/01/12 3/01/12 AMENDMENT AMENDMENT DATE: DATE: 3/01/12 3/01/12 6.0 RESULTS AND
6.0 RESULTS AND CALCULATIOCALCULATIONSNS Constant Head Permeability test Constant Head Permeability test
Location:
Location:
Pantai Punggur
Pantai Punggur
Sample Sample no:no:2
2
Operator: Date: Operator: Date: Soil description:
Soil description:
Light brown sand
Light brown sand
Method of Method of preparation:
preparation:
lightly compacted in 3 layers
lightly compacted in 3 layers
Sample diameter:
Sample diameter:
80
80
mm mm Sample Sample length:length:232
232
mm mm Sample area, A:Sample area, A:
5026
5026
mm mm22 Sample Sample volume:volume:1166
1166
mm mm33Sample dry mass:
Sample dry mass:
1925
1925
g g Sample Sample dry dry density:density:16.19
16.19
kN/m kN/m33S.G. measured/assumed:
S.G. measured/assumed:
2.65
2.65
Voids Voids ratio:ratio:0.8
0.8
Heights
Heights above above datum: datum: inlet inlet mm mm Heights Heights above above datum: datum: outlet outlet mmmm Manometer
Manometer a: a: mm mm Manometer Manometer b: b: mm mm Manometer Manometer c: c: mmmm Head difference a to c,
Head difference a to c,
H: H: mmmm Distance Distance difference, difference, L: L: mmmm Flow upwards/downwardsFlow upwards/downwards Hydraulic gradients (Hydraulic gradients (
H/L) H/L) mmmm Temperature: Temperature: Reading: Reading: Time from Time from start start min. min. Time interval, Time interval, tt min. min. Measured Measured flow, Q flow, Q ml ml Rate of flow, q Rate of flow, q = Q/t = Q/t ml/min ml/min t t 1 1tt ==time from start time from start
2
2
2
2
4
4
2
2
6
6
2
2
8
8
2
2
10
2
10
2
15
5
15
5
20
5
20
5
25
5
25
5
30
5
30
5
35
5
35
5
45
10
45
10
DEPARTMENT:
DEPARTMENT: INFRASTRUCTURINFRASTRUCTURE E ANDAND GEOMATIC ENGINEERING GEOMATIC ENGINEERING EDITION: EDITION: REVIEW NO.: REVIEW NO.: TEST TITLE:
TEST TITLE: CONSTANT HEADCONSTANT HEAD PERMEABILITY TEST PERMEABILITY TEST EFFECTIVE EFFECTIVE DATE: DATE: 3/01/12 3/01/12 AMENDMENT AMENDMENT DATE: DATE: 3/01/12 3/01/12 a)
a) Plot Plot the the graph graph of of q q versus 1/versus 1/
t and determine the value of q at 1/t and determine the value of q at 1/
t is equal to zero.t is equal to zero. b)b) Use the Use the q from q from the graph the graph to calculate to calculate the permeability.the permeability.
Calculations: Calculations: Permeability, k = Permeability, k =
q
q
A
Ai
i 6
60
0
= _________________ (m/s) = _________________ (m/s) 7.0 QUESTIONS 7.0 QUESTIONS 1.1. Determine the Determine the coefficiecoefficient nt of of permeability for permeability for the the given given soil sample.soil sample.
2.
