Research Methodolgy & Intellectual Property Rights Series 1
Consolidation Test by Parez Abdullah Mohammed
1. 1
University of Raparin
Presidency of University of Raparin
Civil Engineering Department
Third Stage
Soil Mechanics – Practical
Consolidation Test
Student Name: Parez Abdullah Mohammed
Lab ReportNo.: #9
Group: B
Date of Test: 27/1/2019
Date of Report Submission: 16/2/2019
2018-2019
3. 3
Introduction:
This report documents preparing and operating the experiment of consolidation test in soil which
is done in the civil engineering department in Koya University.
Consolidation is the process of time-dependent settlement of saturated clayey soil when subjected
to au increased loading. In this chapter, the procedure of a one-dimensional laboratory consolidation test
will be described, aud the methods of calculation to obtain the void ratio pressure curve (e vs.logp), the
preconsolidation pressure (Pc), aud the coefficient of consoli-dation (cv) will be outlined.
Standard Reference:
ASTM – D2435
Apparatus:
1. Consolidation test unit
2. Specimen trimming device
3. Wire saw
4. Balauce sensitive to 0.01 g
. 5. Stopwatch
6. Moisture cau
7. Oven
4. 4
Procedure:
1. I. Prepare a soil specimen for the test. The specimen is prepared by trimming an undis-turbed natural
sample obtainedinshelbytubes.The shelbytube sample shouldbe aboutV.in.toY2in.(6.35 mm to 12.7
mm) larger in diameter than the specimen dia-
2. meter to be prepared for the test.
3. 2. Collect some excess soil that has been trimmed in a moisture can for moisture
4. content determination.
5. 3. . Collect some of the excess soil trimmed in Step I for determination of the specific
6. gravity of soil solids, Gs'
7. 4. Determine the mass of the consolidation ring (WI) in grams.
8. 5. Place the soil specimen in the consolidation ring. Use the wire saw to trim the speci-
9. menflushwiththe topand bottomof the consolidationring.Recordthe size of the specimen,i.e.,height
[H'(i)] and diameter (D).
10. 6. Determine the mass of the consolidation ring and the specimen (W2) in grams.
11. 7. Saturated the lower porous stone on the base of the consolidometer.
12. 8. Place the soil specimen in the ring over the lower porous stone.
13. 9. Place the upper porous stone on the specimen in the ring.
14. 10. Attach the top ring to the base of the consolidometer.
15. 11. Add waterto the consolidometertosubmerge the soil andkeepit saturated.Inthe case of the fixed
ring consolidometer, the outside ring (which is attached to the top
16. of the base) andthe standpipe connectionattachedtothe base shouldbe keptfullwithwater.Thisneeds
to be done for the entire period of the test.
17. 12. Place the consolidometer in the loading device.
5. 5
18. 13. Attachthe vertical deflectiondialgauge tomeasure the compressionof soil.Itshouldbe fixedinsuch
as way that the dial isat the beginningof its releaserun.The dial gauge shouldbe calibratedtoreadas 1
small division = 0.0001. (0.00254 mm).
19. 14. Applyloadtothe specimensuchthatthe magnitude of pressure,p,onthe specimenisII,ton/W(45.88
kN/m~. Take the vertical deflection dial gauge readings at the
20. following times, t, counted from the time of load application-O min., 0.25 min. 1
21. . min., 2.25 min., 4 min., 6.25 min., 9 min., 12.25 min:, 20.25 min., 25 min., 36 min.,
22. 60 min., 120 min., 240 min., 480 min., and 1440 min. (24 hr.).
23. 15. The next day, add more load to the specimen such that the total magnitude of pres-
24. 'sure on the specimen becomes 1 tOn/ft2 (95.76 kN/m2). Take the vertical·dialgauge reading at similar
time intervals as stated in Step 14. Note: Here we have I1p / p = 1
25. (where tlp = increase in pressure and p = the pressure before the increase).
26. 16. Repeat Step 15 for soil pressure magnitudes of2 tonlft2 (299.52 kN/m2),
7. 7
Calculation
Dry = Ws/V
Ws= dry * V = 1.4 * 12.5 = 17.5 g
Hs= Ws/A Gs w = 17.5/ 6.25*2.7*1 = 1.037 cm = 10.37 mm
Time Load
H of
sample Hv e
0 0 20 9.63 0.92864
0.5 0.085 19.915 9.545 0.920444
1 0.265 19.735 9.365 0.903086
2 0.53 19.47 9.1 0.877531
4 0.942 19.058 8.688 0.837801
10 1.63 18.37 8 0.771456
15 2.518 17.482 7.112 0.685824
25 3.5 16.5 6.13 0.591128
40 4.485 15.515 5.145 0.496143
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.01 0.1 1 10
e
8. 8
Discussion
Basedon the experimental data obtained in the laboratory, dry density and specific gravity values of tropical
peat correlate well. When large loads such as embankments are applied to the surface, cohesive sub soils will
consolidate, such as settle over time, through a combination of the rearrangement of the individual particles and the
squeezing out of water. The amount and rate of settlement is of great importance in construction of such structure
on a curtain soil area. For example, an embankment may settle until a gap exists between an approach and a bridge
abutment. The calculation of settlement involves many factors, including the magnitude of the load, the effect of
the load at the depth at which compressible soils exist, the water table, and characteristics of the soil itself
9. 9
References
1. The book
(Braja M. Das-Soil Mechanics Laboratory Manual-Oxfor University Press (2002))
2. ASTM D2435
3. https://www.scribd.com/document/393432513/Consolidation-Test-Discussion-and-
Conclusion
