Determination of strength and stress-strain relationships of a cylindrical specimen of reconstituted specimen using Consolidated Drained (CD) Triaxial Test. 1. A series of drained triaxial tests under four different initial states were conducted on Yamuna River sand. The results consist of simple stress-strain relation, change in volume behaviour were plotted. 2. Basic stress-strain relation with volume behaviour was presented in plot. The results for densely prepared sand samples show an expected behaviour. There is a significant difference in peak and residual deviatoric stress (q) as can be depicted form the plot. 3. With increase in confining stress, load carrying capacity of specimen increases. 4. Saturation value ‘B’ must be acquired to be more than 0.95 before starting the isotropic consolidation phase in CD test. 5. CD tests are performed at much slower strain rate as compared to CU tests for the same soil. The strain rate for CD test can be chosen approx. 8-10 times lower than the CU test. 6. It is important to have no pore water pressure generation throughout the shearing phase of CD test or in other words strain rate must be so small that pore water pressure must get dissipated quickly when specimen is subjected to compression loading in CD test. 7. In CD test, volumetric strain versus axial strain relationship shows contractive response for NC soils and dilative response for OC soils. (NC = Normally consolidated, OC = Over consolidated) References: 1. IS: 2720 (Part 11):1993- Determination of the shear strength parameters of a specimen tested in unconsolidated undrained triaxial compression without the measurement of pore water pressure (first revision). Reaffirmed- Dec 2016. 2. IS: 2720 (Part 12):1981- Determination of Shear Strength parameters of Soil from consolidated undrained triaxial compression test with measurement of pore water pressure (first revision). Reaffirmed- Dec 2016. 3. ASTM D7181-11. Method for Consolidated Drained Triaxial Compression Test for Soils; ASTM: West Conshohocken, PA, USA, 2011.

1. 1
Department of Civil Engineering, IIT Delhi
Submitted By:
Abhinav Kumar
Soil Engineering Lab
REPORT TITLE (12)
Consolidated Drained (CD)
Triaxial Test
Disclaimer: This presentation is for educational purposes only. Opinions or points of
view expressed in this presentation represent the view of the presenter, and does not
necessarily represent the official position or policies of IIT Delhi. Nothing in this
presentation constitutes legal advice. The individuals appearing in this presentation, if
any, are depicted for illustrative purposes only and are presumed innocent until proven
guilty in a court of law. Under no circumstance shall we have any liability to you for any
loss or damage of any kind incurred as a result of the use of the data or reliance on any
information provided. Your use of the document and your reliance on any information is
solely at your own risk

2. 2
Objective: Determination of strength and stress-strain relationships of a cylindrical specimen of
reconstituted specimen using Consolidated Drained (CD) Triaxial Test.
Apparatus:
1. Triaxial Shear Test Apparatus, Triaxial Shear Test Setup, Open ended cylindrical section, Weighing
balance, 3.8 cm (1.5 inch) internal diameter 7.6 cm (3 inches) long sample tubes.
2. Rubber membrane, membrane stretcher, porous stone.
Triaxial Apparatus
Triaxial Test Assembly
O- Rings
Porous Stone Mould

3. 3
Testing methods and Procedures:
1. The shear strength of a saturated soil (Yamuna Sand) in triaxial compression depends on the stresses
applied, time of consolidation, strain rate, and the stress history experienced by the soil. In this test, the
shear characteristics are measured under drained conditions and are applicable to field conditions where
soils have been fully consolidated under the existing normal stresses and the normal stress changes under
drained conditions similar to those In the test method. The shear strength determined from the test is
commonly used in embankment stability analysis, earth pressure calculations, and foundation design.
The following image shows three phases of
CD triaxial testing; sampling stage, Isotropic
loading stage (application of confining
pressure for consolidation under isotropic
conditions), shearing stage (application of
deviator stress, σd). Three parameters are
shown at each phase of CD triaxial testing in
the given diagram; total stress, pore
pressure and effective stresses. ur is the
residual pore water pressure entrapped
inside the soil specimen after its collection
from soil site using UDS (Undisturbed
sampling) tube. The residual pore water
pressure (ur) entrapped inside the soil mass
gets dissipated when drainage valves are
kept open for saturation of soil specimen
(CO2 saturation, water saturation and
application of back pressure). After saturation stage, pore pressure is not allowed to generate in next two
stages of the test by keeping the drainage valves open during isotropic consolidation & shearing stages.
Thus, diagram shows pore pressure values to be zero in second & third stage of CD test. Shear
deformation stage in CD test must be conducted under low strain rate to avoid pore pressure generation
when specimen is subjected to compression loading.
.2. Specimen Preparation
Remolded Specimen(R):
For the desired water content and the dry density, calculate the
weight of the dry soil Ws required for preparing a specimen of 38 mm
diameter and 76 mm long.
Required quantity of water Ww was added to this soil.
Ww = Ws x W/100 gm
The soil was mixed thoroughly with water.

4. 4
The soil was placed in a constant volume mould, having an internal height of 76 mm and internal diameter
of 38 mm. The mould was filled and compacted maintaining the saturation.
The height, weight and diameter of the specimen was recorded.
Testing procedure:
The saturated porous stone disc of diameter same as the sample was placed on top of the pedestal of
triaxial testing machine and the circular filter paper of same size is placed over the disc. Specimen was
placed on top of the filter paper. The filter paper with porous stone was placed on top of the specimen to
allow two-way drainage.
The latex membrane was stretched in the membrane stretcher and placed on the soil specimen. O-rings
were placed at top and bottom of platens of the soil specimen to prevent the cell water entering into the
specimen.
The triaxial cell is placed over the base and tightened with the screws. The cell was then filled with water
and a small confining pressure of about 10 kPa is applied to hold the specimen in place.

5. 5
The soil specimen needs to be completely saturated before isotropic
consolidation phase.
Isotropic consolidation stage was started by applying confining pressure. During
the Consolidation stage, drainage valve was kept open and the volume change
was measured until no change in volume was observed (when primary
consolidation is over).
In the Consolidated Drained (CD) triaxial test, drainage valves are kept open
during shearing stage and volume change is measured throughout the test using
the volume change transducer.
The loading machine is set in motion at an appropriate strain rate based on
the soil type (much lower strain rate than CU testing for same soil). Data
acquisition system (DAQ) is attached with the computer. load cell & transducers
of triaxial system, which records the data with the help of triaxial CD software.
The experiment is stopped at around 15% strain.
Calculations and Results:
GROUP - 1
Yamuna sand
Water sedimentation
S.No. Length of assembly
Length of
assembly +
soil
specimen
1 62.1 137.76
2 61.93 138.73
3 62.25 138.69
Average 62.0933 138.3933
Initial length of
specimen (mm)
76.3 Initial diameter of sample (mm) 34.585
Intial Volume of
sample (cc)
71.67868 Initial area of
sample (mm2
)
939.4322
σc = 100 kPa
Strain rate = 0.19 mm/min
S. No.
Measured
Diameter
Thickness of
Rubber
Membrane
1 35.94 0.69
2 35.62 0.67
3 36.29 0.7
4 35.93 0.66
Average 35.945 0.680
Suction creation for stabilizing
cohesionless soil sample

6. 6
Elapsed
Time
(sec)
√t
√min
Burette
Reading
(cc)
ΔV
(ml)
0 0.000 17.3 0
5 0.289 15.1 -2.2
10 0.408 15.1 -2.2
15 0.500 15.1 -2.2
20 0.577 15 -2.3
25 0.645 15 -2.3
30 0.707 15 -2.3
35 0.764 15 -2.3
40 0.816 15 -2.3
45 0.866 15 -2.3
50 0.913 15 -2.3
55 0.957 15 -2.3
60 1.000 15 -2.3
65 1.041 15 -2.3
70 1.080 15 -2.3
75 1.118 15 -2.3
80 1.155 15 -2.3
85 1.190 15 -2.3
90 1.225 15 -2.3
95 1.258 15 -2.3
100 1.291 15 -2.3
105 1.323 15 -2.3
110 1.354 15 -2.3
115 1.384 15 -2.3
120 1.414 15 -2.3
125 1.443 15 -2.3
130 1.472 15 -2.3
135 1.500 15 -2.3
140 1.528 15 -2.3
145 1.555 15 -2.3
150 1.581 15 -2.3
155 1.607 15 -2.3
160 1.633 15 -2.3
165 1.658 15 -2.3
170 1.683 15 -2.3
175 1.708 15 -2.3
180 1.732 15 -2.3
185 1.756 15 -2.3
kgf Divisions
0 0
20 114
40 230
60 345
80 461
100 578
120 694
140 812
160 930
180 1047
200 1164
After Consolidation
εv 0.032
L (mm) 75.484
D (mm) 34.215
V (mm3
) 69403.190
A (mm2
) 919.444
y = 0.1716x + 0.5402
0
50
100
150
200
250
0 200 400 600 800 1000 1200 1400
kgf
Divisions
Calibration Chart ( Proving Ring No- 16076)
-2.5
-2
-1.5
-1
-0.5
0
0.000 0.500 1.000 1.500 2.000
ΔV
(ml)
√t
(√min)
ΔV vs √t Plot

7. 7
Data Table
σc = 100 KPa
Burette
Reading
Vertical
Displ.
Reading
Vertical
Strain in
%
Volume
Change
(cc)
Volumetric
Strain
(%)
Corrected
Area
(cm2)
Proving
Ring
Dial
Reading
Change in
Proving
Ring
Reading
Load on
Proving
Ring (N)
Deviatoric
Load
(N)
Deviator
Stress
(σ1 - σ3)
(KPa)
15.00 0 0 0.00 0.000 9.194 24.00 0 0.000 0.000 0.000
15.00 25 0.331 0.00 0.000 9.225 24.14 14 23.568 23.568 25.548
15.00 50 0.662 0.00 0.000 9.256 24.20 6 10.100 33.668 36.375
15.00 75 0.994 0.00 0.000 9.287 24.19 -1 -1.683 31.985 34.441
15.00 100 1.325 0.00 0.000 9.318 24.18 -1 -1.683 30.301 32.519
14.95 125 1.656 -0.05 -0.072 9.343 24.20 2 3.367 33.668 36.037
14.95 150 1.987 -0.05 -0.072 9.374 24.25 5 8.417 42.085 44.895
14.90 175 2.318 -0.10 -0.144 9.399 24.85 60 101.004 143.089 152.237
14.80 200 2.650 -0.20 -0.288 9.417 25.34 49 82.486 225.575 239.529
14.70 225 2.981 -0.30 -0.432 9.436 25.73 39 65.652 291.228 308.636
14.65 250 3.312 -0.35 -0.504 9.461 26.07 34 57.235 348.463 368.299
14.65 275 3.643 -0.35 -0.504 9.494 26.34 27 45.452 393.915 414.911
14.80 300 3.974 -0.20 -0.288 9.547 26.58 24 40.402 434.316 454.906
14.90 325 4.306 -0.10 -0.144 9.594 26.77 19 31.985 466.301 486.020
15.00 350 4.637 0.00 0.000 9.641 26.92 15 25.251 491.552 509.830
15.10 375 4.968 0.10 0.144 9.689 27.06 14 23.568 515.119 531.652
15.30 400 5.299 0.30 0.432 9.751 27.15 9 15.151 530.270 543.817
15.40 425 5.630 0.40 0.576 9.799 27.24 9 15.151 545.420 556.599
15.60 450 5.962 0.60 0.865 9.862 27.31 7 11.784 557.204 565.010
15.80 475 6.293 0.80 1.153 9.925 27.39 8 13.467 570.671 574.985
15.95 500 6.624 0.95 1.369 9.981 27.45 6 10.100 580.772 581.851
16.20 525 6.955 1.20 1.729 10.053 27.48 3 5.050 585.822 582.758
16.30 550 7.286 1.30 1.873 10.103 27.50 2 3.367 589.189 583.195
16.50 575 7.618 1.50 2.161 10.168 27.50 0 0.000 589.189 579.472
16.70 600 7.949 1.70 2.449 10.233 27.50 0 0.000 589.189 575.771
16.90 625 8.280 1.90 2.738 10.299 27.50 0 0.000 589.189 572.090
17.10 650 8.611 2.10 3.026 10.365 27.50 0 0.000 589.189 568.430
17.20 675 8.942 2.20 3.170 10.417 27.50 0 0.000 589.189 565.579
17.45 700 9.274 2.45 3.530 10.492 27.50 0 0.000 589.189 561.561
17.60 725 9.605 2.60 3.746 10.552 27.50 0 0.000 589.189 558.345
17.80 750 9.936 2.80 4.034 10.621 27.50 0 0.000 589.189 554.759
18.00 775 10.267 3.00 4.323 10.689 27.50 0 0.000 589.189 551.192
18.15 800 10.598 3.15 4.539 10.751 27.50 0 0.000 589.189 548.022
18.30 825 10.929 3.30 4.755 10.813 27.50 0 0.000 589.189 544.865
18.40 850 11.261 3.40 4.899 10.869 27.50 0 0.000 589.189 542.094
18.60 875 11.592 3.60 5.187 10.939 27.50 0 0.000 589.189 538.591
18.70 900 11.923 3.70 5.331 10.996 27.50 0 0.000 589.189 535.839

8. 8
18.80 925 12.254 3.80 5.475 11.052 27.45 -5 -8.417 580.772 525.479
18.95 950 12.585 3.95 5.691 11.117 27.43 -2 -3.367 577.405 519.397
19.00 975 12.917 4.00 5.763 11.167 27.40 -3 -5.050 572.355 512.554
19.20 1000 13.248 4.20 6.052 11.240 27.35 -5 -8.417 563.938 501.729
Max.
Value 583.195
0
100
200
300
400
500
600
700
0 2 4 6 8 10 12 14
Deviatoric
stress
(KPa)
Strain (%)
Deviatoric stress vs strain
Deviatoric stress vs strain

9. 9
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
5.25
5.50
5.75
6.00
6.25
6.50
0 2 4 6 8 10 12 14
Volumetric
Strain
(%)
Axial Strain (%)
Volumetric Strain Vs Axial Strain
100 kPa Poly. (100 kPa)

10. 10
Confining
pr (KPa) 100
Confining
pr (KPa) 200
Confining
pr (KPa) 400
Confining
pr (KPa) 300
G-1 G-2 G-3 G-4
strain (%)
deviatoric
stress
(Kpa) strain (%)
deviatoric
stress (Kpa) strain (%)
deviatoric
stress
(Kpa) strain (%)
deviatoric
stress
(Kpa)
0 0 0 0 0 0 0 0
0.331196 44.8949 0.35062 60.0618662 0.3193205 203.7206 0.3155052 177.082
0.662393 152.237 0.70124 192.236767 0.6386411 363.8305 0.6310104 347.395
0.993589 239.529 1.05186 331.245927 0.9579616 500.4174 0.9465156 488.365
1.324786 308.636 1.40248 451.654607 1.2772822 627.7092 1.2620207 605.356
1.655982 368.299 1.7531 505.514146 1.5966027 740.2012 1.5775259 697.266
1.987179 414.911 2.10372 599.882168 1.9159233 835.2454 1.8930311 777.416
2.318375 454.906 2.45434 678.713945 2.2352438 918.5539 2.2085363 846.039
2.649571 486.02 2.80496 745.282559 2.5545644 1015.131 2.5240415 903.922
2.980768 509.83 3.15558 804.650489 2.8738849 1064.186 2.8395467 950.06
3.311964 531.652 3.5062 849.251951 3.1932054 1112.898 3.1550519 986.255
3.643161 543.817 3.85682 934.899497 3.512526 1158.526 3.4705571 1015.8
3.974357 556.599 4.20744 970.691371 3.8318465 1203.827 3.7860622 1044.76
4.305554 565.01 4.55806 1002.97453 4.1511671 1240.641 4.1015674 1067.93
4.63675 574.985 4.90868 1036.63335 4.4704876 1269.046 4.4170726 1086.5
4.967947 581.851 5.2593 1053.95793 4.7898082 1294.531 4.7325778 1104.88
5.299143 582.758 5.60992 1067.18217 5.1091287 1314.429 5.048083 1120.17
5.630339 583.195 5.96054 1076.59401 5.4284493 1339.533 5.3635882 1133.87
5.961536 579.472 6.31116 1088.03794 5.7477698 1359.087 5.6790934 1144.55
6.292732 575.771 6.66178 1096.54721 6.0670904 1373.145 5.9945986 1155.83
6.623929 572.09 7.0124 1099.6087 6.3864109 1384.419 6.3101037 1166.82
6.955125 568.43 7.36302 1105.75796 6.7057314 1392.936 6.6256089 1174.3
7.286322 565.579 7.71364 1107.34131 7.025052 1398.723 6.9411141 1178.97
7.617518 561.561 8.06426 1109.04675 7.3443725 1404.438 7.2566193 1183.46
7.948714 558.345 8.41488 1106.33536 7.6636931 1404.838 7.5721245 1187.87
8.279911 554.759 8.7655 1106.06753 7.9830136 1407.814 7.8876297 1190.82
8.611107 551.192 9.11612 1103.22825 8.3023342 1408.132 8.2031349 1192.32
8.942304 548.022 9.46674 1098.15751 8.6216547 1408.415 8.51864 1191.09
9.2735 544.865 9.81736 1092.65619 8.9409753 1403.491 8.8341452 1191.14
9.604697 542.094 10.168 1088.77909 9.2602958 1398.568 9.1496504 1187.07
9.935893 538.591 10.5186 1077.07394 9.5796163 1393.645 9.4651556 1183.01
10.26709 535.839 10.8692 1075.22814 9.8989369 1388.722 9.7806608 1178.94
10.59829 525.479 11.2198 1070.93082 10.218257 1378.702 10.096166 1174.87
10.92948 519.397 11.5705 1062.92649 10.537578 1371.257 10.411671 1169.47
11.26068 512.554 11.9211 1051.56427 10.856899 1361.3 10.727176 1164.08
11.59188 501.729 12.2717 1038.08152 11.042682 1158.7

11. 11
12.6223 1018.79821 11.358187 1150.77
12.9729 996.738855 11.673692 1145.43
13.3236 971.532051 11.989197 1138.86
13.6742 930.180756 12.304702 1134.78
14.0248 905.672337 12.620207 1129.47
max
value 583.195 1109.04675 1408.415 1192.32
0
200
400
600
800
1000
1200
1400
1600
0 2 4 6 8 10 12 14 16
Deviatoric
Stress
(kPa)
Axial Strain %
Deviatoric Stress Vs Axial Strain
100 KPa 200 KPa 300 KPa 400 KPa

12. 12
Confining
press.
(kPa)
Max.
Deviatoric
stress (kPa)
s (kPa) t (kPa)
100 583.195 391.597 291.597
200 1109.05 754.523 554.523
300 1192.32 896.161 596.160
400 1408.41 1104.21 704.207
Post Shearing Water Content
Determination
container no G1
wt of empty
container (g) 96.11
wt of container with
moist soil (g) 250.97
wt of container with
oven dried soil (g) 219.19
wt of water (Ww)
(g) 31.78
wt of dry soil (Ws)
(g) 123.08
water content (w) 0.258206
Water content (%) 25.8206
d 35.295°
Cd
(kPa) 100.631
t = 0.5778s + 82.133
0
100
200
300
400
500
600
700
800
0 200 400 600 800 1000 1200
t
(KPa)
s (KPa)
s v/s t curve
Modified Failure Envelope

13. 13
Result:
1. For the given soil i.e., Yamuna Sand the Undrained angle of shearing resistance (ød)= 35.295°
2. The undrained cohesion intercept (Cd) =100.631 kPa
Individual Discussion:
1. A series of drained triaxial tests under four different initial states were conducted on Yamuna
River sand. The results consist of simple stress-strain relation, change in volume behaviour were
plotted.
2. Basic stress-strain relation with volume behaviour was presented in plot. The results for densely
prepared sand samples show an expected behaviour. There is a significant difference in peak and
residual deviatoric stress (q) as can be depicted form the plot.
3. With increase in confining stress, load carrying capacity of specimen increases.
4. Saturation value ‘B’ must be acquired to be more than 0.95 before starting the isotropic
consolidation phase in CD test.
5. CD tests are performed at much slower strain rate as compared to CU tests for the same soil. The
strain rate for CD test can be chosen approx. 8-10 times lower than the CU test.
6. It is important to have no pore water pressure generation throughout the shearing phase of CD
test or in other words strain rate must be so small that pore water pressure must get dissipated
quickly when specimen is subjected to compression loading in CD test.
7. In CD test, volumetric strain versus axial strain relationship shows contractive response for NC
soils and dilative response for OC soils. (NC = Normally consolidated, OC = Over consolidated)
References:
1. IS: 2720 (Part 11):1993- Determination of the shear strength parameters of a specimen tested in
unconsolidated undrained triaxial compression without the measurement of pore water pressure
(first revision). Reaffirmed- Dec 2016.
2. IS: 2720 (Part 12):1981- Determination of Shear Strength parameters of Soil from consolidated
undrained triaxial compression test with measurement of pore water pressure (first revision).
Reaffirmed- Dec 2016.
3. ASTM D7181-11. Method for Consolidated Drained Triaxial Compression Test for Soils; ASTM:
West Conshohocken, PA, USA, 2011.