EXAMPLE TECHNICAL MEMO REPORT
Department of Civil Engineering
Attached is an example technical memo report for you to use as a guideline to use for
memo-style reports for lab courses CE207L, CE330L, CE354L and CE415L. The memo
heading, body, summary of results and the appendix should be included in each memostyle lab report you write. While you should strive to use similar formatting and layout,
you are urged to use your own creativity to develop an individual, yet professional style.
Keep it simple and concise.
For these lab memos, you should consider your audience to be technically inclined people
who read a lot of highly technical material. Use passive, third-person, past-tense for most
cases. If there is a need to communicate via memo on a topic outside of the actual lab
report setting, you may use less formal, first-person language and form.
Some other tips:
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Don’t use script or other fonts since they may make the document harder to read.
Serif fonts (fonts having pointed features like this Times New Roman font) at 12
point pitch are preferred.
Avoid non-serif fonts, like Arial or Microsoft Sans Serif. They are typically
harder to read when the text is densely packed, such as in a single-spaced
paragraph. Non-serif fonts usually work well for spreadsheet or graph text that is
less densely packed.
Keep sentences short, but not choppy. Use clear, concise language and keep your
thoughts organized.
Leave a blank line between paragraphs.
Include references in an endnote (at the end of the memo body). Only include
references that you actually refer to in the memo body. The reference citation style
should follow the ASCE standard entitled “Authors' Guide to Journals and Practice
Periodicals”. For an explanation and several examples see the information at
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Verify all personal names and titles.
Use plenty of white-space to separate tables and charts (graphs).
Label tables and figures for quick reference in the memo body.
Make tables and charts large enough so the reader can easily see the content.
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PLEASE PROOFREAD! Spelling and grammar errors will reduce your score in
the report evaluation phase.
9/15/2006
SIUE Department of Civil Engineering
TECHNICAL MEMORANDUM
To:
Rocky Stone
From:
Clay E. Sample, Group 4 - Section 1
Date:
9/15/2006
Re:
Report 2, covering:
Lab 6- Permeability Tests, 8/31/2006, Group leader: Sandy Darcy
Lab 7- Compaction, 9/7/2006, Group leader: Stan Proctor
Lab 8- Unconfined Compression, 9/14/2006, Group Leader: Clay Sample
Introduction
Group 4 (members include Clay Sample, Sandy Darcy and Stan Proctor) recently completed the
three laboratory experiments referenced above. The general procedures, observations and
conclusions are summarized below. The summary of results, test data and analysis with sample
calculations are attached.
Permeability Tests
The teaching assistant prepared the soil sample for the permeability tests before the class period by
mixing soils consisting of a range of grain sizes. According to the procedures in the text (Liu
1990), the soil specimen should be evacuated under vacuum to remove air and then slowly
saturated from the bottom up. This was not done because a source of vacuum was not available at
the time. Water was allowed to run through the sample in the permeameter for several minutes
before proceeding with the next two trials. An AutoCAD drawing (Figure 1) illustrating the
equipment setup is attached to this report.
The constant-head test was performed as described in Chapter 16 of the text. The test was
conducted five times because the results of the first two trials seemed very erratic so the data was
deemed unusable. We determined that the soil for the first two trials was probably not saturated.
Data collected for the third through fifth trials were more consistent and those results seemed
reasonable.
The falling-head permeability tests were generally performed as described in Chapter 17 of the text
with the same soil sample used for the constant-head tests. According to the text, this test should be
run three times with three different samples, each compacted to a different density. This was not
done, again because of the lack of time available in the lab period. Instead, the test was run three
times, but with the same soil sample. Test data are tabulated in Table 1 in the appendix. The
results for the falling-head tests were slightly higher than the constant-head tests (averages: 2.37 x
10-4 cm/s vs. 2.20 x 10-4 cm/s). This variation could be a result of minor differences in the way the
tests were performed, but it is more likely that the saturation of the soil sample was continuing to
increase. Note that the void ratio for the permeability test was based on the assumption that the soil
sample was 100% saturated. Since the air was not completely evacuated from the soil sample, it is
likely that this assumption was not correct and the accuracy of the void ratio calculation could be
questioned. However, since the results of the two tests were reasonably consistent, the results are
probably representative of the actual permeability.
9/15/2006
Memo: Rocky Stone / Report 2
Page 2 of 2
Standard Proctor Maximum Dry Density Tests
The Standard Proctor maximum dry density (compaction) tests were performed in general
accordance with Chapter 11 in the text (Liu 1990) which essentially follows ASTM D698-00a. For
the calculations, the specific gravity of the soil was assumed to be 2.73 as determined in a previous
lab. Five compaction trial specimens exhibited a sufficient range of moisture content to establish a
reasonable moisture-density curve. To determine the moisture contents for each specimen, the
average was obtained from soil collected from two areas of the compact soil in the mold. Test data
are tabulated in Table 2 and the corresponding maximum dry density vs. moisture content results
are plotted in Figure 1 in the appendix. The results seemed reasonable and the compaction curve
fell to the left of (below) the zero-air voids curve as expected. The Standard Proctor maximum dry
density was computed to be 99.26 lb/ft3 at the optimum moisture content of 24.2%.
Unconfined Compressive Strength
The compacted soil sample for the Unconfined Compressive Strength lab was prepared before class
by the TAs. Testing was performed in general accordance with the procedure described in the text
(Liu 1990) which generally follows ASTM D2166-00 (ASTM 2003). According to the
specifications, the test specimen’s length-to-diameter ratio (L/D) should be between 2.0 and 2.5.
The specimen we tested had a length of 5.52 inches and a diameter of 2.79 inches for an L/D ratio
of 1.98. Although the L/D ratio was slightly less than 2.0 we did not apply a correction factor since
L/D was only one percent less than the minimum ratio required by the test standard. Force and
deflection data were measured with data acquisition hardware consisting of a linear displacement
transducer and a load cell that were connected to a computer workstation with GENTEST software
operating to collect the data. Test data is tabulated in Table 3 and the corresponding unit stress vs.
strain results are plotted in Figure 2 in the appendix. The sample was loaded to failure at a
maximum load of 193 pounds. The approximate unconfined compressive strength and cohesion
were 3910 and 1950 pounds per square foot, respectively. The rupture failure pattern was not
defined well enough to determine the slope angle of the shearing face. The test ran smoothly,
however, and the results seemed reasonable.
Conclusion
In conclusion, the three experiments covered by this memo included the Falling- and Constant-head
Permeability tests, Standard Proctor Maximum Dry Density test and the Unconfined Compressive
Strength test. Each of the samples was prepared before the lab by the TAs. A summary of results
for each test is attached. Because each of the soil samples used was based on a composite of soil
types and did not necessarily have the same density or plasticity characteristics, the results from
each of the tests can not be reliably correlated in any way. However, since the goal was to learn
how the tests are done and how to analyze the test data, there is no need to look for a correlation
from one test to the other.
Please contact us if you have any questions or comments.
References
ASTM. (2003). Annual Book of ASTM Standards, Volume 04.08 Soil and Rock (I), West
Conshohocken, Pennsylvania.
Liu, Cheng, Evett, Jack B. (1990). Soil Properties Testing, Measurement and Evaluation.
PrenticeHall, Englewood Cliffs, New Jersey.
9/15/2006
Memo: Rocky Stone / Report 2
Page 2 of 2
SUMMARY OF RESULTS
CE354L Group 4 Report 2
9/15/2006
Test
Results
Falling-head Permeability
Soil description ................................ sandy clay (mixed in the lab)
Mass of soil (moist) ............................................................ 7000 g
Permeability..........................................................2.37 x 10-4 cm/s
Constant-head Permeability
Soil description ................................ sandy clay (mixed in the lab)
Mass of soil (moist) ............................................................ 7000 g
Permeability..........................................................2.20 x 10-4 cm/s
Standard Proctor Maximum Dry Density
Soil description ................................................................silty clay
Maximum dry density.................................................99.26 lbs/ft3
Optimum moisture content .................................................. 24.2%
Unconfined Compressive Strength
Soil description ...........................silty clay (compacted specimen)
Specimen height ............................................................. 5.52 inch
Specimen diameter ......................................................... 2.79 inch
Compressive strength ..................................................3910 lbs/ft2
Cohesion .....................................................................1950 lbs/ft2
Table 1. Unconfined Compressive Strength Data
CE354L Group 4
Date of Test: 9/15/2006
Clay E. Sample
Initial sample
height, h0
Initial sample
diameter, d0
Initial cross-sectional area, A0
5.52
inch
2.79
inch
ft2
0.0425
Deformation
Load
Unit Strain
Area
(inch)
0.000
0.040
0.080
0.120
0.160
0.200
0.240
0.280
0.320
0.360
0.400
0.440
0.480
0.520
0.560
0.600
0.640
0.680
0.720
0.760
0.800
0.840
0.880
(lbs)
1.0
7.4
15.5
25.2
34.6
46.0
56.2
66.9
73.3
84.3
94.5
104.7
115.3
127.9
143.4
157.2
168.2
181.4
189.4
192.7
189.4
188.1
181.7
(inch/inch)
0
0.007
0.014
0.022
0.029
0.036
0.043
0.051
0.058
0.065
0.072
0.080
0.087
0.094
0.101
0.109
0.116
0.123
0.130
0.138
0.145
0.152
0.159
(ft2)
0.0425
0.0428
0.0431
0.0434
0.0437
0.0441
0.0444
0.0447
0.0451
0.0454
0.0458
0.0461
0.0465
0.0469
0.0472
0.0476
0.0480
0.0484
0.0488
0.0492
0.0497
0.0501
0.0505
Load per
Unit Area
(lbs/ft2)
24
173
360
581
791
1044
1266
1496
1626
1856
2065
2270
2480
2729
3035
3300
3502
3746
3879
3914
3815
3756
3597
Figure 1. Diagram of the Permeability Test Equipment Configuration
Dwg Date: 9/14/2006
Clay E. Sample
(insert drawing here)
Figure 2. Unit Stress vs. Unit Strain
Unconfined Compressive Strength Test
Test Date: 9/14/2006
Clay E. Sample
5000
4500
Maximum unit stress 3914 lbs/ft
4000
2
Unit Stress (lbs / ft
2
)
3500
3000
2500
2000
1500
1000
500
0
0.00
0.02
0.04
0.06
0.08
0.10
0.12
Unit Strain (inch/inch)
0.14
0.16
0.18
0.20
[NOTE: Effective Fall 2006 semester, Sample Calculations for CE207L, CE330L,
CE354L and CE415L lab reports must be typed (e.g., using either a word processor,
Microsoft Equation, MathCad, or similar program) for a clean, professional
appearance. Also, you must show all relevant units and how they cancel through
the calculation process and result.]
Sample
CE354L
9/15/2006 B Vaughn
1 of 1
Calculations
Unconfined Compressive Strength Test
Soil description: light brown silty clay
Average initial sample height, h0:
h0 =
(5.52 + 5.50 + 5.54) inch
= 5.52 inch
3
Average initial sample diameter, d0:
d0 =
(2.72 + 2.83 + 2.81) inch
= 2.79 inch
3
Initial cross-sectional area, A0:
2
2
A0 = 1 πd 0
4




2
.
79
inch

 = 0.0425 ft 2
=1 π
4  12 inch 


 1 ft 
Compute the axial unit strain,ε, at a given load level (the remaining calculations correspond to the
maximum load level recorded):
Axial load applied, P = 192.7 lbs
Axial deformation, ∆h = 0.760 inch
ε=
∆h 0.760 inch
=
= 0.138
h0
5.52 inch
Compute the corresponding cross-sectional area, A:
A=
A0
0.0425 ft 2
=
= 0.0493 ft 2
1− ε
1 − 0.138
Compute the corresponding unit stress, qu:
qu =
P 192.7 lbs
lbs
=
= 3914 2
2
A 0.0493 ft
ft
Compute the maximum cohesion, cu:
cu =
qu
=
2
3914
2
lbs
ft 2
= 1957
lbs
ft 2