3. Table of Contents
Table of Contents.......................................................................................................................................... ii
Introduction ................................................................................................................................................. iii
Suggested schedule by major ...................................................................................................................... iii
The Greek..................................................................................................................................................... iv
Equipment..................................................................................................................................................... v
Standard Methods ........................................................................................................................................1
1. Site Investigation and Characterization................................................................................................3
2. Moisture Content..................................................................................................................................6
3. Organic Content....................................................................................................................................8
4. Specific Gravity....................................................................................................................................10
5. Dry Sieve Analysis ...............................................................................................................................12
6. Wet Sieve Analysis ..............................................................................................................................16
7. Hydrometer.........................................................................................................................................18
8. Atterberg Limits ..................................................................................................................................23
9. Soil Classification.................................................................................................................................27
10. Visual Classification.........................................................................................................................33
11. Acid Hardness..................................................................................................................................35
12. Hydraulic Conductivity....................................................................................................................36
13. Consolidation ..................................................................................................................................38
14. Proctor Compaction........................................................................................................................41
15. Field Density....................................................................................................................................43
16. Unconfined Compression................................................................................................................45
17. Triaxial Compression: Unconsolidated Undrained .........................................................................49
18. Direct Shear.....................................................................................................................................55
19. pH and Point of Zero Charge...........................................................................................................60
20. Metals Analysis through Acid Digestion .........................................................................................62
21. Appendix A: Classification Datasheet .............................................................................................65
22. References ......................................................................................................................................66
4. Introduction
This text is intended as a laboratory manual for an educational setting. The methods described
in here are based on standard methods and are intended to introduce the student to tests commonly
conducted in geotechnical engineering. The labs are designed to take up to 2.5 hours of in lab work. The
associated assignments are designed to take around an additional 2 to 3 hours of work outside the lab.
The assignments are intended to allow the student to see the application of the laboratory results in an
engineering design. These methods should not be used to replace standard methods. A textbook is
recommended to supplement this text to provide the necessary background in geotechnical
engineering.
Suggested schedule by major
Week Civil Engineering Environmental Engineering
1 Intro, Lab Safety Intro, Lab Safety
2 Weights and measures, and
moisture content
Weights and measures, and
moisture and Organic Content
3 Specific Gravity Specific Gravity
4 Dry Sieve Analysis Dry Sieve Analysis
5 Wet Sieve and Atterberg
Limits
Wet Sieve and Atterberg
Limits
6 Unconfined Compression and
Field Classification
Hydrometer
7 *Direct Shear Hydraulic Conductivity and
Visual Classification
8 *Consolidation Acid Hardness
9 *Hydrometer pH and Point of Zero Charge
10 *Hydraulic Conductivity Metals Analysis through Acid
Digestion
11 *Triaxial Compression Metals Analysis through Acid
Digestion
12 *Proctor Compaction Proctor compaction
13 Site Investigation and
Characterization
Site Investigation and
Characterization
14 Field Density Field Sampling
*Project rotations will require up to 6 teams per class to conduct a different daily experiment, to accommodate equipment
availability.
5. The Greek
Table 0-1: Greek Alphabet [1].
Upper Case Lower Case Termed Upper Case Lower Case Termed
A Alpha N Nu
B Beta Ksi
Gamma O Omicron
Delta Pi
E Epsilon P Rho
Z Zeta Sigma
H Eta T Tau
Theta Y Upsilon
I Iota Phi
K Kappa X Chi
Lambda Psi
M Mu Omega
7. Standard Methods
Standard methods are a set of instructions commonly accepted as the proper method of
completing a task. Many professional organizations focus solely on developing and maintaining methods
as their primary business. Of the many organizations out there, American Society for Testing and
Materials (ASTM) is commonly referenced in geotechnical testing. Other organizations commonly
referenced are American Association of State Highway and Transportation Officials (AASHTO), Unified
Soil Classification System (USCS), United States Department of Agriculture (USDA), and American
National Standards Institute/ American Water Works Association (ANSI/AWWA). The following standard
methods are used in this text.
ASTM D420-98 Standard Guide to Site Characterization for Engineering Design and Construction
Purposes [2]
USACE EM_1110-2-1906 [3]
ASTM D2216-98 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil
and Rock by Mass [4]
ASTM D2974-14 Standard Test Methods for Moisture, Ash, and Organic Matter of Peat and
Other Organic Soils [5]
ASTM D854-14 Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer
[6]
ASTM D421-85(2007) Standard Practice for Dry Preparation of Soil Samples for Particle-Size
Analysis and Determination of Soil Constants [7]
ASTM D422-63 (reapproved 1998) Standard Test Method for Particle-Size Analysis of Soils [8]
ASTM 4318-10e1 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of
Soils [9]
ASTM D2487-98 Standard Practice for Classification of Soils for Engineering Purposes (Unified
Soil Classification System) [10]
ASTM D2488-93 Standard Practice for Description and Identification of Soils (Visual-Manual
Procedure) [11]
ASTM D3282-93 (Reapproved 1997) Standard Practice for Classification of Soils and Soil-
Aggregate Mixtures for Highway Construction Purposes [12]
ANSI/AWWA B100-09 Granular Filter Media [13]
ASTM D2434-68 (2006) Standard Test Method for Permeability of Granular Soils (Constant
Head) [14]
ASTM D5856-15 Standard Test Method for Measurement of Hydraulic Conductivity of Porous
Material Using a Rigid-Wall, Compaction-Mold Permeameter [15]
ASTM D2435/D2435M-11 Standard Test Methods for One-Dimensional Consolidation Properties
of Soils Using Incremental Loading [16]
ASTM D698-12e2 Standard Test Methods for Laboratory Compaction Characteristics of Soil
Using Standard Effort (12 400 ft-lbf/ft3 (600 kN-m/m3)) [17]
ASTM D1556-90 Standard Test Method for Density and Unit Weight of Soil in Place by Sand-
Cone Method [18]
ASTM D2166 Standard Test Method for Unconfined Compressive Strength of Cohesive Soil [19]
ASTM D2850 Standard Test Method for Unconsolidated-Undrained Triaxial Compression Test on
Cohesive Soils [20]
ASTM D3080 Standard Test Method for Direct Shear Test of Soils Under Consolidated Drained
Conditions [21]
8.
9. 1. Site Investigation and Characterization
Determining the type of soil at a site is essential to designing a successful project. A large
building will require different soil conditions than a dam, while a dam’s ideal soil condition may be
similar to the needs of a landfill. Depending on the type of project we are working on, we need to
determine which soil characteristics we are concerned with. For example, shear strength is a useful
characteristic of soil when looking at slope stability and bearing capacity.
Readings
ASTM D420-98 [2]
General Literature review
Materials
Computer with internet access
Procedure
There are many sources available which can help you gather the required information you need to
conduct a thorough site investigation. Not a single source will provide you with all the information you
need. The USDA Web Soil Survey (WSS) is a good place to start your investigation. Follow the link below
to the USDA Web Soil Survey website [22].
http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm
Once on the website you should see the images in Figure 1-1.
Figure 1-1: USDA Web Soil Survey Homepage [22].
At the home page you will be able to find tutorials and instructions. To begin, click on the green “Start
WSS” button at the top center of your screen. Find the area you would like information on and select
your Area of Interest (AOI). Go to the “Soil Map” tab and report the types of soils in our AOI. Now go to
the “Soil Data Explorer” tab. Explore the “Suitabilities and Limitations for Use” and “Soil Properties and
Qualities” tabs. You can download data and also add it to a free shopping cart for exporting your data.
10. Other sources can also provide good historical data. The United States Geological Survey (USGS),
local transportation or engineering departments, and local municipalities may also have good historical
data. This historical data can help reduce the costs associated with subsurface exploration by informing
you of important characteristics of the soil, such as depth to bedrock or depth to the water table. The
type of project you are working on is also important. The height of a structure will determine the depth
to which you need to explore. Different project types also have different spacing requirements between
sampling locations. Local engineering codes may specify the requirements for each project type. Each
project type will also require the soil is tested for different properties. Hydraulic conductivity may need
to be tested for one project but not for another. Table 1-1 below will guide your project requirements.
Table 1-1: Sampling Plan Flow chart.
Project Types of
Sampling
Method
Depth of
Sampling
Distance
between
Samples
Total Number
of Samples
Types of
Laboratory
Testing
Recommended
Road
Highway
Single story
structure
2-story
structure
Dams
(Hydraulic
barriers)
Stadium
Table 1-1 is a guide and you may want to include additional information for your project.
Assignment
This is a multi-part assignment. Just like a real site investigation you want to prepare a plan
before going out into the field and spending big money on collecting your samples. Your first part will
include you using the WSS. Using WSS, you will be able to find a general overview of the soils present at
your location. For this location, you will design a sampling plan for a site which is 5000 acres at a
location in the continental United States. Determine the estimated cost of your exploration. Make
appropriate recommendations to your client. This site will include roads, single family homes, multi-unit
housing, commercial buildings and a large soccer stadium. The stadium should have a capacity of 50,000
spectators, restaurants, parking structures, and all supporting facilities. Drainage, retention and
detention (this will include a dam structure and channel slopes) must also be taken into consideration.
This is a planned community, planned entirely around soil properties. Your general Platting Plan is
shown in Figure 1-2 below.
11. Figure 1-2: Platting Plan.
The Platting Plan assumes there will be highways between the large zone regions and small roads within
as necessary. The Multi-Use zone is the city center and will need to accommodate 10 story plus high
rises.
Part 1
Our Area of Interest (AOI) must be 5000 acres and located within the Continental United States.
Report all the types of Surface Texture soils expected within this region. When reporting your soil type
data include the unit symbols, names of soil, general location within AOI and the estimated amount
within AOI. Report all the relevant information for our project. The WSS is only a small part of your
literature review process before you go out and conduct sampling. Although WSS is provided by the
USDA and is primarily focused on the agricultural perspective of soils, our project does not focus on this
aspect.
Part 2
Conduct a literature review using library resources, web sources, local municipalities, textbook
or any other resource you are able to find and develop a site investigation plan. Some government
agencies and municipalities provide guidance for developing a sampling plan. As part of your sampling
plan you will have to decide where and how many samples must be taken, what type of sampling
technique should be used, depth of samples and what lab tests must be completed on the soils.
Remember, sampling and exploration is expensive. Minimize the cost to your client, but protect yourself
from liability and sample sufficiently.
Stadium
Commercial
Commercial
Residential
Commercial Residential
Happy Lake
Multi-Use
12. 2. Moisture Content
In this first lab you will be using two types of scales while collecting data for moisture content.
Provide a brief description of the soil used in your experiment.
Readings
USACE EM 1110-2-1906 Appendix I [3]
USACE EM 1110-2-1906 Appendix II [3]
ASTM D2216-98 [4]
Materials
5 moisture cans
Evaporating dish
Electronic scale
Balance beam scale
Oven (approx. 105 C)
Weights
China Marker
Tongs
Oven gloves
Procedure
This procedure is separated into three main parts. This lab serves as an introduction to basic lab
practices and methods which will be used throughout this course. Weights and Measures is intended to
familiarize you with using different scales. Moisture Content is a criteria which is needed throughout
numerous tests in Geotechnical Engineering.
Weights and Measures
Be sure to choose the correct size scale. The size of the sample will help you determine the
correct scale. Two size scales are commonly used in the lab. A microscale which is designed to weigh up
to 5 kg and displays readings down to 0.01 g intervals. The larger scale goes up to 75 kg and displays
readings down to 0.1 g. Depending on the size of the sample an extra decimal place may influence the
results significantly.
Triple Beam
Triple Beam Balances should first be zeroed. Ensure the scale is clean and all parts are
accounted for. The weight hanger should be attached to the end of the balance. The weights on the
beams should be returned to their zero location. A screw underneath the load platform can be adjusted
to level the scale, or a small weight on the non-graduated beam can also be adjusted. The beam should
stop moving before samples are weighed. The weights provided with the triple balance beam are
labeled in accordance with the lever ratio of the scale. Make sure you have the correct weights.
Electronic Scale
Electronic scales should also be balanced and zeroed before use. The electronic scales can be
balanced by adjusting the legs and centering the bubble on the level. Make sure the scale is sitting
directly on a flat and stable surface. The scale should then be zeroed. Most electronic scales can be
zeroed with some objects still on the scale, this makes adding materials or mixing materials easier.
13. Moisture Content
Collect 5 moisture cans and weigh them on the electronic scales and on the balance beam to
determine the weight of each can (Wc). Use heat resistant evaporating dishes when Organic Content is
also needed. Weigh all your initial sample weights and moisture can (W1) with both the balance beam
and an electronic scale. Be sure to label each of your moisture cans, a China Marker works well for
marking most surfaces. Make appointment with instructor to collect dried sample weights (W2). Samples
must dried for a minimum of 16 hrs. Table 2-1 below provides workspace for Moisture Content.
Table 2-1: Moisture content worksheet.
Moisture Can
Weight of can (Wc)
Weight of sample and can
(W1)
Weight of dried sample and
can (W2)
Weight of moisture (W1-
W2)
Weight of dried sample
(W2-Wc)
Moisture content, (), %:
Equation 2-1 below calculates the moisture content of the sample.
Equation 2-1: Moisture Content.
𝜔 =
𝑊1 − 𝑊2
𝑊2 − 𝑊𝑐
∗ 100%
Assignment
Your Supervisor at Dirty Joe Excavation Inc. needs you to determine the moisture content of a
soil sample. The soil sample has an optimum unit weight at 14% moisture content as was determined by
a Standard Proctor test. What is the current moisture content of the soil? What are you going to
recommend your supervisor do with the soil to obtain the optimum moisture content? What is the
percent difference of each sample between the different scales?
14. 3. Organic Content
Organic content of soil can be an important part of classifying soil. The typical engineering
properties of organic soils can make them undesirable for certain projects. The organic content of soil
may also increase the Cation Exchange Capacity (CEC) of soils and complicate the dispersion and
transport modelling of contaminants.
Readings
ASTM D2974-14 [5]
Materials
5 heat resistant evaporating dishes
Electronic scale
Oven (105 C)
Oven (440 C)
Marker
Tongs
Oven Gloves
Procedure
Organic Content is determined in series to Moisture Content. Ensure the sample is thoroughly
dried before starting test. When Organic Content is needed heat resistant evaporating dishes should be
used. Heat resistant evaporating dishes are generally made from high-silica ceramic. Obtain the weight
of an evaporating dish (Wd). Determine the moisture content of the samples and use the weight of the
dried sample and dish (W2). Place the evaporating dish in the Muffle Furnace at 440 C for at least 1
hour. Remove the evaporating dish from the muffle furnace with metal tongs and allow the evaporating
dish to cool to room temperature. Obtain the weight of the sample and evaporating dish (W3). Table 3-1
below provides the workspace for determining Organic Content.
15. Table 3-1: Moisture content worksheet.
Moisture Can
Weight of dish (Wd)
Weight of dried sample and
dish (W2)
Weight of sample and dish
after 440 C (W3)
Weight of organic material
(W2-W3)
Weight of burnt sample
(W3-Wd)
Organic Content, (OC) %:
Use Equation 3-1 below to determine Organic Content.
Equation 3-1: Organic Content.
𝑂𝐶 =
𝑊2 − 𝑊3
𝑊3 − 𝑊𝑑
∗ 100%
OC: Organic Content
Assignment
In accordance to USCS Assessment of Soil Properties Based on Group Symbols discuss the
engineering properties of soil. Discuss the retardation effect of organic soils when modeling chemical
transport. Use a minimum of four different sources.
16. 4. Specific Gravity
Specific gravity is an intensive property of material. In practice this property can be used for
settling velocity and other analysis for engineering design. Your text gives you ranges of specific gravity
for different soil types.
Readings
USACE EM_1110-2-1906, Appendix IV [3]
ASTM D854-14 [6]
Materials
500 ml volumetric flask
3 medium sized evaporating dishes
Plastic squeeze bottle
Funnel
DI water
Balance
Drying oven
At least 3 types of sand
Procedure
Weigh the volumetric flask to obtain Wf. Weigh and label the evaporating dishes (Wd). Fill the
volumetric flask with water and obtain the weight (W1). The bottom of the meniscus should be flush
with the volume mark on the neck of the flask. Obtain between 50 grams and 100 grams of each of the 3
soil types provided. Pour out approximately one third of the water in the volumetric flask. Pour the first
soil sample into the volumetric flask, then refill the volumetric flask with water to the 500 ml mark.
Apply a vacuum to the volumetric flask and sample. Periodically swirl the sample to agitate the air
content. After there are no more bubbles, refill the water to the 500 ml mark. Making sure the outside
and neck of the volumetric flask is dry, weigh the sample in the volumetric flask to obtain W2. To empty
the flask swirl the sample and with your thumb on the opening invert the volumetric flask and allow the
sample to settle into the neck of the volumetric flask. Once the sample has settled, slowly empty the
sample into an evaporating dish. Place sample in drying oven. Repeat steps for the two other sample
soils. After all three samples have been placed in the drying oven make appointment with your
instructor to weigh your dried samples (Ws). Table 4-1 below provides some work space for the lab’s
data acquisition.
17. Table 4-1: Specific Gravity Worksheet.
Variable Sample 1: Sand Sample 2: Gravel Sample 3: Anthracite
Weight of flask, Wf (g)
Weight of evap. Dish,
Wd (g)
Weight of flask and
water, W1 (g)
Weight of flask water
and sample, W2 (g)
Weight of dried
sample, Ws (g)
Weight of water
volume equivalent to
volume of sample,
(Ww), (g)
Specific gravity, (Gs)
Table 4-1 provides space to record your raw data. Use Equation 4-1 below to determine the weight
equivalent of the volume of water to the volume of solids.
Equation 4-1: Weight of water volume equivalent to volume of sample.
𝑊𝑤 = (𝑊1 + 𝑊𝑠) − 𝑊2
Equation 4-2 below will determine specific gravity.
Equation 4-2: Specific Gravity.
𝐺𝑠 =
𝑊𝑠
𝑊𝑤
=
𝜌𝑠
𝜌 𝑤
=
𝛾𝑠
𝛾 𝑤
: Density of material
: Unit weight of material
Assignment
Joe Flow from Wastewater Flow Inc. wants to verify his new wastewater treatment filter will
stratify properly after back washing his filter. According to his design the top layer would be the Sand,
middle layer would be Gravel and the bottom layer the Anthracite. The denser material would settle
first. Will the Joe Flow filter design function as intended? What other methods can be used to determine
specific gravity?
18. 5. Dry Sieve Analysis
Dry sieve analysis determines the particle size distribution of coarse soils, sometimes also
referred to as a texture analysis. The Particle size distribution data is used to classify soil in accordance
with USDA, USCS, AASHTO, ANSI and other systems. The classification of soils helps engineers determine
if a particular soil will meet the design requirements for a project. Projects such as a water filter,
foundation, landfill cover, roads and many other types of projects require certain types of properties
relating to particle size distribution.
Readings
USACE EM_1110-2-1906 Appendix V [3]
ASTM D421 [7]
Materials
Sieves (#4, 10, 20, 40, 60, 140, 200, bottom pan and lid)
o For Granular Filter Material use Sieves #10, 12, 14, 16, 18, 20, and 25
Wire sieve brush (For sieves larger than #60)
Paint brush (for sieves #60 and smaller)
Mortar and pestle
Mechanical shaker
Balance accurate to 0.1 grams
Any soil
Procedure
We will conduct two sieve analysis on the same soil type from the site mentioned in the assignment.
Each sample size will be approximately 500g. Use a pestle and mortar to break down clumps in the soil,
do not attempt to break rocks in the mortar. Weigh your sample, Wi. Clean each sieve as instructed in
the Materials list above, then obtain the weight of each sieve and pan. Stack the sieves in order from
Pan, #200, #140…#4. Place sample in the top sieve, cover with lid. Place the nest of sieves in one of the
mechanical shakers and turn on the shaker for no less than 6 minutes. Weigh each sieve with the sample
retained. Repeat these steps for your additional tests. Fill out Table 21-1 in the Appendix using the
following equations. Equation 5-1 will calculate the percent retained for Column 6 of Table 5-1.
19. Table 5-1: Sieve analysis worksheet.
Sieve # Sieve
opening
(mm)
Mass of
sieve, A
(g)
Mass of
Sieve and
retained
sample, B
(g)
Mass of
sample,
Wn (g)
Percent of
mass
retained,
Rn
Cumulative
percent
retained,
∑Rn
Percent
finer,
(100-∑Rn)
4 4.75
10 2
20 0.85
40 0.425
60 0.25
140 0.106
200 0.075
Pan NA
∑ xx xx xx Wts=
Equation 5-1: Percent of Mass Retained.
𝑅 𝑛 =
𝑊 𝑛
𝑊𝑡𝑠
× 100
Rn= % retained on individual sieve
Wn= Mass on individual sieve
Wts= Mass of total sample
Equation 5-2 will calculate the cumulative percent retained on each successive sieve for Column 7 in
Table 5-1.
Equation 5-2: Cumulative Percent Retained.
𝐶𝑢𝑚𝑢𝑙𝑎𝑡𝑖𝑣𝑒 % 𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑 = ∑ 𝑅 𝑛
𝑖=𝑛
𝑖=1
Equation 5-3 will calculate the percent finer for Column 8 in Table 5-1.
Equation 5-3: Percent Finer.
% 𝑓𝑖𝑛𝑒𝑟 = 100 − ∑ 𝑅 𝑛
𝑖=𝑛
𝑖=1
Equation 5-4 will calculate the total mass lost during the analysis.
Equation 5-4: Mass loss during test.
𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 𝑑𝑢𝑟𝑖𝑛𝑔 𝑎𝑛𝑎𝑙𝑦𝑠𝑖𝑠 (%) =
𝑊𝑖 − 𝑊𝑡𝑠
𝑊𝑖
× 100
Wi= Initial sample Mass
20. A mass loss of less than 2% will be acceptable for you to continue with your analysis. At this point you
should have two sets of sieve analysis data. Use the percent finer data and the sieve opening diameters
to create a semi-logarithmic graph. Figure 5-1 below provides an example graph of a particle size
distribution.
Figure 5-1: Example PSD curve.
Using the data you are able to obtain from this graph you can now use Equation 5-5 to calculate the
Coefficient of Uniformity.
Equation 5-5: Coefficient of Uniformity.
𝐶 𝑢 =
𝐷60
𝐷10
Cu= Coefficient of Uniformity
D60= maximum diameter of particles finer than 60%
D10= maximum diameter of particles finer than 10%
Equation 5-6 calculates the Coefficient of Curvature.
Equation 5-6: Coefficient of Curvature.
𝐶 𝑐 =
𝐷30
2
𝐷60 × 𝐷10
Cc=Coefficient of Curvature
D30= maximum diameter of particles finer than 30%
21. Using these data complete the assignment below.
Assignment
Dirt Diggars Inc. has hired you to classify the soil in accordance with AASHTO, USCS, USDA, and
ANSI/AWWA standards. Your client is considering a new site for a park with a lake, roads, and shops.
Determine if the soils can be used in a hydraulic barrier, subgrade for roads, or fill for the structures. Can
the Client market the soil as a granular filter media as specified by ANSI/AWWA? Recommend any
additional testing which may need to be conducted to determine the client’s needs.
22. 6. Wet Sieve Analysis
Extremely fine particle have a tendency to clump together and may sometimes have difficulty
passing the #200 sieve. To continue the classification of soils we need to determine the percent of soil
passing the #200 sieve. We will be using the Wet Sieve Analysis to determine the percent of fines in our
material.
Readings
USACE EM_1110-2-1906 Appendix V [3]
ASTM 421 [7]
Materials
Sieves (#10, #40, #60, #140, #200, Pan and Lid)
Wire sieve brush (For sieves larger than #60)
Paint brush (for sieves #60 and smaller)
Mortar and Pestle
Mechanical shaker
Squeeze bottle with water
8” evaporating dish
(2) 4” evaporating dish
Drying oven
Balance accurate to 0.1 grams
High Clay content Soil
Procedure
Obtain a soil sample of approximately 300 grams. Pulverize the sample until there are no more
clumps in the sample. You will not be able to crush rocks in the mortar. Prepare your nest of sieves the
same way you did for the Dry Sieve Analysis. Place the sample in your nest of sieves. Mechanically shake
the nest of sieves for 6 minutes. Weigh your sieves and discard all material except the material retained
on the #200 sieve (W#200). Use Table 6-1 for your raw data.
Table 6-1: Sieve Analysis Worksheet.
Sieve # Sieve
opening
(mm)
Mass of
sieve, A
(g)
Mass of
Sieve and
retained
sample, B
(g)
Mass of
sample,
Wn (g)
Percent of
mass
retained,
Rn
Cumulative
percent
retained,
∑Rn
Percent
finer,
(100-∑Rn)
4 4.75
10 2
20 0.85
40 0.425
60 0.25
140 0.106
200 0.075
Pan NA
∑ xx xx xx Wts=
23. At the sinks carefully rinse the #200 sieve with water above the 8” evaporating dish until the water
leaving the sieve is clear. Now gently collect the sample left in the #200 sieve on the edge of the sieve.
Weigh an empty 4” evaporating dish. Using the squeeze bottle to wash the soil sample into the
evaporating dish. Place evaporating dish in drying oven. The weight of sample remaining (Wd) can now
be determined. The weight of material finer than #200 (Wf) can be determined using Equation 6-1
below.
Equation 6-1: Weight finer than #200.
𝑊 𝑓 = 𝑊 𝑃𝑎𝑛 + 𝑊#200 − 𝑊 𝑑
WPan=Mass retained on pan
Use the Dry Sieve Analysis method for any intermediate steps.
Assignment
Lunar Railroads has hired your firm to classify a soil from a bridge project crossing Wild Muddy
River. You will need to classify the soil and provide an initial determination of whether the soil could be
good for foundation material. Use AASHTO and USCS classification systems. You will need to conduct the
Atterberg Limits as well in order to complete this classification.
24. 7. Hydrometer
Part of soil classification is determining the particle distribution of the material. For material
smaller than the #200 sieve the Hydrometer test method is used. This method will place the soil into
solution and use Stoke’s Law to determine the effective particle diameter. The hydrometer test is
effective down to 1x10-4
mm [23].
Readings
USACE EM_1110-2-1906 Appendix V [3]
ASTM D422-63 [8]
Materials
Atterberg Soil
Nest of Sieves
Sieve brushes
Mortar
Pestle
Mechanical shaker
Hydrometer 152H
1000 CC Cylinder (2x)
#13 stopper
Thermometer
Squeeze bottle
10” evaporating dish
Timer
Materials excluded from lab:
Sodium Hexametaphosphate
DI water
Mixer
Procedure
Conduct a standard sieve analysis on approximately 100 grams of soil with a high clay content.
Refer to the Dry Sieve procedures as needed. Table 7-1 below provides the worksheet for the sieve
analysis.
25. Table 7-1: Sieve analysis worksheet.
Sieve # Sieve
opening
(mm)
Mass of
sieve, A
(g)
Mass of
Sieve and
retained
sample, B
(g)
Mass of
sample,
Wn (g)
Percent of
mass
retained,
Rn
Cumulative
percent
retained,
∑Rn
Percent
finer,
(100-∑Rn)
4 4.75
10 2
20 0.85
40 0.425
60 0.25
140 0.106
200 0.075
Pan NA
∑ xx xx xx Wts=
Use the material collected on the pan for the Hydrometer analysis. Fill one 1000 CC cylinder with water
and gently lower the hydrometer into the water. After the hydrometer stops moving take a reading
from the device, this is your zero (R0). Obtain the temperature of your water. Obtain the moisture
content of your soil by using a representative portion of your sample. The remaining sample (W2) will be
used during your analysis.
Slowly mix water and soil in evaporating dish until the solution can be poured into the 1000 CC
flask. Use the squeeze bottle to wash any remaining soils from the evaporating dish into the cylinder.
Once all the soil has been added to the cylinder, fill the cylinder to the 1000 CC volume mark with water.
Place the stopper securely on the cylinder and mix the solution by holding the stopper tightly and
inverting the cylinder completely and back upright for a period of 1 minute. Immediately after setting
down the cylinder, gently lower the hydrometer into the solution and allow it to stabilize. Take readings
at 0.5, 1, 2, 5, 10, 20, 40 and 80 minutes. Observe the temperature during each reading. Table 7-2 below
provides the worksheet for the Hydrometer analysis.
Table 7-2: Hydrometer data.
Time (min) Hydrometer
Reading (R)
Temperature (C) Diameter
(mm)
Percent
Finer for
Hydrometer
(%H)
Percent
Finer for
Total
Sample
(%T)
0.5
1
2
5
10
20
40
80
Using Equation 7-1 below, calculate the effective diameter of the particles.
27. Table 7-4: Hydrometer 152H length readings [8].
Actual
Readin
g (R)
Effectiv
e
Length,
(L)
Actual
Reading
, (R)
Effectiv
e
Length,
(L)
Actual
Readin
g (R)
Effectiv
e
Length,
(L)
Actual
Readin
g (R)
Effectiv
e
Length,
(L)
Actual
Readin
g (R)
Effectiv
e
Length,
(L)
0 16.3 12 14.3 24 12.4 36 10.4 48 8.4
1 16.1 13 14.2 25 12.2 37 10.2 49 8.3
2 16 14 14 26 12 38 10.1 50 8.1
3 15.8 15 13.8 27 11.9 39 9.9 51 7.9
4 15.6 16 13.7 28 11.7 40 9.7 52 7.8
5 15.5 17 13.5 29 11.5 41 9.6 53 7.6
6 15.3 18 13.3 30 11.4 42 9.4 54 7.4
7 15.2 19 13.2 31 11.2 43 9.2 55 7.3
8 15 20 13 32 11.1 44 9.1 56 7.1
9 14.8 21 12.9 33 10.9 45 8.9 57 7
10 14.7 22 12.7 34 10.7 46 8.8 58 6.8
11 14.5 23 12.5 35 10.6 47 8.6 59 6.5
Use Equation 7-2 below to determine Percent Finer.
Equation 7-2: Percent Finer [3].
𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝐹𝑖𝑛𝑒𝑟 𝑏𝑦 𝑤𝑒𝑖𝑔ℎ𝑡 =
𝑅𝑎
𝑊𝑠
× 100
R: Direct reading from hydrometer
WS: Dry Weight of the soil (Refer to Equation 7-3)
a: Specific Gravity correction (Refer to Table 7-5)
Table 7-5: Specific Gravity correction for percent finer [8].
Specific Gravity Correction Factor (a)
2.45 1.05
2.50 1.03
2.55 1.02
2.60 1.01
2.65 1.00
2.70 0.99
2.75 0.98
2.80 0.97
2.85 0.96
2.90 0.95
2.95 0.94
The Dry weight of your sample can be determined by Equation 7-3 below.
28. Equation 7-3: Dry weight of soil.
𝑊𝑠 =
𝑊2
1 + 𝜔
: Moisture content
The Percent Finer for the total sample is determined by Equation 7-4 below.
Equation 7-4: Total Percent Finer.
% 𝑇 =
% 𝐻 × %<#200
100
%<#200: The percent of the total sample finer than the #200 sieve.
The sieve analysis data and the Hydrometer data must now be combined. Use Table 7-6 to combine the
Particle Size Distribution (PSD) data.
Table 7-6: Combined PSD data.
Particle Diameter (mm) Percent Finer (%T)
4.75
2
0.85
0.425
0.25
0.106
The diameter for the #200 sieve has been left blank due to the fact that the effective diameter of some
particles will be greater than the #200 diameter. The data in Table 7-6 should be plotted on a semi
logarithmic graph as described in the Dry Sieve Analysis. The Wet Sieve data and the Hydrometer data
may be plotted on the same graph, but shown separately by inputting the data in the graph in separate
series.
Assignment
Pottery Inc. is requesting your company classify a soil sample from Muddy River according to
USCS. The Atterberg limits are reported by a colleague as PI is 18 and the LL is 30. Report the particle
distribution curve. What is the effective size? What is the coefficient of curvature? What is the
Coefficient of uniformity? What sources of error are present in the way the method was conducted?
Report the percent finer of the important sizes, #4, #10, #40, #200, 0.074 mm, 0.005 mm and 0.001 mm
[8]. Display your data in accordance with the data sheet in Appendix A.
29. 8. Atterberg Limits
The behavior of soils can be used to determine the Atterberg Limits of soil. We will determine the Plastic
Limit (PL) and Liquid Limit (LL) of our sample of soil using the Atterberg limit tests. Shrinkage Limit will
not be discussed here.
Readings
USACE EM_1110-2-1906 Appendix III [3]
ASTM D4318-10e1 [9]
Materials
Sieve #40, Pan and Lid)
Wire sieve brush (For sieves larger than #60)
Mortar and Pestle
Casagrande LL device (B)
Casagrande Cup (A)
Grooving tool (D, E)
(8) Moisture cans
Spatula
Squeeze bottle with water
Glass plate (C)
8” evaporating dish
(2) 4” evaporating dish
Drying oven
Balance accurate to 0.1 grams
Atterberg Clay Soil
Figure 8-1: Atterberg Limits Equipment.
30. Procedure
Most soils will have a lower Plastic limit than Liquid Limit and it is recommended the Plastic
Limit test is conducted before the Liquid Limit. Soils with a negative Plasticity Index are considered to be
Non-Plastic and the Plasticity Index is reported as 0.
Plastic Limit
Obtain a soil sample of 250 grams finer than the #40 sieve. Weigh and mark 8 moisture cans. Slowly add
water to approximately half your sample until the sample is stiff and has a putty-like consistency. Be
sure to mix consistently. Roll an ellipsoid approximately ½ inch in diameter. Roll the ellipsoid on the
glass plate into a cylindrical thread. When the thread breaks at 1/8 inch in diameter collect a sample of
the cracked soil and obtain the moisture content. If the sample cracks at a diameter greater than 1/8
inch, the sample is too dry. If the sample is smaller than 1/8 inch before it cracks, the sample is too wet.
The Plastic Limit can be obtained using Equation 8-1 below.
Equation 8-1: Plastic Limit.
𝑃𝐿 =
𝑊𝑚 − 𝑊𝑑
𝑊𝑑 − 𝑊𝑐
× 100
Wm= Weight of can and moist sample
Wd= Weight of can and dry sample
Wc= Weight of can
Repeat previous steps two more times and average your results for your PL. Use Table 8-1 below to
record your results.
Table 8-1: Plastic Limit Worksheet.
Moisture Can:
Weight of can, (g)
Weight of can and moist sample,
(g)
Weight of can and dry sample, (g)
Liquid Limit
Clean, test and calibrate your Casagrande device. The cup should fall exactly 1 cm onto the base. Figure
8-2 below shows the way the grooving tools can be used to calibrate the Casagrande device.
31. Figure 8-2: Casagrande device, tools and sample.
Add a small amount of water to your sample. Fill the Casagrande cup with sample to a depth of 10 mm.
Use the Spatula to smooth the surface of your sample. Now use the grooving tool to form a trench down
the center of your sample. Once your sample is prepared as it is in Figure 1 you can turn the crank at 2
rotations per second. When the gap in the soil closes stop turning the crank. Record the number of
drops (N), then obtain the moisture content. If N<15, the soil is too wet. If N>35, the soil is too dry.
Obtain at least 4 values for N so you can interpolate N=25. For this multistep method plot your data with
the moisture content on the y-axis on the arithmetic scale, and the drop values on the x-axis on a
logarithmic scale. At 20<N<30 you will be able to calculate your liquid limit Using Equation 8-2.
Equation 8-2: Liquid Limit.
𝐿𝐿 = 𝜔 𝑁 (
𝑁
25
)
0.121
ωN= Moisture content
From your graph, also determine the Flow Index (FI) using Equation 8-3.
Equation 8-3: Flow Index.
𝐹𝐼 =
𝜔1 − 𝜔2
𝑙𝑜𝑔𝑁2 − 𝑙𝑜𝑔𝑁1
Table 8-2 below can be used to record your data.
32. Table 8-2: Liquid Limit Worksheet.
Sample number:
Moisture can:
Weight of can, (g)
Weight of can and moist
sample, (g)
Weight of can and dry
sample, (g)
Number of drops, N
The Liquid Limit Data is generally plotted on a semi-logarithmic graph as can be seen in Figure 8-3
below.
Figure 8-3: Liquid Limit graph.
The Liquid Limit is reported as the moisture content at 25 drops from the Casagrande Device.
Assignment
Refer to the Wet Sieve Analysis to complete this assignment.
33. 9. Soil Classification
There have been many attempts at classifying soil to help in determining whether a soil may be
of some beneficial use. The methods described below are some of the methods commonly used.
USCS
ASTM D2487-98 [10]
Figure 9-1: Flow Chart Identifying Inorganic Fine-Grained Soil (50 % or more fines) [24].
35. Table 9-1: General soil characteristics of soils for Group Symbols [26].
Group
Symbol
Compaction
Characteristics
Compressibility
and Expansion
Drainage
and
Hydraulic
Conductivity
Value as Fill Value as
pavement
subgrade
Value as
base
coarse for
pavement
GW Good Almost none Good
Drainage
Very Stable Excellent Good
GP Good Almost none Good
Drainage
Reasonably
Stable
Excellent
to Good
Fair to
Poor
GM Good Slight Poor
Drainage
Reasonably
Stable
Excellent
to Good
Fair to
Poor
GC Good to Fair Slight Poor
Drainage
Reasonably
Stable
Good Good to
Fair
SW Good Almost none Good
Drainage
Very Stable Good Fair to
Poor
SP Good Almost none Good
Drainage
Reasonably
Stable
when
dense
Good to
Fair
Poor
SM Good Slight Poor
Drainage
Reasonably
Stable
when
dense
Good to
Fair
Poor
SC Good to Fair Slight to
Medium
Poor
Drainage
Reasonably
Stable
Good to
Fair
Fair to
Poor
ML Good to Poor Slight to
Medium
Poor
Drainage
Fair
Stability
Fair to
Poor
Do Not
Use
CL Good to Fair Medium No Drainage Good
Stability
Fair to
Poor
Do Not
Use
OL Fair to Poor Medium to
High
Poor
Drainage
Unstable Poor Do Not
Use
MH Fair to Poor High Poor
Drainage
Fair to Poor
Stability
Poor Do Not
Use
CH Fair to Poor Very High No Drainage Fair
Stability
Poor to
Very Poor
Do Not
Use
OH Fair to Poor High No Drainage Unstable Very Poor Do Not
Use
Pt Not Suitable Very High Fair to Poor Do Not Use Do Not Use Do Not
Use
36. AASHTO
ASTM D3282-93 [12]
Figure 9-4: AASHTO Group Classification for Excellent to Good Subgrade [27].
Figure 9-5: AASHTO Group Classification for Fair to Poor Subgrade [27].
38. Others
ANSI/AWWA B100-09 [13]
Table 9-2: Granular Filter Media basic requirements [13].
Filter Media Specific
Gravity
Acid Solubility
(%)
Mohrs
Hardness
Finer than
0.074 mm (%)
Organic
Content (%)
Anthracite >1.4 <5 >2.7 <1 <0.5
Silica Sand >2.5 <5 <2
High-density
Sand
>3.8 <5 <2
Support Gravel >3.8 <1 <0.5
<2.36
mm
<5
>2.36
mm -
<25.4
mm
<17.5
>25.4
mm
<25
Table 9-3: Granular Filter Media size requirements [13].
Filter Media Effective Size, D10
(mm)
Uniformity
Coefficient Cu
Anthracite 0.6-1.6 <1.7
Silica Sand 0.35-0.65 <1.7
High-density Sand 0.18-0.6 <2.2
39. 10. Visual Classification
You need to develop the ability to quickly make an educated guess as to what type of soil you
are dealing with. This method will provide some guidance to obtaining a rough classification of soils
when a laboratory or equipment is not readily available. Use the same source of soil used for the dry
sieve analysis for comparison.
Materials
Large Pan
Water
100 grams of soil
Readings
ASTM D2488-93 [11]
Procedure
Refer to the standard method to complete this procedure.
Figure 10-1: Visual Classification flowchart for course grained soils [11].
40. Figure 10-2: Visual Classification flowchart of fine grained soils [11].
Assignment
You have completed a sieve analysis on the same materials. Considering the potential
differences between soils when classifying two samples next to each other. How does your visual
classification compare to your dry sieve analysis? Can this material be used as subgrade? Can this
material be used as daily cover in a landfill? What are your recommendations to your client?
41. 11. Acid Hardness
Acid hardness or Acid Solubility is a requirement used when determining whether a material is
suitable for use in a water filtration system. Other methods for testing hardness include Mohs Hardness.
Readings
ANSI/AWWA B100-09 [13]
Materials
1:1 HCl Acid 32 mL
Distilled water
Drying oven
Desiccator
Scale (0.1g)
250 mL Flask
10 g of fine grained sand, anthracite, and gravel
Hazardous waste generated
Acid solution
Procedures
Obtain a sample of each type of oven dried soil. Obtain the initial weight (Wi). Place sample in
beaker and slowly pour 32 mL of 1:1 HCl Acid over the sample or until the sample is fully inundated.
Allow the material to soak for 30 minutes or until there is no more visible reactions. Thoroughly rinse
your sample and place in the drying oven at 110 C. Weigh the dried sample to determine the mass lost
(Wf). Use Equation 11-1 to determine the Acid Solubility.
Equation 11-1: Acid Solubility [13].
𝐴𝑐𝑖𝑑 𝑆𝑜𝑙𝑢𝑏𝑖𝑙𝑖𝑡𝑦 (%) =
𝑊𝑓
𝑊𝑖
× 100
Assignment
Joe Flow from Wastewater Flow Inc. would like you to determine if the material will meet the
ANSI/AWWA Granular Filter Media requirements for Acid Solubility. What other engineering
applications would need you to determine Acid Solubility?
42. 12. Hydraulic Conductivity
Determining the Hydraulic conductivity of soils can be done using several different methods. For
coarse grained materials you will use the constant head method, for fine grained soils you would use the
falling head method. We will be utilizing Darcy’s Law in our constant head permeability test.
Readings
USACE EM_1110-2-1906 Appendix VII [3]
ASTM D2434 [14]
ASTM D5856 [15]
Materials
Permeameter
Graduated cylinder (250 mL)
Graduated cylinder (1000 mL)
Calipers
Measuring tape or yard stick
Largemouth funnel
Large spoon
Paint brush
Tamper
2.5 inch porous stones (2)
Timing device
8 inch evaporating dish with gravel sample
Water
Vacuum source
Air source
Procedure
You will be using a gravel for your constant head permeameter experiment. Return soil to the
original container after testing is completed. Place a porous stone in the bottom of the permeameter by
tilting the permeameter slightly as to not damage the stone. Place the soil into the permeameter up to
within 2 inches from the top of the chamber. Gently tamp the gravel in place and level, use only the
weight of the tamper and do not apply any force. Place the second porous stone on top of the gravel
sample. Using the paint brush, clean of the black ledge on the top of the permeameter chamber. Make
sure there are no soil particles on either the top of the chamber or on the cap of the chamber. Attached
the spring to the bottom of the cap. Place the cap on the chamber and make sure a pressure is applied
to the porous stone. This pressure will prevent movement of the material. Clamp down the cap by
tightening the screws at an equal rate. Do not over tighten, this will damage the device.
Keeping the valves closed, the switch is perpendicular to the direction of flow. Attach one hose
to the upper inflow valve and attach the other end of the hose to a vacuum source, do not turn on the
vacuum. Place the constant head funnel at a desired height and attach a hose between the funnel and
the bottom outflow valve. Fill the constant head funnel with water. Open the bottom outflow valve and
allow the chamber to fill with water, fill the constant head funnel as needed. Turn on the vacuum and
carefully open the top inflow valve to remove air from the chamber. When water appears in the vacuum
tube close the inflow valve and turn off the vacuum. Do not let water into the vacuum system. Close the
bottom outflow valve and remove the constant head hose. Attach the constant head hose to the top
inflow valve. Attach a second hose to the bottom outflow valve. Fill the constant head funnel with water
43. and make sure there are no air bubbles in the hose or chamber. Use the brass bleed valve to work out
the air bubbles. Do not use a tool on the brass bleed valve.
Keep the water in the funnel at a constant level for the duration of the test. Open the bottom
outflow valve and allow the water to flow into the sink. When the flow is steady use the 250 mL
graduated cylinder to collect a volume for a duration of time. Use Equation 12-1 to determine the
Hydraulic Conductivity (k).
Equation 12-1: Hydraulic Conductivity [29].
𝑘 =
𝑉𝐿
𝐴𝑡ℎ
Where:
V= Volume of water collected
L=Length water traveled from source
A= Area of sample perpendicular to flow
t= time it took to collect volume of water
h= change in hydraulic head from top of funnel to bottom outflow valve
You will only need to prepare the sample and chamber once, but you will collect 5 different
volumes of water.
Assignment
You will conduct 5 constant head experiments and report the average of your results. What
statistical confidence do you have in your analysis? What is the standard deviation for your samples?
Report the proper significant figures.
44. 13. Consolidation
The consolidation test measures the settlement caused by applying an increased load to a soil.
Consolidation measures the amount a soil will compress or decompress when a load is applied.
Consolidation can be conducted dry or saturated, or dry then saturated to measure heave.
Readings
USACE EM_1110-2-1906 Appendix VIII [3]
ASTM D2435/D2435M-11 [19]
Materials
Sieve nest
Sieve brushes
Tamper
Consolidation device
Displacement indicator
Caliper
Drying oven
Moisture tins
Procedure
A soil sample finer than the #40 sieve will be used. Determine the initial moisture content of
your sample using a representative quantity. Obtain the mass of the remaining soil (Wd) which will be
placed in the consolidation device. The soil will be remolded into the apparatus. The sample must be at
least 0.8 inches tall and no taller than 1.0 inches. Place the large porous disc below the mold in the
sample carriage. Place your sample soil within the mold and use a tamper to gently compact the soil,
allow the weight of the tamper to compact the soil and do not apply additional force to the sample.
Determine the initial height of the sample (H1). Measure the diameter of the sample cell and determine
the area (A). Calculate initial volume (Vi). Place the small porous disc on top of your sample with the
grove facing up. Place the brass loading head on the small porous stone. Center the loading yoke screw
onto the loading head and gently adjust until the loading arm is level, secure the loading yoke in place.
Saturate your sample by adding water to the carriage and waiting for the air to stop bubbling. Move
your dial indicator in place allowing for displacement in both directions, zero your indicator. Add 1 kg to
the loading arm and allow 5 minutes of pre-consolidation. At the end of the pre-consolidation period
add a load of 4 kg for 20 minutes, 8 kg for 20 minutes and 16 kg for 20 minutes. Each new load
application is referred to as a new stage in loading. Do not remove the weight between stages. Record
the time deformation readings in Table 13-1 below.
45. Table 13-1: Time vs. Deformation table.
Time
(minutes)
Deformation,
(d), (4 kg)
Time
(minutes)
Deformation,
(d), (8 kg)
Time
(minutes)
Deformation,
(d), (16 kg)
0.1 0.1 0.1
0.25 0.25 0.25
0.5 0.5 0.5
1 1 1
2 2 2
4 4 4
8 8 8
20 20 20
Plot these data on a deformation vs. Log of time curve and deformation vs. square root of time curve.
Also plot Strain vs. Stress. The volume of the solids (Vs) can be determined using Equation 13-1 below.
Equation 13-1: Volume of Solids.
𝑉𝑠 =
𝑊𝑑
𝐺𝑠 𝜌 𝑤
Wd= Dry mass of soil
Gs= Specific Gravity of solids
w= density of water
The effective height (He) can now be determined using Equation 13-2 below.
Equation 13-2: Effective height.
𝐻𝑒 =
𝑉𝑠
𝐴
The Effective Height is the height of the solids. The void ratio can now be determined using Equation 13-
3 below.
Equation 13-3: Void ratio.
𝑒 𝑛 =
𝐻 𝑛 − 𝐻𝑒
𝐻𝑒
en= Void ratio at nth
time interval
Hn= Height at nth
time interval
The data can be summarized using the previous equations and recorded in Table 13-2 below.
46. Table 13-2: Void Ratio and Strain information [16].
Applied Load
(kPA)
Stage
Deformation
(df), (mm)
Corrected
Deformation
H, (mm)
Strain (), (%) Final Stage
Height (Hf)
Void Ratio
df: the change in height for this stage of loading
H: total change in height for sample
The deformation, d50, which is the 50% change in height for the stage of consolidation. At this level of
deformation determine the values in Table 13-3 below.
Table 13-3: Coefficient of Consolidation, cv, data.
d50, (mm) 50, (%) H50, (mm) e50 t50 or t90,
(sec)
cv,
(mm2
/sec)
H50: Height of Sample at 50% deformation of stage.
To compute the coefficient of consolidation, cv, we can use Equation 13-4 below.
Equation 13-4: Coefficient of consolidation, cv.
𝑐 𝑣 =
𝑇𝐻 𝐷50
2
𝑡
Where:
T= 0.197 when using the log time plot or 0.848 when using the square root of time plot.
𝐻 𝐷50
= Half the specimen height for a double drained device [30].
t= time of consolidation. t50 for log of time plot and t90 for square root of time plot.
Assignment
Flat Foundations Inc. (FFI) has hired you to determine the time deformation curves in log of time
and in the square root of time, strain vs. stress and the coefficient of consolidation (cv) of a soil from
Swampland U.S.A. FFI also wants you to clarify Terzaghi’s Theory of Consolidation and why it is
important for them to consider this in their designs.
47. 14. Proctor Compaction
This lab will take most of the designated class time if all instructions are followed as stated. Soils
are compacted to achieve desirable engineering properties such as shear strength, compressibility or
permeability [17]. Foundations, dams and landfill liners are some typical projects where compaction is
utilized.
Readings
USACE EM_1110-2-1906 Appendix VI [3]
ASTM D698-91 [17]
Materials
Standard Proctor Hammer
4 inch Mold (Volume = 1/30 ft3
)
6 moisture cans
Large capacity balance (kg)
Small capacity balance (g)
Sieves (#4, Pan and Lid)
Straight edge
Mixing Pan
Large Spoon
Graduated cylinder (250 mL)
Sample extraction device
Procedure
Obtain approximately 3 kg of oven dried soil finer than the #4 sieve. Take an initial sample for moisture
content of raw soil. Add approximately 3% moisture content to the entire 3 kg of soil obtained. Weigh
the mold and base plate to the nearest gram (W1). Attach the collar and fasten the screws. Place the
assembled mold on the floor. Fill and compact the soil into the mold in three uniform layers using 25
evenly dispersed blows from the Standard Proctor Hammer. When the soil is compacted by three layers
to a level above the collar, remove the collar and use a straight edge to trim the soil flush with the top of
the mold. Weigh the mold and the soil (W2), divide by the volume of the mold to obtain the unit weight
(γ). Remove the mold from the base plate and remove the sample with the sample extractor. Be sure
the mold is placed in the center of the extractor or the device will break. Request help if uncertain.
After the soil has been removed from the mold obtain a representative sample and determine the
moisture content. Return the remainder of your soil to your mixing pan. Repeat the process at least 4
more times or until the unit weight decreases adding 3% moisture content to each additional trial. Using
Equation 14-1 below, we can determine the unit weight of each sample.
Equation 14-1: Unit weight.
𝛾 =
𝑊2 − 𝑊1
𝑉
Using Equation 14-2 below, we can determine the dry unit weight (γd).
Equation 14-2: Dry Unit weight.
𝛾 𝑑 =
𝛾
1 + 𝜔
48. ω= moisture content
Using values consistent with the range of data establish the saturation curves for our soil. Equation 14-3
below determines ω for the degree of saturation (S) at 80% and 100%.
Equation 14-3: Moisture content for Degree of Saturation.
𝜔 = 𝑆 (
𝛾 𝑤
𝛾 𝑑
−
1
𝐺𝑠
) × 100
γw= Unit weight of water
Gs= specific gravity of the soil (assume 2.4)
Graph your resulting data.
Assignment
Choose an engineering project such as one of the projects mentioned in the introduction. Feel free to
choose any other topic not mentioned where compaction is applied. Discuss the relative compaction
required for your project and what properties of the soil are important for this project. Also, determine
the relative compaction necessary for your project and at what dry unit weight this is achieved.
49. 15. Field Density
Field density testing is conducted to verify the soils on a project site will have the desired
properties for the type of project being constructed. There are destructive and non-destructive methods
for testing field density. The Sand Cone Method is one method for testing field density.
Readings
ASTM D1556-90 [18]
Materials
Sand Cone Device
Sand Cone Base Plate
Metal funnel
Small Excavation tool
Sand (Gs=2.65)
Aluminum dish
Balance beam and weights
Pocket Torvane Device
Pocket Penetrometer
Procedure
Ensure your device is working as intended and is properly fit to the base plate. Fill the sand cone
device with the required sand and obtain the initial weight (WSCi). Weigh the evaporating dish (Wevap).
Determine your sampling location. Place the base plate over the sampling site. Dig your sampling hole
approximately 1-1.5 inches deep and 2-3 inches in diameter. Collect all soil removed from hole,
including loosened fragments, in the evaporating dish. Carefully place the sand cone device into the
base plate. Open the valve and allow the sand to fill the hole, base plate and cone. After the sand stops
flowing into the cone the valve can be closed and the final weight of the sand cone device can be
obtained (WSCf). Determine the weight of the soil removed from the test hole (Ws). Now we can
determine the volume of the hole (Vh) using Equation 15-1 below.
Equation 15-1: Sand Cone Hole Calculation.
𝑉ℎ = (
𝑊𝑆𝐶𝑖 − 𝑊𝑆𝐶𝑓
𝛾𝑠𝑎𝑛𝑑
) − 𝑉𝑐
Vc= Volume of the cone (0.0344 ft3
)
The wet unit weight (γ) can now be determined using Equation 15-2 below.
Equation 15-2: Unit Weight.
𝛾 =
𝑊𝑠
𝑉ℎ
The dry unit weight can be calculated using Equation 14-2 from the Standard Proctor Compaction
assignment. Moisture content will be determined using the Speedy Moisture Tester. Follow the
instructions provided with the Speedy Moisture Tester.
In addition, you will also determine the Shear stress of the surface soil using a Pocket Torvane
device. The unconfined compressive strength will also need to be determined using the Pocket
Penetrometer.
50. Assignment
Your company has been hired to verify the compaction of fill material. The design unit weight
was 2,000 kg/m3
. Does the soil meet the required level of compaction? What is your recommendation to
your client? In addition to this experiment, discuss the other methods of testing field density both
destructive testing and non-destructive testing.
51. 16. Unconfined Compression
Many projects have different material characteristic requirements which need to be considered.
Every project will require a separate analysis of what characteristics will need to be determined and
what sorts of experiments are available to determine them. One such characteristic of soils sometimes
used to classifying a soil is the Undrained Shear Strength (Su
c
).
Readings
USACE EM_1110-2-1906 Appendix XI [3]
ASTM D2166 [19]
Materials
Harvard compaction device
Compression device
Evaporating dish
Spatula
Squirt bottle
Metal pan
Clayey Soil
Procedure
Obtain approximately 500 grams of soil finer than the #40 sieve. Add 10% moisture content to your
sample then use the Harvard Compaction Device to form your sample. Add and compress soil in layers.
Before adding a new layer use the spatula to rough up the surface of the old layer, this will ensure a
cohesive sample. Measure the Diameter (Di) and Height (Hi) of the sample along 3 separate axis. If the
sample is not symmetrical reform the sample in the compaction device. Place your sample on the
compression device. Close the gaps between the loading platforms and your sample without loading
your sample. Zero the proving ring gage and the strain gage. Begin loading your sample at a steady rate
and record the gage data at every whole number indicated on the gage without pausing the loading.
Continue loading your sample until there are obvious cracks, failure or a decrease in loading force
(which indicates failure). Obtain a few more data points to ensure a complete data set. Use Table 16-1
to record your data.
52. Table 16-1: Unconfined compression worksheet.
Strain gage
(ΔH)
Total Strain (ε) Proving ring
gage reading
Normal load
(Pn)
Corrected area
(Ac)
Unconfined
compressive
strength (qu)
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.13
0.14
0.15
0.16
0.17
0.18
0.19
0.20
Total Strain (ε) can be calculated for each row using Equation 16-1 below.
Equation 16-1: Strain.
𝜀 =
∆𝐻
𝐻𝑖
ΔH=Change in height of specimen.
The calibration factor can be found on the proving ring calibration sheet provided by the manufacturer.
The corrected area (Ac) can be calculated using Equation 16-2 below.
Equation 16-2: Corrected Area.
𝐴 𝑐 =
𝐴𝑖
1 − 𝜀
Ai=initial area of sample.
The Unconfined compressive strength (qu) of the sample, also commonly known as the stress applied,
can be calculated using Equation 16-3 below.
53. Equation 16-3: Unconfined Compressive Strength.
𝑞 𝑢 =
𝑃𝑛
𝐴 𝑛
An= corrected area at nth strain.
The Undrained shear strength (Su) can be calculated using Equation 16-4 below.
Equation 16-4: Undrained Shear Strength.
𝑆 𝑢 =
𝑞 𝑢
2
The normal load (Pn) can be determined using the Proving Ring Utility Chart. Figure 16-1 below shows an
example of a proving ring chart.
Figure 16-1: Proving Ring Chart Sample.
Proving Ring Utility Charts are calibration charts for specific proving rings. You will need to verify the
serial number of the proving ring and locate the associated chart. The charts provide two ways to
determine the force applied. The first way is to use the equations provided at the top of the chart.
Proving rings with one metal ring will only have one equation. As shown in Figure 16-1, some proving
rings include 2 metal rings and therefor have two equations. The second equation is used when you pass
the divisions on the dial indicator known as the Intersection Point. Force can also be determined directly
from the included tables. For division 73, the force is read as 24 lbs. For division 125, the force is read as
40 lbs.
Assignment
What is the unconfined compressive strength at failure, undrained shear strength at failure? Provide all
supporting graphs, tables and figures at failure to back up your data, be sure to provide Mohr’s circle.
Discuss how undrained shear strength applies to slope stability. In addition to Unconfined Compression
we will be conducting Field Identification of Soils using USCS Field Classification method provided in this
54. text. Compare the effectiveness of Field Classification to the Dry sieve analysis and Wet sieve analysis
conducted in previous assignments.
55. 17. Triaxial Compression: Unconsolidated Undrained
There are several different test which could be conducted using the Triflex system. The
consolidated undrained test (CU), consolidated drained test (CD) and unconsolidated undrained (UU).
The UU test is the simplest and fastest test and we will be conducting this test in class as an introduction
to the Triflex system. The system described in this method is developed by ELE International, there are
many other manufacturers and providers of similar equipment.
Readings
USACE EM 111-2-1906 Appendix X [3]
ASTM D2850 [20]
Materials
Tri-flex 2 Master Control Panel
Digital Tritest
Rubber membrane (70mm)
Porous stones
Rubber seals
Compaction mold
Modified Compaction hammer
Soil trimmer
Knife
Wire trimming saw
Large metal tray
250 mL graduated cylinder
Mortar and pestle
Large evaporating dish
Mixing tool
Sample extractor
Large pan
Sieves (#4, #10, #40, Pan, Lid)
Membrane stretching device and vacuum hose
4.5 kg of clayey soil
Procedure
There are multiple types of test which can be conducted using the Triflex system. Each test allows you to
gather different types of data. We will be conducting the UU test which will give us the principal stress
difference (). We will be taking multiple steps to prepare our samples, prepare the Triflex machine
and disassemble and clean up the Triflex machine. We must first mold our sample.
Clayey sample molding
We must initially prepare our soil by collecting approximately 4.5 kg of soil finer than the #40
sieve. 8% moisture content is then added to the sample and mixed thoroughly. Once the sample has a
consistent moisture content it will be added to the compaction mold and compacted in evenly sized
layers. Be sure to rough up the surface of the freshly compacted layer before adding more soil to ensure
binding of the layers. Once the sample has been molded it can be removed using the sample extractor.
Be sure to align the mold and the sample extractor as to not damage the device or sample. Once the
sample is removed, place it in the trimming device and carefully cut the sample down to the appropriate
56. size. When the sample has been trimmed to the appropriate size measure the length (L) and diameter
(D) at 120 degrees intervals around the sample and calculate the average. Use Table 17-1 below to
record your findings.
Table 17-1: Sample dimensions table.
Sample dimensions
Length 1: L1
Length 2: L2
Length 3: L3
Average Length:
𝑳 𝟏+𝑳 𝟐+𝑳 𝟑
𝟑
Area 1: A1
Area 2: A2
Area 3: A3
Average Area:
𝑨 𝟏+𝑨 𝟐+𝑨 𝟑
3
Table 17-1 will help determine the initial dimension of the sample. Place 2 rubber seals on the
membrane stretcher one above and one below the vacuum nozzle. Insert the rubber membrane into the
membrane stretcher and fold the edges over the membrane stretcher. Making sure there are no
wrinkles in the membrane roll the seals over the membrane and apply a vacuum. Place a porous stone
on the base adaptor within the Triflex cell. Place the sample on top of the porous stone and slide the
membrane stretcher over the sample. Carefully slide the membrane over the base adaptor and roll the
rubber seal into the grove on the base adaptor ensuring a waterproof seal. Now place a porous stone on
top of the sample and place the upper adaptor on top of the porous stone. Carefully place the rubber
membrane around the upper adaptor and roll the rubber seal into the grove ensuring the waterproof
seal. Carefully remove the membrane stretcher and attach the upper adaptor hoses to the baseplate.
These screws only need to be finger tight. Apply vacuum grease to the top and bottom edges of the
Triflex testing cell, ensure the large rubber seal is in place on the base, and carefully place the testing
cell over the sample. Taking the cell head, ensure the large rubber seal is in place, carefully place the cell
head on the testing cell. Make sure the rubber seal is placed correctly. The loading piston should be
placed within the notch on top of the upper adaptor on top of the sample. Install the tie rods with the
bolt placed in the baseplate grove. Tighten the tie rods evenly and finger tight. Turn on the Digital Tritest
and raise the base of the Triflex so that the load piston is aligned to the load ring, but no pressure should
be applied. Install the strain gage onto the load ring.
Prepare Triflex system
Turn on the Triflex 2 Master Control Panel. Wait for the display to stabilize then hit the tare
button. Turn on the vacuum supply, the gage on the front panel indicates the available vacuum. Turn on
the air supply, adjust the Master Regulator to your desired pressure. Never exceed 150 psi. Turn on
water supply slowly. Figure 17-1 below show the layout of the triflex control panel.
57. Figure 17-1: Triflex control panel nomenclature and layout.
Turn the De-Airing switch to fill. When the water is 1” from the top of the De-Aired water tank
turn the switch to Vent. Turn the De-Airing switch to Vacuum to remove the air from the tank (10-15
minutes). Refill the De-Aired water tank as necessary. Close all valves on the base plate of the test cell.
Turn the De-Airing switch to Pressure. Set the burette input switch to Vent. Turn Annulus switch to
open. Slowly turn the switch below the annulus to the fill position and raise the water level to the
desired position. Do Not Over fill the Annulus and flood the burette. Set bottom annulus switch to Cell
Operate. Turn the Annulus input switches to vacuum to de-air. The system is considered de-aired when
no more bubbles are observed rising from the system. The annulus is considered de-aired even when
bubbles remain on the walls of the annulus. Return input switches back to vent when complete.
Unconsolidated Undrained procedure
Connect the Lateral hose from the test cell to the quick release connecter marked Water.
Connect the drain line to the vent quick connector on the head of the test cell and place the hose to
drain in the sink. Turn the Lateral knob open and allow the test cell to fill with water. When water starts
to drain from the vent valve close the lateral switch on the base plate of the cell.
Disconnect the vent valve hose. Connect the Lateral hose to the annulus cell quick connect at
the bottom of the control panel. Check the bottom annulus switch is on Cell Operate. Set the annulus
switch to open (should already be open). Turn the Annulus switch towards Pressure. Adjust the Master
Regulator to a pressure between 10-30 psi. Turn the display switch for the first annulus to Display
Pressure and the other two switches set to Cancel Display. Slowly open the lateral switch at the bottom
of the base plate. Record the pressure displayed in red, this is confining pressure (3). Enter a rate of
58. displacement less than 1.11 mm/min when taking manual data. Using the Digital Tritest raise the
platform using the Run function until the sample buckles, bulges or the dial indicator decreases loading.
Using Table 17-2 below record the proving ring dial readings at every 10th
reading on the strain
indicator.
60. In Table 17-2, Column 2, the specimen deformation is determined by multiplying the strain dial reading
by the dial conversion factor found on the face of the dial. Vertical strain can then be calculated using
the original sample length (L0). The load applied can by calculated using the Proving Ring Calibration
Chart. Determine the moisture content and degree of saturation.
Disassembling the Triflex
The test cell needs to be drained first. Disconnect the Lateral hose from the Master Control
Panel and place in the sink. Next attach a quick connect hose to the Air output on the Master control
panel and connect the other end to the Vent valve on top of the test cell. Open the Lateral hose valve
and use the master regulator to apply pressure to the test cell. Water should now be draining out of the
test cell. During this time you can press the down double arrow once and the platform will begin
lowering to the datum, once the platform reaches the datum it will automatically stop. To drain the
Annulus and Burettes you will need to set all bottom valves to drain. Open the Annulus switches. Set the
upper Annulus valves to pressure. When the Annulus and burettes are empty set the upper valves to
vent and close the annulus switches. When the test cell is empty turn off the master regulator and then
turn off the master control panel. Disconnect the air hose from the vent on top of the test cell, close the
lateral valve and unscrew the lateral hose. Completely disconnect the hoses from the front and gently
roll them up and store them under the master control panel. You can now unscrew the test cell
retaining bolts and place them in front of the Digital Tritest. Once all three retaining bolts have been
removed, you can carefully lift off the head plate and place it in front of the master control panel, be
sure to keep the rubber seal with the head plate. The test cell can now be removed from the baseplate.
Carefully lift and take the baseplate to a large pan. Unscrew the upper adaptor hoses from the base
plate and carefully remove from the sample assembly. Carefully remove the rubber seals and the porous
stones. The rubber membrane and soil may be disposed of in a waste container. Rinse the porous stones
and rubber seals and place in an evaporating dish and soak in water. Wash the base plate and dry, then
return base plate to the Triflex platform.
Assignment
Provide a graph of Principle Stress Difference to Axial Strain and report the peak Principle Stress
Difference. Create and report a Mohr’s circle. Report the Undrained Shear Strength (Su). Discuss when it
is appropriate to conduct Unconsolidated-Undrained testing versus the other tests using the triaxial
compression device. Discuss when the other tests would be appropriate to be used and what data you
would be able to obtain from them.
61. 18. Direct Shear
The data obtained from a direct shear test can also be obtained using triaxial compression.
Using the direct shear machine can obtain the data slightly faster. You will wait for your instructor to
show you how to use the Direct Shear unit and DAQ. Any failure, over sight, or deviation from the
instructions will result in broken equipment.
Readings
USACE EM_1110-2-1906 Appendix IX [3]
ASTM D3080 [21]
Materials
Digital Shear Machine
GDU
Laptop with DS 7.2 software package
Shear Box Assembly (2.5” Dia.)
Weights
paintbrush
Calipers
Tamper
Fine sand
Procedure
You will use a fine sand for your experiment. Return soil to the original container after testing is
completed. 3 tests will be conducted on the soil using 2 kg, 4 kg and 8 kg. Check out the laptop with your
instructor. Plug in the Direct Shear machine, GDU and laptop to a power source. Plug in the USB adaptor
from the GDU into the port on the back and right side of the laptop. Turn on the power switch on the
back of the Digital Shear Machine, GDU and turn on the laptop. Login to the laptop using the username
and password provided with the laptop. You should be able to login to the laptop and access the
software using your User ID as well. Open the DS 7.2 software from the desktop or start menu. Allow the
software to conduct any and all systems checks. Reset logger if necessary, this will clear all data from the
GDU.
Remove the shear box assembly, shown in Figure 18-1 below.
62. Figure 18-1: Shear box seated in Carriage.
Figure 18-1 shows the shear box properly seated in the carriage. The displacement screws should easily
be seated into the swan neck groves. Figure 18-1 also shows the 4 separation screws inserted in the top
of the shear box. The 2 remaining holes in the shear box are for the 2 alignment screws. If the Shear box
assembly does not easily fit into the carriage or swan neck then the carriage may not have been
returned to its datum. Use the directional arrows on the Direct Shear machine keyboard to return the
carriage to its datum. Remove the alignment Screws, which should be in the empty holes in the Shear
box assembly in Figure 18-1. These screws should only be finger tight. Anything which requires a screw
driver to remove while working with the Direct Shear indicates an error was made and is a warning sign
that something is about to break. The separation screws need to be removed to ensure the Shear box
halves sit with no space between them. At this point you may insert the alignment screws and gently
tighten them with your fingers. The screws will not catch if the top half is facing the wrong direction.
Measure the depth of the shear box assembly and obtain the weight. Add fine sand to the shear
box assembly to a height approximately ½ to ¾ the height of the upper half, then determine the mass of
the soil added to the shear box assembly. Use the tamper to level the soil and determine the height of
the soil. Place the pressure pad on top of the fine sand. Before placing the shear box assembly into the
carriage make sure the carriage is attached to the loading shaft. Placing the shear box assembly may
require a gentle wiggle when sliding the shear box displacement screws into the swan neck. If the shear
box assembly does not easily fit into the carriage or swan neck then the carriage may not have been
returned to its datum. Once the shear box assembly has been placed inside the carriage and the upper
half screws are securely in the swan neck you can now tighten the locking screws on the carriage.
Making sure the loading lever is zeroed by adjusting the weighted screw on the back of the loading lever
until it is perfectly horizontal. Now place the loading yoke on the pressure pad and gently tighten in
place by lowering the bolt. Lock loading yoke in place by lowering the nut on the bolt. The alignment
screws can now be removed. Lower the separating screws at an even rate and separate the shear box
assembly halves the approximate distance equal or slightly greater than the largest diameter of the
sample particles, at this point you may use a screwdriver to carefully adjust the separation between the
shear assembly halves. Ensure the Horizontal and Vertical displacement transducers are gently secured
and placed on their respective displacement knobs.
63. You are now ready to start using the laptop. The DS 7.2 software should already be open and
finished with the systems check, (you need to be connected to the internet for the software to work).
Select New Test. Click on Direct Shear from list of test options. In the 3rd
column it should say available.
If not, return to main menu and select monitor test where you will delete active test data then return to
the new test menu. Select Direct Shear and click on Select Machine for test. You should now be at the
Sample Identification screen. All fields with an Asterisk must be filed in, other fields are optional. Click
OK when complete. You will now be taken to the Tests in Progress screen. Select Direct Shear from the
options and click OK. You will now receive a message to initialize your transducers, Reset all transducers.
You are now on the Test Monitoring screen. At the center top of your screen click on Start Test Stage,
this will open the Select a Stage from the list menu. Select Test Initialization. On this screen you will
input the soil weight, soil height and specimen condition. Also, you will input shear box area, and the
lever ratio of 10:1. Reset the vertical deformation gage. Now select OK. Return to Start Test Stage and
select Consolidation Stage. Ensure the Alignment Screws have been removed, your instructor must
verify this step. Weight on lever will be set to one of the three predetermined weights. Your initial
weight should be selected as to provide the ability to double the load for two additional tests. Input your
intended load multiplied by 10 in Weight on Hanger. Click Calculate stress. Prepare to place the initial
load on the load hanger and click Continue. Click on Start Test, this will initialize a 5 second countdown,
at the end of the countdown place weight on load hanger. You may select End Test Stage after the
consolidation appears to have stabilized. Select Start Test Stage. Select Shearing Stage. Input the
Maximum Recommended Rate of Shear Displacement also change the Minimum Recommended Logging
Rate to 0.05. The rate of displacement can be changed and observed from the Digital Tritest Machine in
the upper right hand corner of the display. Our rate of speed is 1.0 mm/min. Instructor must check that
all transducers are in place, carriage is properly attached, load is applied and alignment screws have
been removed. Reset the transducers. Click Continue. Start Test Countdown. At the end of the
countdown press Run on the Digital Shear Machine. You will now begin recording data, this process may
take 5 minutes. Never walk away from an operating machine. When there are no more readings press
Stop on the Direct Shear Machine. The Program will automatically finish and prompt you to stop the
Direct Shear Machine. Now click OK in the top right of the screen. Click Start Test Stage and select Final
Measurements and click OK. Input the wet and dry weight as the initial weight and input the room
temperature, click save data. Save data to a location on the Desktop, removable memory disk, or any
location easy to find. A screen will pop up and indicate the Final Stage is now complete. Press OK. Using
the arrow keys and watching the Horizontal displacement in the bottom left of your screen return to
carriage to the 0 datum. Your instructor must verify this step.
Now unload the load hanger. Clear the vertical and horizontal displacement transducers from
their respective loading platforms. Remove weights from loading hanger. Use your fingers to remove the
loading yoke, if the loading yoke cannot be unscrewed by your fingers you have not zeroed the
horizontal transducer or you have not removed the weights from the loading hanger.
Repeat the test 2 more times with double the weight on the loading hanger for each subsequent test.
You will now return to the Main Panel screen. Click on Analysis & Reports. Select Browse directory.
Select your folder. In the Raw Data Files options select your file and click on Analyse Test. Select Save
Data. You will now see your peak strength.
Minimize the DS 7.2 software. Open MS Excel and go to File, then Open, then Computer, and select
Browse. Open the files from the location where you chose to save or find your data at the location
automatically chosen by the software as follows. Go to Windows 8.1 (C:). Program Files (x86). DS 7.2
Application. Open Text Files folder. Open Raw Completed Tests folder. Open folder with your test
64. number. Open Shear Strength… folder, select your sample number and search “All Files (*.*)”. You can
now select the file ending in “.tab” and click Open. Save file to thumb drive or email data file to your
team. You will download all three files of the tests you completed today and conduct the appropriate
calculations.
Plot the resulting data as shown in Figure 18-1 below.
Figure 18-2: Shear Stress to Horizontal displacement data.
Figure 18-2 shows how some data will look when plotting shear stress to horizontal displacement. Some
data will show some elasticity by displaying what looks like steps. When the curves do not show an
effective peak and decrease in shear stress when failure occurs. Peak stress can be reported as the
maximum shear stress achieved. This interpretation will provide conservative results. Figure 18-3 below
plots the peak shear stress from each test to their respective normal stress.
Figure 18-3: Shear Stress to Normal Stress data.
65. The Angle of Friction and Cohesion can be determined from Figure 18-3. The Angle of Friction is the
angle of the best fit line with respect to the normal stress axis. Cohesion can be reported as the
intercept of the Shear Stress axis. A conservative interpretation and for granular materials, cohesion is
effectively 0.
Assignment
You will need to report the peak shear strength, effective cohesion and the effective friction
angle. Include your graph and Mohr’s circles. Discuss the applications of direct shear results.
66. 19. pH and Point of Zero Charge
The pH of soils and the Point of Zero Charge (PZC) influences the sorption capacity of soils and
will affect the mobility and transport of materials through the environment. At pH values greater than
the PZC the surface of a material is negatively charged and we can anticipate the reaction of these
surfaces with positively charged contaminants [31]. PZC can also be used to predict the sorption capacity
of treatment media for toxic metals [31]. There are multiple methods used to determine PZC, the
method described here is a Potentiometric Mass Titration (PMT).
Readings
Determination of sorbent point zero charge: usefulness in sorption studies [31]
Materials
Oven dried sample (0.1 g)
Ring stand and clamp
Burette (50 mL)
Magnetic stir plate
Magnetic stir bar
Erlenmeyer flask (250 mL)
DI water
pH meter
Scale
0.1 M HNO3 (titrant), ~20 mL per team
1 M KOH (buffer), ~ 10 mL per class
Absorption pads
Procedure
Place 0.1 g of sample material in the Erlenmeyer flask and add in 20 mL of DI water. Use the
magnetic stir plate to mix solution. Insert pH probe and determine the initial pH of the solution. Add one
drop of KOH solution and let the pH stabilize. The starting pH of the solution should be near pH 12.
Adjust solution accordingly. The burette should be filled with 20 mL of HNO3. While stirring the sample,
and taking continuous pH readings, slowly add drops of HNO3 until pH < 2. Record your pH values and
mL of titrant added in Table 24-1 below.
Table 19-1: Point of zero Charge work sheet.
Point of Zero Charge
Blank Sample:
pH mL Titrant: pH mL Titrant:
67. Repeat all steps for the titration on a sample of DI water with no sample for your Blank. Plot the data
from Table 19-1 on a single graph. The point of intersection is determined to be the Point of Zero
charge.
Assignment
Compare your PZC for determined in class for Kaolin with values from literature. Discuss the
method and application for PZC. Use the recommended reading as one source and conduct a literature
review to thoroughly discuss this characteristic of materials. Use a minimum of 5 additional sources. Be
sure to discuss how PZC can be used in engineering design.
68. 20. Metals Analysis through Acid Digestion
Digestion is the process of using acids to dissociate materials from each other to determine
metal content. The digestion process breaks the organo-metal bonds and frees the ions for analysis [32].
There are many types of analysis which may require some form of sample preparation which includes
digestion. This procedure will take 2 lab periods. This method uses spectrophotometry and limits the
analysis to one species at a time.
Readings
EPA Mild Digestion [32]
Mixing Solutions [33]
Aluminum Analysis [34]
Materials
Digestion
Magnetic stir and heat plates
pH meter
Pipettes
Disposable pipettes
Pipette bulb
Filter flask
Filter funnel
Filters (0.47 mm)
125 mL Erlenmeyer flask
100 mL Volumetric flask
5 mL concentrated HNO3 per liter of sample
5 mL 1:1 HCl per 100 mL sample
5.0 N NaOH
DI water
Aluminum Method
50 mL Graduated Cylinder
50 mL Volumetric flask w/ glass stopper
DR3000 Spectrophotometer
25 mL Sample cells (Cuvettes) or Test tubes
Ascorbic Acid Powder Pillow
AluVer 3 Aluminum Reagent Powder Pillow
Bleaching 3 Reagent Powder Pillow
DI water
Serial Dilution
Standard size test tube
Disposable pipette
10 mL pipette
Pipette bulb
69. Procedure
This method requires a sample size of 100 mL. Prepare your sample by adding a concentration
of 1 gram of soil to Liter of DI water. Add 5 mL of Nitric acid per 1 L of sample. This may have already
been completed by your instructor. Keep sample well mixed until ready for use. Obtain 100 mL of
prepared sample, and 100 mL of DI water. The 100 mL of DI water is your sample blank, and must
receive the same treatment as your sample. Add 5 mL 1:1 HCL acid to each sample. Heat sample on a
hot plate until the sample is reduced to 20 mL. If sample has not reduced sufficiently after 1.5 hrs,
proceed to the next step, and indicate the deviation from the standard methods in your report. Do not
boil your sample. Use the filter funnel and filter paper to remove the suspended solids from your
sample. Make sure not to dilute your sample in this process. Transfer the filtered liquid into a 125 mL
Erlenmeyer flask. Place a stir bar into the flask with your sample. Place the Erlenmeyer flask onto the stir
plate. Place the pH probe into your sample. Carefully use a disposable pipette to adjust the pH to 4 by
adding one drop of 5 N NaOH at a time. Remember on the far ends of the pH curve it takes more
solution to make a small impact on pH, while in the middle of the pH curve a small amount of solution
may have a dramatic effect. It will be very easy to overshoot pH 4. Transfer sample to 100 mL flask and
dilute sample to 100 mL [32].
Using the DR3000 Spectrophotometer [34], turn on the DR3000 (power button is on
back of machine). The following program is for Method 8012 Aluminum 0.0-1.0 mg/L. Enter 2 STORED
PROGRAM. The STORED PROGRAM light will come on and display 522.0. The SET WAVELENGTH and
ZERO lights will flash. Rotate the wavelength selector to 522 nm. This selector is located on the front,
right of the DR3000. Press CLEAR. The SET WAVELENGTH light will turn off and the display will show 0.
The ZERO light will continue to flash until the instrument is zeroed. Add 50 mL of sample to a volumetric
flask for mixing. Add contents of Ascorbic Acid Powder Pillow, and place stopper on flask. Invert flask
multiple times to mix. Add the AluVer 3 Aluminum Reagent Powder Pillow to sample. Replace stopper
and mix thoroughly. Pour 25 mL of sample into graduated cylinder. Add the Bleaching 3 Reagent to one
of your samples and mix thoroughly. The Bleached sample is your reagent blank. Your samples should sit
for 15 minutes. Prepare a serial dilution of your sample based on what concentration you expect. You
will need multiple pipettes or clean your pipettes between each dilution to prevent contamination with
higher concentrations of sample. Prepare one regular sample, one sample diluted to 1:2, 1:5, and 1:10.
For dilution of 1:2, mix 1 part sample with 1 part DI water. For dilution of 1:5, mix 1 part sample with 4
parts DI water, etc. [33]. Place the DI water reagent blank into the cell holder and cover sample cell,
press ZERO CONC. The ZERO CONCENTRATION and AUTO UPDATE lights should turn on and the display
should read 0.000. Place DI water sample into the spectrophotometer and obtain the DI water
background concentration. Place the reagent blank into the cell holder and cover sample cell, press
ZERO CONC. The ZERO CONCENTRATION and AUTO UPDATE lights should turn on and the display should
read 0.000. Place samples into sample holder and cover, once the reading has stabilized record the
number displayed. This is your concentration in mg/L [34]. Use Equation 20-1 to convert the sample
reading to mass/mass units.
Equation 20-1: Mass conversion of liquid sample.
𝐶𝑠,𝑀𝑒𝑡𝑎𝑙 = 𝐶 𝑤
1
𝐶𝑠
Cs, Metal= Concentration of analyte in soil (mass/mass)
Cw= Concentration of analyte in solution (mass/volume)
Cs= Concentration of soil added to water (mass/volume)
70. Assignment
Make special not of any deviations we took from the standard methods and discuss the impact
these deviations would have on our sample quality. Discuss the errors associated with our sampling
procedure, including the possible errors associated with the equipment. Report our final sample
concentration in mg/kg. What are the concentration and exposure limits according to USEPA for
Aluminum? Does our sample meet these requirements? If presented with a known sample. Does the
sample match the typical mineral concentration?
71. 21. Appendix A: Classification Datasheet
Table 21-1: Classification Summary.
Company Technician: Client: Date:
Sample: Sample Description:
D10: D30: D60: Other:
Cu Cc PL: LL: PI:
Classification: AASHTO: USCS: Other:
Table 21-2: Particle Size Distribution Summary.
Sieve Analysis Hydrometer Analysis
Percent Finer Diameter (mm) Percent Finer Diameter (mm)
Figure 21-1: Example Particle Size Distribution Curve.
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