Department of Earth Science |Northeastern Illinois University

INTRODUCTION TO GEOTECHNICAL ENGINEERING
ESCI 340
Spring, 2007

Review for Exam #2 (March 15, 2007)                                                                                  Dr. Sanders

By the end of today's class, you should be able to do the following:

* (DELETED)  Solve weight-volume problems that ask you to use the values of some soil properties to calculate the values of others.

* Using index cards, construct  soil phase diagrams that represent the relative proportions of mineral, fluid, and gas phases of a soil.  Cut the index cards apart to separate the phases.  Please use the following color scheme:

 mass: green cards weight: blue cards volume: yellow cards F (HINT: what is the mass of the gas phase of a soil?) F (HINT: what is the weight of the gas phase of a soil?) You will need two volume cards!

* Using a poster sheet  and a pen, arrange the cards to represent  the following properties of soil:

 q moisture content (w)   q porosity (n)         q degree of saturation (S)         q unit weight :                  s  unit weight of the soil sample (g)                 s  unit weight of water (gw)                 s  dry unit weight (gd) q density :                 s  density of the soil sample (r)                 s  dry density (rd)                 s  density of water (rw)        q specific gravity of solids (Gs)         q void ratio (e)        q relative density (Dr)

* (DELETED) Answer Practice Problems 4.1-4.3 (p. 113), 4.6 and 4.7 (p.114).

* (DELETED) Explain how to derive Equations 4.27, 4.29, and 4.30 in the textbook on p. 107.

* (DELETED) Homework for Thursday: as a group (groups assigned in class) show how to derive Equation 4.28.

Laboratory Determination and Analysis of Grain Size and Plasticity

Lab Methods

* Show how to perform the sieve test portion of a grain size distribution analysis (presentation by Maureen and Evelyn).

* Explain how to use the hydrometer method to determine the grain size distribution of the fine portion of a soil sample (presentation by Rob J and Rob B).

* Explain the use of the term "percent finer".

Analyzing the Results; Grain Size Distribution Graphs

* Looking at a grain size distribution graph, differentiate between sediment samples that are poorly graded and those that are well graded.

* Using a grain size distribution graph, read off the D10, D30, and D60, and calculate the coefficient of uniformity (Cu).

* Construct grain size distribution curves for the sample analyses distributed in class, and those
reported in Problem 4.12 on p. 124.

Fines and Plasticity

* Explain the meaning of the engineering term "fines" as it applies to grain size, and describe the difference between silt and clay.

* Explain the difference between soil in a liquid, solid, and semi-solid state.

* Explain what the Atterberg limits of a soil tell us.

* Show how to determine the liquid limit, plastic limit, and plasticity index of a soil sample in the laboratory.

Describing and Classifying Soils

* Use the ASTM Visual Manual procedure to investigate and describe the characteristics of a soil sample (presentation by Krys and Hossein).

* Use the USDA texture triangle to classify a soil sample.

* Use the USCS classification system to classify a soil on the basis of lab tests.  (Presentation by Jeff.)

* Use the AASHTO classification system to classify a soil sample.

Site Exploration and Characterization

* Describe the standard methods for characterizing a site in terms of its geotechnical aspects.  (Presentation by Matt and Dustin.)

Department of Earth Science | Northeastern Illinois University

© 2007 Laura L. Sanders.  Last updated March 8, 2007.