LESSON 3
PRACTICE EXERCISE
The following items will test your grasp of the material covered in this lesson. There is only one correct answer
for each item. When you complete the exercise, check your answer with the answer key that follows. If you
answer any item incorrectly, study again that part of the lesson that contains the portion involved.
1. What three soil parameters must be determined in order to describe the Atterberg limits of a soil?
2. True or False. An interlocking soil structure is characteristic of poorly graded soils.
3. If the average CI of a layer of soil before remolding was 74 and after remolding was 70, what is the RI of the
soil layer?
4. What USCS symbol should be assigned to a soil with the following characteristics?
The percent of material retained on a Number 200 sieve: 43 percent
The LL of material passing a Number 40 sieve: 70
The PL of material passing a Number 40 sieve: 30
5. True or False. The field sampling of soils for trafficability purposes ideally takes place under the average
natural condition for that soil.
6. The RCI of the critical layer for a single pass of a container express (CONEX), 6x6, 16-ton transporter over a
particular region is 68. The VCI for one pass of the transporter is 72. Will the underlying soil support the
passage of the specified vehicle?
7. What is the USCS symbol assigned to highly organic materials that may be identified by their distinctive
colors, odors, or fibrous textures?
8. The CI is a measure of the shear strength of a particular layer of soil in its _________________________
state.
9. What USCS symbol should be assigned to a soil with the following characteristics?
The percent of material retained on a Number 200 sieve: 92 percent
The percent of coarse material retained on a Number 4 sieve: 82 percent
The gap-graded coarse fraction
The LL of material passing a Number 40 sieve: 50
The PI of material passing a Number 40 sieve: 30
10. The difference in moisture content between the LL and the PL of a soil is called the
_____________________.
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EN5341
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