Page 284 - Geotechnical Engineering Soil and Foundation Principles and Practice

Soil Consistency and Engineering Classification
Soil Consistency and Engineering Classification 279

12.20. Give four examples of borderline classifications in the Unified Classifica-
tion system and explain what each means.
The following problems are with reference to data in Table 7.5 of Chapter 7.
12.21. Classify soils No. 1, 2, and 3 in Table 7.5 according to the AASHTO and
Unified systems.
12.22. Classify soils No. 4, 5, and 6 in Table 7.5 according to the AASHTO
and Unified systems.
12.23. Classify soils No. 7, 8, and 9 in Table 7.5 according to the AASHTO and
Unified systems.
12.24. Classify soils No. 10, 11, and 12 in Table 7.5 according to the AASHTO
and Unified systems.
12.25. Which soil in each system is most susceptible to frost heave? What
characteristics contribute to this susceptibility?
12.26. Which soil in each system is most expansive? Which is moderately
expansive?
12.27. A loess soil changes from A-4 to A-6 to A-7-6 depending on distance from
the source. Predict the volume change properties including expansion and
collapsibility.
12.28. State the Denisov criterion for loess collapsibity. Does it take into account
the increase in density with depth?
12.29. Seasonal changes in moisture content of an expansive clay deposit
extend to a depth of 4 m (13 ft). Does that depth coincide with the
thickness of the active layer? Why (not)?
12.30. Why classify soils?

References and Further Reading

American Society for Testing and Materials. Annual Book of Standards. ASTM,
Philadelphia.
Chen, F. K. (1988). Foundations on Expansive Soils, 2nd ed. Elsievier, Amsterdam.
Grim, R. E. (1968). Clay Mineralogy. McGraw-Hill, New York.
Hallberg, G. (1977). ‘‘The Use of COLE Values for Soil Engineering Evaluation.’’ J. Soil
Sci. Soc. Amer. 41(4), 775–777.
Handy, R. L. (1973). ‘‘Collapsible Loess in Iowa.’’ Soil Sci. Soc. Amer. Proc. 37(2),
281–284.
Handy, R. L. (2002). ‘‘Geology, Soil Science, and the Other Expansive Clays.’’ Geotechnical
News 20(1), 40–45.
Katti, R. K., Katti, D. R., and Katti, A. R. (2005). Primer on Construction in Expansive
Black Cotton Soil Deposits with C.N.S.L. (1970 to 2005). Oxford & IBH Publishing
Co., New Delhi.
Skempton, A. W. (1953). ‘‘The Colloidal Activity of Clays.’’ Proc. 3rd Int. Conf. on Soil
Mech. and Fd. Engg. 1, 57.
U.S. Department of Interior Bureau of Reclamation (1974). Earth Manual, 2nd ed.
U.S. Government Printing Office, Washington, D.C.

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