Geotechnical Engineering

DHARM

110 GEOTECHNICAL ENGINEERING

References

1. A Casagrande: Classification and Identification of Soils, Transactions of ASCE, Vol. 113, 1948.


2. IS: 1498-1970 (First Revision) : Classification of Soils for General Engineering Purposes.


3. A.R. Jumikis: Soil Mechanics, D. Van Nostrand Co., Princeton, NJ, 1962.


4. D.W. Taylor: Fundamentals of Soil Mechanics, John Wiley & Sons Inc., NY, U.S.A., 1948.


5. The Unified Soil Classification System. Appendix B, Technical Memorandum No. 3-357, March
   1953, revised June, 1957. U.S. Army Engineer Waterways Experiment Station, Corps of Engi-
   neers, Vicksburg, Mississippi, U.S.A.


6. M. Whitney: Methods of the Mechanical Analysis of Soils, U.S. Department of Agriculture, Divi-
   sion of Agricultural Soils, Bulletin No. 4, Washington, D.C., Government Printing Office, 1896.

Questions and Problems

4.1 (a) Four soil samples collected from a borrow area, to form a low earth dam, are classified as

GW, CL, SC and SM. What is your inference?

(b) The following data relate to five soil samples.

LL (%) ... 25 45 50 60 80

PL (%) ... 15 23 25 35 36

Plot these on Casagrande’s A-line chart and classify the soils.

(S.V.U.—B.Tech. (Part-time)—May, 1983)

4.2 The following data refer to a sample of soil:

Percent passing 4.75 mm IS Sieve = 64

Percent passing 75-μ IS Sieve = 6

Uniformity Coefficient = 7.5

Coefficient of Curvature = 2.7

Plasticity index = 2.5

Classify the soil.

4.3 A certain soil has 99% by weight finer than 1 mm, 80% finer than 0.1 mm, 25% finer than 0.01

mm, 8% finer than 0.001 mm. Sketch the grain-size distribution curve and determine the per-

centage of sand, silt and clay fractions as per IS nomenclature. Determine Hazen’s effective size

and uniformity coefficient.

4.4 (a) Write a brief note on Textural classification.

(b) Sketch neatly the Casagrande’s plasticity chart indicating various aspects. How would you

use it in classifying the fine grained soils? Give a couple of examples. How would you differ-

entiate between organic and inorganic soils? (S.V.U.—B.Tech., (Part-Time)—Sept., 1982)

4.5 (a) Bring out the salient aspects of Indian Standard Classification System.

(b) Write a brief note on the Textural classification.

(c) How would you distinguish if a material is:

(i) GW or GP or GM or GC

(ii) SW or SP or SM or SC (S.V.U.—B. Tech., (Part-time)—April, 1982)