Geotechnical Engineering

DHARM

200 GEOTECHNICAL ENGINEERING

9. Schaffernak: Uberdie Stansicherheit durchlaessiger ges chuetterter Damme, Allgem, Bauzeitung,
   1917.


10. G.N. Smith: Essentials of Soil Mechanics for Civil and Mining Engineers, third edition Metric,
    Crosby Lockwood Staples, London, 1974.


11. M.G. Spangler: Soil Engineering, International Textbook Company, Scranton, USA, 1951.


12. D.W. Taylor: Fundamentals of Soil Mechanics, John Wiley & Sons, Inc., NY, 1948.

Questions and Problems

6.1 Write short notes on ‘Flow nets’. (S.V.U.—Four year B.Tech.—Apr., 1983)

6.2 (a) What are the principles of a flow net? What are its uses?

(b) Explain the phenomenon of ‘‘Piping’’. (S.V.U—B.Tech., (Part-Time)—May, 1983)

6.3 What are the salient characteristics of a flow net?

Describe a suitable procedure of drawing flow net. (S.V.U.—B.Tech., (Part-Time)—Sep., 1982)

6.4 Write short notes on: Critical hydraulic gradient, Phreatic line.

(S.V.U.—B.Tech., (Part-Time)—Apr., 1982)

6.5 Write short notes on : Quicksand conditions, Laplace system.

(S.V.U.—Four year B.Tech., —June, 1982)

6.6 Briefly discuss:

(i) Properties and utility of the flow net.

(ii) Seepage force

(iii) Electrical analogy method. (S.V.U.—B.Tech., (Part-Time)—Apr., 1982)

6.7 (a) Explain the meaning of the term ‘‘ Seepage pressure’’.

(b) Show how the effective pressure is altered when water is flowing through the soil vertically

downwards and vertically upwards. (S.V.U.—B.E., (R.R.)—Sep., 1978)

6.8 Stating the basic principles of flow nets describe the trial sketching method of obtaining a flow

net with particular reference to a homogeneous earth dam. (S.V.U.—B.E., (R.R.)—Nov., 1975)

6.9 (a) Define ‘‘Critical hydraulic gradient’’ and explain how ‘‘piping’ is produced.

(b) Explain the principle of drawing flow nets and derive the expression to calculate the amount

of flow of water in the case of a sheet pile wall with a head of water h on one side.

(S.V.U.—B.E., (R.R.)—May, 1970)

6.10 The hydraulic gradient for an upward flow of water through a sand mass is 0.90. If the specific

gravity of soil particles is 2.65 and the void ratio is 0.50. will quicksand conditions develop?

6.11 The foundation soil at the toe of a masonry dam has a porosity of 40% and the specific gravity of

grains is 2.70. To assure safety against piping, the specifications state that the upward gradient

must not exceed 25% of the gradient at which a quick condition occurs. What is the maximum

permissible upward gradient?

6.12 In a container filled with each of the following materials, at a porosity of 40%, determine the

upward gradient required to cause quick condition:

(a) lead shot with a specific gravity of 11.35;

(b) fibre beads with a specific gravity of 1.55;

(c) sand with a specific gravity 2.65.