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# Seepage Analysis – Phreatic Line of an Earth Dam

1 - Question

What are the essentials, required to draw a flow net?

a) Top Flow and Phreatic line

b) Stream line

c) None of the mentioned

d) All of the mentioned

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Answer: aExplanation: In order to draw the flow net, it is first essential to find out the location and shape of the phreatic line and top flow line separating the saturated and unsaturated zones.

2 - Question

The phreatic line can be located by which of the following method?

a) Graphical method

b) Experimental method

c) Analytical method

d) All of the mentioned

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Answer: dExplanation: As suggested by casagrande, the phreatic line can be located by graphical, experimental and analytical methods.

3 - Question

Kozney’s top flow lines is called as ____________

a) Basic and Base parabola

b) Simple parabola

c) None of the mentioned

d) All of the mentioned

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Answer: aExplanation: Kozney’s solution for flow of water consists of a family of confocal parabola s representing the flow lines. Hence kozney’s top flow line is called the basic or base parabola.

4 - Question

For the water flowing above an impervious, infinite, horizontal plane. The net flow is given by ___________

a) Casagrande

b) Kozney

c) Forchheimer

d) Darcy

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Answer: aExplanation: In 1938, kozney analytically derived a flow net for the case of water flowing above an impervious, infinite, horizontal plane which at a certain place becomes permeable.

5 - Question

What is the line within a dam section, below which there are positive hydrostatic pressures?

a) Phreatic and Seepage line

b) Equipotential line

c) None of the mentioned

d) All of the mentioned

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Answer: aExplanation: The phreatic line or seepage line is the line within a dam section below which there are hydrostatic pressures in the dam. The hydrostatic pressure below on the phreatic line itself is atmospheric.

6 - Question

The flow lines and equipotential proposed by Kozney is in the shape of ____________

a) Hyperbola

b) Ellipse

c) Parabola

d) Circle

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Answer: cExplanation: According to flow net derived by Kozney, the flow lines and equipotential consist of the shape of parabola.

7 - Question

The analytical solution of schaffernak and Van Iterson gave result only for slopes, having __________

a) α>30°

b) α<30°

c) α>60°

d) α<60°

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Answer: bExplanation: The analytical solution of schaffernak and van iterson provided result, as long as slope is gentle i.e., α<30°. For steeper slopes, the deviation form correct values increases rapidly beyond tolerable limits.

8 - Question

What kind of method was suggested by Casagrande, for determining the phreatic line?

a) Experimental method

b) Analytical method

c) Graphical method

d) All of the mentioned

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Answer: cExplanation: Graphical method was used by Casagrande for the determination of the phreatic line using flow net.