Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Discussion Forum : Soil Mechanics and Foundation Engineering - Section 1 (Q.No. 45)
45.
A coarse-grained soil has a voids ratio 0.75, and specific gravity as 2.75. The critical gradient at which quick sand condition occurs, is
0.25
0.50
0.75
1.00
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
21 comments Page 1 of 3.

Avshesh said:   7 years ago
Water is flowing in an upward direction through the structure of sand 5m thick under a total head difference of 3m. The sand has a specific gravity of 2.55 and voids ratio of 0.55. The factor of safety against quick condition would be?

Rahul said:   8 years ago
The hydraulic head that would produce a quick sand condition in a sand stratum of Thickness 1.5 m, specific gravity 2.67 and voids ratio 0.67 is equal to;

(a) 1.0 m
(b) 1.5 m
(c) 2.0 m
(d) 3.0 m

Please explain it with the answer.

MANOJ KUMAR VERMA said:   1 decade ago
Critical hydraulic gradient = (G-1)/(1+e).

= (2.75-1)/(1+0.75).

= 1.00.

Dinker said:   7 years ago
Icr(for flowing water) = 3/5 = . 6.

And;
Icr (for soil) = (G-1)/(1+e) = (2.55-1)/(1+.55) = 1.
F.o.s = 1/.6 = 1.66.

PIYUSH SINGH said:   1 decade ago
Hydraulic Gradient (Id) = (G-1)/(1+e).

= (2.75-1) / (1+0.75).

= 1.

Khan said:   6 years ago
What is the Relationship between porosity (n) and specific gravity (G) and critical hydraulic gradient (i)?

Ashok tastode said:   6 years ago
Ic = G-1/1+e=2.67-1/1+0.67 = 1.67/1.67.

Hydraulic gradient i = hydraulic length/head.

1= h/1.5m.
H=1.5m.

Ibraheem majeed said:   8 years ago
Head loss = hydraulic gradient * length or thickness.

Apply it you will get head loss as 1.5 @Rahul.

Anju said:   1 decade ago
Critical Hydraulic gradient = (G-1)/(1+e).

Where,

e - Void ratio.
G - Specific gravity of soil.

Laxman said:   1 decade ago
Already they said critical gradient for critical hydraulic gradient is 1. no need of calculation.


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