Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Discussion Forum : Soil Mechanics and Foundation Engineering - Section 1 (Q.No. 1)
1.
In a liquid limit test, the moisture content at 10 blows was 70% and that at 100 blows was 20%. The liquid limit of the soil, is
35%
50%
65%
none of these.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
123 comments Page 6 of 13.

Alekhya said:   8 years ago
Water content at 25 blows gives you the liquid limit.

Just interpolate the given values for 25 blows. You get the answer as 65.

Brijesh Singh Satyal said:   8 years ago
Flow index = -(W2-W1) / ln(N1/N2).

From the given data, it comes out to be 50.

Amit Kumar said:   8 years ago
Plot it on semilog graph and find water contentbfor 25 blow.

Madhur said:   8 years ago
Answer is B, why are you taking the difference between 100 and 10 values?

Bikashbiru said:   8 years ago
Yes, I agree @Ramesh.

Sasi said:   8 years ago
Why we say liquid limit at 25 blows? What is the reason?

Naresh said:   8 years ago
I think aprox 65 is correct.

Hatem Alhamaidi said:   8 years ago
Answer is:

LL = 61.7 % by interpolation.

Hemant maher said:   8 years ago
W1=10, W2=20, N1=70, N2=100.

So,
I = (w2-w1)/log(n2/n1).
I = 64.51= 65%.

Tomin Nyodu said:   8 years ago
@Hemant Mahar.

Method 1
I = (w1-w2) /log(n2/n1)
I= (70-20)/log(100/10)
I= 50

Hence, the ans is option (b)

Method 2
W1=70(10/25)^0.121=62.65
W2=20(100/25)^0.121=23.65

W1-W2=38.99 (Wrong)
Why? This is an empherical Formula and the value of the exponent is between 0.068 to 1.210.


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