# Civil Engineering - UPSC Civil Service Exam Questions - Discussion

Discussion Forum : UPSC Civil Service Exam Questions - Section 2 (Q.No. 1)

1.

A soil has a bulk density of 1.80 g/cm

^{3}at water content of 5%. If the void ratio remains constant, then its bulk density for a water content of 10% will beDiscussion:

14 comments Page 1 of 2.
Rushikesh patil said:
4 years ago

STEP 1. Y= 1.8/(1+0.05)

Y=1.71.

STEP 2. put y value in same formula,

1.71=x/(1+0.1),

X = 1.88.

(X is an unknown bulk density.)

Y=1.71.

STEP 2. put y value in same formula,

1.71=x/(1+0.1),

X = 1.88.

(X is an unknown bulk density.)

(5)

Pankaj Kalam said:
1 decade ago

Bulk density Yb.

Dry Density Yd.

water content w.

Yb = Yd(1+w).

1.80 = Yd (1+.05).

Yd = 1.8/1.05.

Yd = 1.71.

Yb = 1.71*(1+.1).

Yb = 1.88.

Dry Density Yd.

water content w.

Yb = Yd(1+w).

1.80 = Yd (1+.05).

Yd = 1.8/1.05.

Yd = 1.71.

Yb = 1.71*(1+.1).

Yb = 1.88.

(1)

Pradeep Thogiti said:
7 years ago

For bulk density formula, further simplification we get;

(y2)/(y1) = (1+w2)/(1+w1),

=> y2/1.80 = (1+0.1)/(1+.05),

=>y2= 1.88.

(y2)/(y1) = (1+w2)/(1+w1),

=> y2/1.80 = (1+0.1)/(1+.05),

=>y2= 1.88.

(3)

Nithin S said:
4 years ago

Theoretically, adding water dosen't change dry density.

Hence, Yd is constant.

Hence, Yd is constant.

(1)

Akshay Thakur said:
6 years ago

Option D is correct and the answer is 1.88 gm/cc.

(2)

Madhu said:
6 years ago

Please tell me how it is calculated?

Vel said:
3 years ago

I agree 1.88 is the correct answer.

(3)

Sinha said:
7 years ago

1.71*(1+.1).

Yb = 1.88. wrong.

Yb = 1.88. wrong.

Minnu Rajeev said:
5 years ago

Option D is the correct answer.

(3)

Ajay Kumar Yadav said:
1 year ago

Agree, A is the correct answer.

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