Effect of Seepage Pressure on Effective Stress

Q. A soil mass under seepage has a downward flow of water. Which of the following statements are correct with regard to stresses at any point in the soil mass?
1. Effective stress is decreased by an amount equal to the seepage force
2. Effective stress is increased by an amount equal to the seepage force
3. Total stress will change
4. Total stress will be unaltered
Select the correct answer using the codes given below:

1. 1 and 3
2. 2and 3
3. 1 and 4
4. 2and 4

Q. A seepage flow condition is shown in the figure. The saturated unit weight of the soil ${\gamma }_{sat}=18kN/m^3$. Using unit weight of water, ${\gamma }_w=9.81kN/m^3$, the effective vertical stress (expressed in $kN/m^2$) on plane X-X is

1. 65.475

Q. Water flows in the upward direction in a tank through 2.5 m thick sand layer as shown in the figure. The void ratio and specific gravity of sand are 0.58 and 2.7, respectively. The sand is fully saturated. Unit weight of water is$10kN/m^3$.
The effective stress ( in kPa, round off to two decimal places) at point A, located 1 m above the base of tank, is .

1. 8.93

Q. A unit volume of a mass of saturated soil is subjected to horizontal seepage. The saturated unit wt. is $22kN/m^3$ and the hydraulic gradient is 0.3. The resultant body force on the soil mass is

1. 1.98 kN
2. 6.6 kN
3. 11.49 kN
4. 22.97 kN

Q. Match List-I (Flow type) with List-II (Flow characteristics) and select the correct answer using the codes given below the lists:
List-I
A. Transient flow
B. Turbulent flow
C. Steady-state flow
D. Laminar flow
List-II
1. Seepage flow is a function of time
2. Hydraulic gradient varies with square of velocity
3. Flow at low velocity
4. Governing equation in 2-D is

$k_x\frac{{\partial }^{2}h}{\partial x^2}+k_y\frac{{\partial }^{2}h}{\partial y^2}=0$

Codes:
A B C D

1. 1 2 4 3
2. 3 2 1 4
3. 1 2 3 4
4. 2 1 4 3