Active and Passive Pressure

Q. When a retaining wall moves away from the backfill, the pressure exerted on the wall is termed as

1. passive earth pressure
2. swelling pressure
3. pore pressure
4. active earth pressure

Q. The earth pressure for the design of bridge abutments is taken as

1. active thurst
2. passive thurst
3. thrust in at-rest condition
4. none of the above

Q. Cohesion in soil

1. decrease active pressure and increase passive resistance
2. decrease both active pressure and passive resistance
3. increase the active pressure and decrease the passive resistance
4. increase both active pressure and passive resistance

Q. No tension should develop at the base of the rectangular well foundation or at any horizontal section within the well. For no tension at the base, the resultant of $P_a$ (Total active thrust) and $W$ ( Weight of soil and well above the base) must pass through middle

1. half of the base
2. third of the base
3. quarter of the base
4. of the base

Q. Figure given below shows a smooth vertical gravity retaining wall with cohesionless soil backfill having an angle of internal friction $\varphi$. In the graphical representation of Rankine's active earth pressure for the retaining wall shown in figure, length OP represents

1. vertical stress at the base
2. vertical stress at a height H/3 from the base
3. lateral earth pressure at the base
4. lateral earth pressure at a height H/3 from the base

Q. For a sample of dry, cohesionless soil with friction angle $\varphi$, the failure plane will be inclined to the major principal plane by an angle equal to

1. $\varphi$
2. ${45}^{\circ }$
3. ${45}^{\circ }-\varphi /2$
4. ${45}^{\circ }+\varphi /2$

Q. Consider the following statements:

1. According to Terzaghi, the average angle of wall friction may be taken equal to two-thirds of the respective angle of internal friction.
2. Wall friction increases the active earth pressure and also decreases the passive earth resistance of the soil.
3. Wall friction decreases the active earth pressure and increases the passive earth resistance of the soil.

Which of the above statements is/are correct?

1. 1, 2 and 3
2. 1 and 2 only
3. 3 only
4. 1 and 3 only