What is the primary function of retaining walls?

To stabilize hillsides and control erosion.

Which type of retaining wall is constructed primarily of dense, heavy materials like concrete and stone masonry?

Gravity walls.

Fill in the blank: A __________ retaining wall derives stability from its weight and typically has a trapezoidal section.

Semi Gravity Retaining Wall

True or False: Cantilever retaining walls are suitable for retaining backfill at heights greater than 7 meters without the need for additional support.

False. Cantilever retaining walls are suitable for moderate heights (4m-7m).

Riddle: I can hold back soil, I'm often shaped like an 'L' or inverted 'T', and I derive my strength from my own weight. What am I?

Cantilever retaining wall.

What are the two main types of flexible walls mentioned?

Sheet pile walls and diaphragm walls.

Fill in the blank: __________ walls are suitable for temporary structures where driving depth does not exceed 3 meters.

Timber sheet pile

Which type of sheet pile wall is held in place by anchors?

Anchored sheet pile walls.

True or False: Diaphragm walls require extensive dewatering during construction.

False. Diaphragm walls do not require construction dewatering.

What structure is formed by stacking wire cages filled with stone for riverbank stabilization?

Gabion walls.

Fill in the blank: The __________ theory assumes that there is no wall friction in the calculation of earth pressure.

Rankine's Earth Pressure

Riddle: I represent the pressure acting on a wall due to soil, typically found at a height of H/3. What am I?

Active earth pressure.

In the context of retaining walls, what does the term 'backfill' refer to?

The material being retained by the wall.

Which expression is used for calculating the coefficient of passive earth pressure?

Kp = (1 + sinΦ) / (1 - sinΦ).

True or False: The active earth pressure on a wall increases with depth in the case of cohesionless soils.

True.