CLARB Soils and Geology 2

Question 1

Which ASTM standard governs the Standard Proctor compaction test used to determine optimal moisture content for maximum dry density?

Accepted Answer

ASTM D698

Answer

ASTM D698 defines the Standard Proctor test using standard compaction energy; ASTM D1557 is the Modified Proctor test with higher compaction energy.

Question 2

Which soil condition presents the greatest risk for building foundations and hardscape due to volumetric changes with moisture fluctuations?

Accepted Answer

Expansive clay soils

Answer

Expansive clays (high in montmorillonite) swell significantly when wet and shrink when dry, causing differential movement that damages foundations and pavements.

Question 3

The angle of repose is a critical soil engineering property that most directly influences which landscape design consideration?

Accepted Answer

Slope stability and cut/fill grading design

Answer

The angle of repose defines the steepest angle at which loose soil remains stable; it directly dictates maximum allowable slope gradients for cut and fill sections.

Question 4

What does soil bearing capacity describe in the context of landscape construction?

Accepted Answer

The maximum load per unit area soil can support without failure or excessive settlement

Answer

Bearing capacity defines the maximum stress the soil can withstand before shearing or settling excessively, which is critical when designing structures, walls, and pavements.

Question 5

Liquefaction — where saturated soil temporarily loses strength and behaves like a liquid — is most commonly triggered by which event?

Accepted Answer

Seismic (earthquake) activity

Answer

Earthquakes generate rapid cyclic loading that increases pore water pressure in saturated, loose granular soils until effective stress drops to zero, causing liquefaction.

CLARB - Council of Landscape Architectural Registration Boards Practice Test

CLARB - Council of Landscape Architectural Registration Boards Practice Test

CLARB Soils and Geology 2