ASBOG Engineering Geology 2

Question 1

Which index property is most directly used to assess the liquefaction potential of a sandy soil?

Accepted Answer

Relative density

Answer

Relative density (Dr) controls how loosely or densely sand is packed, which directly governs its susceptibility to liquefaction under cyclic loading.

Question 2

A rock mass with three mutually perpendicular joint sets has a maximum block volume defined by spacing S1, S2, and S3. What is the block volume?

Accepted Answer

S1 × S2 × S3

Answer

For three orthogonal joint sets, the intact block is a rectangular parallelepiped with volume equal to the product of the three spacings.

Question 3

Which geophysical method is best suited for detecting a buried paleochannel filled with saturated sand beneath a clay layer?

Accepted Answer

Electrical resistivity tomography

Answer

Electrical resistivity tomography (ERT) can differentiate between the conductive clay and the more resistive or differently resistive saturated sand in the paleochannel.

Question 4

During a slope stability analysis, a tension crack filled with water increases the driving force primarily by:

Accepted Answer

Adding hydrostatic pressure on the failure plane

Answer

Water in a tension crack exerts hydrostatic pressure directed into the slope, which increases the net driving force on the potential failure surface.

Question 5

The Standard Penetration Test (SPT) N-value correction for overburden stress is called the:

Accepted Answer

Overburden correction factor (CN)

Answer

The overburden correction factor CN adjusts raw SPT N-values to a reference effective stress of 1 atm so results from different depths can be compared.

ASBOG - Association of State Boards of Geology Practice Test

ASBOG - Association of State Boards of Geology Practice Test

ASBOG Engineering Geology 2