Rock Mechanics and Rock Engineering MCQs Questions & Answers | Geological Engineering

Uniaxial Compressive Strength (UCS) is the maximum axial compressive stress a rock specimen can withstand under uniaxial loading.It is a key parameter for evaluating rock strength.

The Brazilian test (indirect tensile test) is used to determine tensile strength by applying load diametrically on a disc-shaped rock specimen.

RMR system is a geomechanical classification system to assess the quality of a rock mass based on parameters like UCS, joint spacing, condition, etc.

Anisotropy means that the physical or mechanical properties of rock vary with direction.This affects strength and deformation behavior.

UCS is usually expressed in megapascals (MPa), where 1 MPa = 1 N/mm�.

In rock mass engineering, joint spacing and orientation are more critical than the strength of intact rock.

The correct answer is B: Evaluating weathering resistance.

Here's why:

The slake durability test is specifically designed to assess how well a rock can withstand repeated cycles of wetting and drying.
This simulates the weathering process that happens in nature.

Let's look at why the other options are incorrect:

A: Measuring compressive strength: Compressive strength is measured using a different test where a rock sample is crushed under pressure.
C: Determining porosity: Porosity (how much empty space is in a rock) is measured using other methods, such as water saturation or gas expansion techniques.
D: Measuring cohesion: Cohesion (how well the particles within a rock stick together) is related to shear strength and is generally measured using a shear test.

So, the slake durability test is all about seeing how a rock holds up to weathering!

In Mohr�s Circle, shear stress reaches a maximum at 45� to the principal stress axis, commonly associated with failure planes.

The Mohr-Coulomb criterion is widely used to predict failure in rocks based on cohesion and angle of internal friction.

GSI (Geological Strength Index) is a system to estimate rock mass strength and deformability based on lithology and structure.