What is meant by **elastic behavior** of a rock?
A
It deforms permanently under load
C
It returns to its original shape after removal of load
D
It breaks immediately after loading
Analysis & Theory
Elastic behavior refers to temporary deformation that is fully recoverable.
A rock under **plastic behavior** will:
C
Deform permanently without returning to original shape
Analysis & Theory
Plastic behavior results in permanent deformation after the yield point.
What is **creep** in rock mechanics?
A
Sudden failure under high load
B
Gradual deformation under constant stress over time
C
No change in shape under stress
D
Vibration under repeated loading
Analysis & Theory
Creep is time-dependent deformation under a constant load.
Which instrument is used to measure **deformation** in underground openings?
Analysis & Theory
Extensometers monitor deformation and displacement inside boreholes or rock masses.
**Stress-strain behavior** helps in determining:
B
Elastic modulus, yield strength, and failure point
Analysis & Theory
Stress-strain curves give mechanical properties like stiffness, ductility, and strength.
The **flat jack** method is used to measure:
Analysis & Theory
Flat jack tests estimate in-situ stress in rock structures.
Which instrument is commonly used to measure **pore water pressure** in rocks?
Analysis & Theory
Piezometers are used to measure water pressure within rock or soil.
**Ductile behavior** in rocks means:
A
Breaks without any deformation
B
Deforms plastically before failure
D
Has no tensile strength
Analysis & Theory
Ductile materials deform significantly before failure, absorbing energy.
Which device measures **displacement and movement** in rock masses over time?
D
Sand replacement device
Analysis & Theory
Crack meters detect and measure displacement across cracks or joints.
**Rockburst** is a result of:
C
Sudden release of built-up stress
Analysis & Theory
Rockburst is a violent failure due to sudden release of stored stress in deep underground excavations.
Which of the following describes **brittle failure** in rocks?
A
Slow deformation over time
B
Sudden fracture without much deformation
Analysis & Theory
Brittle failure occurs with minimal deformation, often suddenly and violently.
A **load cell** in rock testing is used to measure:
A
Temperature of the specimen
Analysis & Theory
Load cells accurately measure applied force or stress in a test setup.
What does the **vibrating wire strain gauge** measure in rocks?
Analysis & Theory
Vibrating wire gauges measure changes in strain based on frequency change in a wire.
Which property is typically monitored using a **convergence meter**?
C
Deformation or closure of tunnels
Analysis & Theory
Convergence meters monitor the inward movement of walls or roofs in underground excavations.
The instrument **tell-tale** is used for measuring:
Analysis & Theory
Tell-tales visually indicate movement across rock joints or roof strata in mines.