Stress and Strain

Question 1

Stress

Answer 1

is the force applied to rocks

Question 2

Strain

Answer 2

is the deformation caused by the applied forces

Question 3

Main factors affecting stress and strain

Answer 3

Temperature, Confining pressure, strain rate, water

Question 4

Confining stress

Answer 4

The pressure due to the weight of overlying rocks - equal in all directions

Question 5

Tension

Answer 5

is the force trying to pull rocks apart

Question 6

Compression

Answer 6

is the force trying to push rocks together

Question 7

Shear

Answer 7

act along a plane in the rock and promote sliding along that plane

Question 8

Competent rocks

Answer 8

are strong and brittle and tend to joint and fault

Question 9

Incompetent rocks

Answer 9

are weak and plastic and tend to fold and develop cleavage

Question 10

Elastic deformation

Answer 10

Wherein the strain is reversible

Question 11

Ductile deformation

Answer 11

Wherein the strain is irreversible

Question 12

Fracture

Answer 12

Irreversible strain wherein the material breaks

Question 13

Brittle materials

Answer 13

Have a small or large region of elastic behaviour but only a small region of ductile behaviour before they fracture

Question 14

Ductile materials

Answer 14

Have a small region of elastic behaviour and a large region of ductile behaviour before they fracture