Week 1- Rock Mechanics Flashcards
What are the common modes of rock failure relevant to engineering geology?
Rock falls
Rock toppling
Rock slides
Cavity collapses
Shear failure will occur if what equation is satisfied? Define each attribute of this equation
Tau > S0 + mu*sigma
Tau - shear strength
S0 - cohesional resistance to motion
Mu - frictional resistance coefficient
Sigma- normal force
List, from weakest to strongest, rock strengths under various stresses
Tensile strength > Shear strength > Compressional strength
What is stress?
Force per unit area
What is the term that defines isotropic stress in a fluid?
Pressure
Define strain
Deformation in a unit length, area, or volume
What is the equation that represents elasticity?
Stress (sigma) / Strain (epsilon)
Define deformation
Change in shape or size of an object in response to an applied stress
3 types of strain
- Elastic (recoverable)
- Brittle (rupture)
- Ductile (plastic)
Give the two Poisson ratios for strain and the third that couples the two
- Epsilon= (L-Lorignal)/Loriginal
- Epsilon1= (B-Boriginal)/Boriginal
- V=abs(Epsilon1/Epsilon)
Define elastic deformation
A temporary change in shape or size that is recovered when the applied stress is removed
How would one define a material if the response of the material to the load/unload is instantaneous?
Pure elastic
Define visco-elasticity
When a material needs finite time to return to its original state in response to load/unloading
Define ductile deformation
A flow-like/bendy permanent change in shape or size that is unrecoverable
Define brittle deformation
The loss of cohesion of a body under the influence of deforming stress (I.e. it breaks, rupture)
