WorksheetsChapter 2: Description of Discontinuities
Total questions: 20
Worksheet time: 11mins
The followings are the types of discontinuities, EXCEPT:
Joint
Cleavage
Fault
Rock mass
Following statement are referring to:
"Repetitive layering in metamorphic rocks.
Each layer may be as thin as a sheet of paper, or over a meter in thickness.
Caused by shearing forces (pressures pushing different sections of the rock in different directions), or differential pressure (higher pressure from one direction than in others)."
Schistosity
Fault
Foliation
Cleavage
Fracture or crack are:
Divides the rock into two or more pieces
Any separation in a geologic formation
Caused by stress exceeding the rock strength, causing the rock to lose cohesion along its weakest plane
ALL of the above.
What is borehole?
The state of rock cores recovered is largely a function of the drilling method, and the amount of core employed by the driller during a core run and extraction of core from the core barrel
An excavation of ground in order to study or sample the composition and structure of the subsurface
A deep vertical hole of small diameter bored into the earth to ascertain the nature of the underlying strata or to obtain water.
All of the above.
The following was the purposes of drilling borehole, EXCEPT:
Monitoring
Drilling for water and water abstraction
Access to a tunnel or underground structure, also as an escape route
Mineral exploration, including sand and gravel
Trial pit usually safely excavated to a depth of about 1.2m using hand tools assuming the sides of the trial pit are stable.
True
False
Weathering is a process of breakdown of rocks at the Earth’s surface, by physical, chemical and biological activity.
True
False
Many data relating to discontinuities can be obtained from photographs of exposure.
Photographs may be taken looking by all of the following EXCEPT:
Vertically from the air.
Direct measurement on the ground.
Horizontally at the rock mass from the ground.
Obliquely, down at the outcrop.
Measurements of discontinuity survey should be taken over distances of about 10 m and to ensure the survey is representative, the measurements should be continuous over that distance.
True
False
What type of discontinuities is this?
Fracture
Cleavage
Foliation
Fault
Name this..
Normal fault
Reverse fault
Strike fault
Fault plane
Identify the engineering applications for rock mass classification.
Foundations
Tunnels
Slopes
All of the answer are correct
What is the objectives of rock mass classification?
As a ventilation of a tunnel or underground structure
Relate the experience of rock conditions at one site to the others.
Control the engineering performance of a rock mass and not the rock material
Name this method of drilling borehole.
Hand auger
Shell & auger rig
Air flush drilling
Small scale rotary drilling
Shafts construction can be temporary ONLY.
True
False
What is the difference between a joint and a fracture?
Joints have no displacement across the fault plane, fractures do.
}Formed through failure of rock masses in tension, in shear or through some combination of both.
No different at all.
What is a strike slip fault?
the motion is perpendicular to the strike line of the fault plane
the motion is parallel to the strike line of the fault plane.
All the followings are the records of borehole EXCEPT
Geotechnical data
Samples
In situ testing
Weathering
What is core recovery state?
A deep vertical hole of small diameter bored into the earth to ascertain the nature of the underlying strata or to obtain water.
largely a function of the drilling method, and the amount of core employed by the driller during a core run and extraction of core from the core barrel
An excavation of ground in order to study or sample the composition and structure of the subsurface.
Solid core in core recovery is
> 0.15 m in width
< 0.15 m in width
> 0.1 m in length
< 0.1 m in length
