This set of Engineering Geology Multiple Choice Questions & Answers (MCQs) focuses on ” Joints Terminology”.
1. What is responsible for jointing of rocks?
b) Forces acting on the rock
c) Genesis and various forces acting on the rock
Explanation: We may find quite a large proportion of outcrop of any of these rocks practically free from joints at some places, but at other places the same type of rock may be heavily jointed, showing cracks of greater variety. Hence it is not only genesis of the rocks which responsible for these structures but also the forces acting on them.
2. Fractures along which there has been no relative displacement is called
Explanation: Joints are defined as divisional planes or fractures along which there has been no relative displacement.
3. State true or false. Joint is always accompanied by opening.
Explanation: Joints may be open or closed. Open joints are those in which the blocks have been separated or opened up for small distances. In closed joints, there is no such separation.
4. The open joints are gradually enlarged due to
Explanation: Open joints are those in which the blocks have been separated or opened up for small distances in a direction at right angles to the fracture surface. These may be gradually enlarged by weathering processes and develop fissures in the rocks.
5. The type of joint usually found is
a) Open joints
b) Close joints
c) Open and close joints
d) Faulted joints
Explanation: There may be or may not be an opening up of blocks perpendicular to the joint planes. Hence the joints may be of open or close nature.
6. When the joints are prominent and extending for considerable depth they are called
a) Continuous joints
b) Discontinuous joints
c) Deep joints
d) Prominent joints
Explanation: The joints which are quite prominent and extending for considerable depth and thickness are called as continuous joints.
7. What are the continuous joints also called?
a) Uniform joints
b) Normal joints
c) Prime joints
d) Master joints
Explanation: The continuous joints are also called often as master joints. Almost all joints are discontinuous in the strict sense because these disappear with depth in the crust of the earth.
8. The streaks or bands filling material in the rocks are called
a) Colour pigments
Explanation: In many cases, open joints get filled up by solutions of secondary materials which crystallize or precipitate there forming thin or thick streaks or bands of the filling material. These are simply called veins.
9. When the thickness is greater than 20 cm, the veins area called
a) Thick veins
b) Fissure veins
c) Joint veins
d) Broad veins
Explanation: The thin or thick filling material in the joints of the rocks are called as veins when thin and when their thickness exceeds 20 cm they are called fissure veins.
10. Joints do not have dip and strike. State true or false.
Explanation: Joints have dip and strike, the dip being their inclination with the horizontal and the strike being the direction of intersection of a joint plane with a horizontal plane.
11. Pick the wrong statement.
a) A joint set is a group of joint surfaces
b) The surfaces trend in same direction
c) The surfaces have almost same dip
d) The joint surfaces do no trend in same direction
Explanation: A joint set is a group of two or more joint surfaces trending in the same direction with almost the same dip.
12. Group of joint sets are called
a) Joint system
b) Joint group
c) Joint class
d) Joint collection
Explanation: A joint system is a group of two or more joint sets. A joint set is a group of two or more joint surfaces trending in same direction with almost same dip.
Sanfoundry Global Education & Learning Series – Engineering Geology.
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