1.What are the horizontal forces that are prone to act on a well foundation?
a) Wind force
b) Earth pressure
c) Seismic force
d) All of the mentioned
Explanation: A well foundation is liable to the following horizontal forces: i) force on account of water current ii) wind forces iii) seismic forces iv) earth pressure v) centrifugal forces.
2. The analysis of well foundation is done based on the assumptions of _________
a) Banerjee and Gangopadhyay
b) Lacey
c) None of the mentioned
d) All of the mentioned
Explanation: Based on the assumptions done by Banerjee and Gangopadhyay in 1960, the analysis of well foundation can be done.
3. The maximum depth of scour at the nose of pier is _______ Lacey’s value.
a) Twice
b) Thrice
c) Half
d) None of the mentioned
Explanation: The maximum depth of scour at the nose of the pier, is found to be twice the Lacey’s value of normal scour depth: R = 2RL.
4. Coefficient of horizontal soil reaction m, depends on _________
a) Shape of the area carrying load and Nature of soil
b) Skin friction
c) None of the mentioned
d) All of the mentioned
Explanation: Factor m, called the coefficient of horizontal soil reaction depends on the nature of soil, size and shape of the area which carries the load
5. When a rigid well starts moving parallel, it transforms the soil in to __________
a) Active and passive states
b) Rigid state
c) Loose sand
d) All of the mentioned
Explanation: When a rigid soil, embedded in sand, starts moving parallel to its original position under the action of a horizontal force, it transforms the soil on one side to passive state and the other side in to active state.
6. According to Terzaghi and Peck, the ultimate bearing capacity can be determined by which of the following expression?
a) Q f = Q p + 2πRfs Df
b) Q p = πR2(Q p + 2πRfs Df)
c) Q p = 2πRfs Df
d) All of the mentioned
Explanation: According to Terzaghi and Peck, the ultimate bearing capacity can be determined from the following expression:
Q f = Q p + 2 π R fs Df
Where R = radius of well, Df = depth of well, fs = average skin friction.
7. Laying of the well curb in river bed having water, is done by _________
a) Draining out the water
b) Diverting the water
c) Constructing cofferdams
d) None of the mentioned
Explanation: If water is present in the river, suitable cofferdams are constructed around the site of the well and islands are made.
8. To avoid the setting of the cutting edge unevenly, ___________ can be introduced.
a) Wooden sleepers
b) Smooth oil surface
c) Bottom plug
d) Steining bars
Explanation: It is desirable to insert wooden sleepers below the cutting edge at regular intervals so as to distribute the load and avoid setting of the cutting edge unevenly during concreting.
9. Excavation of soil inside the well in river beds can be done by ________
a) Auger
b) Sending in Workers
c) Special equipment
d) None of the mentioned
Explanation: Excavation and scooping out of the soil inside the well can be done by sending down workers inside the well till the depth of water inside becomes about 1 m.
10. When the well is sunk deeper, the skin friction is decreased by which of the following method?
a) Use of phawrah jhams
b) By tilting and shifting
c) By applying kentledge
d) All of the mentioned
Explanation: To overcome the increased skin friction and the loss of weight due to buoyancy when the well is sunk deeper, additional load known as kentledge is applied on the well.