USBR ch 4

Question 1

Dams are classified according to their use, their hydraulic design or the material of which are constructed.

T or F

Answer 1

True

Question 2

The purpose of Detention Dams are ordinarily constructed to retard flood runoff and increase the effects of sudden floods

T or F

Answer 2

False

Question 3

Earthfill dams are the most common dams used because they are principally constructed of the material from local natural material. Requiring minimum processing

T or F

Answer 3

True

Question 4

What is the membrane of rockfill dam made of?

a) a concrete slab
b) asphaltic concrete paving
c) steel plates
d) all above

Answer 4

d) all above

Question 5

Concrete arch dams are suitable for sites where the ratio of the width between abutments to the height is greater and where the foundation at the abutments is not solid rock capable of resisting arc thrust

T or F

Answer 5

False

Question 6

The single arch dam spans a canyon as one structure and is usually limited to minimum crest length to height ratio of 20:1

T or F

Answer 6

False

Question 7

A timber dam is not economical for modern construction because the amount of labor involved in a timber dam, coupled with short life of the structure make this uneconomical.

T or F

Answer 7

True

Question 8

What are some of the advantages of a rock foundation for a dam?

a) free of significant geology defects
b) are resistant to erosion and percolation
c) have low shear strength
d) both A and B

Answer 8

d) both A and B

Question 9

What type of design concerns should be considered if a silt of fine sand foundation is available?

a) include non-uniform settlement
b) prevention of piping (cock-blocking)
c) excessive percolation losses
d) uplift forces
e) potential soil collapse upon saturation

Answer 9

a) include non-uniform settlement
b) prevention of piping
c) excessive percolation losses
d) uplift forces
e) potential soil collapse upon saturation