Drainage Gallery

Q.

A concrete gravity dam section is shown in the figure. Assuming unit weight of water as $10kN/m^3$ and unit weight of concrete as $24kN/m^3$ the uplift force per unit length of the dam (expressed in kN/m) at PQ is

1. 16250
2. 32500
3. 21000
4. 10500

Q. Consider the following statements related to uplift pressure in gravity dams :

1. A drainage gallery reduces the uplift pressure at all levels below the gallery.
2. A drainage gallery below upstream water level reduces the uplift pressure at all levels below the upstream water level.
3. A grout curtain near the heel reduces seepage and uplift pressure everywhere on the gravity dam whatever the upstream water level.

Which of the above statements are correct?

1. 2 and 3 only
2. 1 and 2 only
3. 1 and 3 only
4. 1, 2 and 3

Q. A gravity dam of 84 m height is built over a river. The upstream and downstream height of the water level is 80 m and 6 m respectively. Base width of the dam is 56 m and a drainage gallery is provided at 8 m from the heel of the dam. The total uplift force due to seepage forces only per unit length of the dam (expressed in kN/m) is ________

1. 12975.36