Choose a correct answer for the following: 1- In order to protect the structure from the failure by piping, it must be: A- Increase the depth of the U/S pile C- Increase the length of the floor B- Increase the depth of the D/S pile D- All of the above 2- The U.S.B.R. No. III stilling basin is used when: A-V< 15 m/sec and Fr< 4.5 C-V> 15 m/sec and Fr < 4.5 B- V< 15 m/sec and Fr > 4.5 D- V> 15 m/sec and Fr > 4.5 3- If the equation of the water surface inside a warped transition is (y 0.00156 x2), and the length of this transition is 16m, the total difference between U/S and D/S water level (Ay) is: D-0.02496m A- 0.39936m B-0.09984m C-0.19968m 4- The failure of earth dam by overtopping can occur when: A- The flood design is underestimated C- The spillway gates are not properly operated B- The spillway is insufficient capacity D- All of the above 5- The top level of the core zone in the earth dam should be at least Im above the maximum water level to prevent: A- piping through the body of the dam C- Sepage by capillary siphoning B-Overtopping the dam body D-Erosion of U/S face of the dam 6- In a rectangular channel, if the flow velocity is 11.5 m/sec and the depth of flow is equal to 1.1m, therefore the name of the jump that will occur in this channel is: A- Strong jump B- Oscillating jump C-Steady jump D- Weak jump 7- In the designing of gravity dam, when the acceleration of earthquake is vertical upward, then: A- The weight of the dam is increased C- The uplift pressure is increased B- The weight of the dam is decreased D- The uplift pressure is decreased 8- The height of the jump (Hj) in a rectangular channel is equal to: B- 6.9(y2-yı) C- (4 yı yaAE) A- (yi-y2) D- Non of these 9- The hydraulic jump is an example of : A- flow transition B- Seepage failure C-energy dissipaters D- Non of these 10- Increasing uplift pressure under the conerete gravity dam will lead to A- Decreasing the safety against piping C- Increasing the weight of concrete gravity dam B- Decreasing the overall vertical weight of the dam D- Non of these