Consider the following statements regarding different types of dams 1. A gravity dam resists the horizontal water pressure primarily through its own weight and its design must ensure stability against sliding and overturning. 2. Embankment dams are generally constructed using compacted earth or rock materials and their safety largely depends on proper seepage control measures. 3. Concrete dams are typically suitable for narrow valleys with strong foundations and temperature stresses may develop in such dams during construction. Which of the statements given above are correct?
- A1 and 2 only
- B2 and 3 only
- C1 and 3 only
- D1, 2 and 3Correct
Solution
Concept
Types and Characteristics of Dams
Formula
N/A
Step-by-step solution
1. Analyze Statement 1: Gravity dams maintain stability against sliding and overturning using self-weight (Correct). 2. Analyze Statement 2: Embankment dams are built of earth/rock materials and rely heavily on seepage control (Correct). 3. Analyze Statement 3: Concrete dams are used in narrow valleys with strong foundations and experience thermal stress (Correct). 4. Select Option D (1, 2 and 3).
Explanation
All three statements are correct. Statement 1 is true because gravity dams use their heavy weight to resist water pressure and prevent sliding or tipping over. Statement 2 is correct because embankment dams are made of earth or rock, making proper seepage control vital to stop water from washing away the material. Statement 3 is true because concrete dams need strong valley walls for support, and heat generated while large amounts of concrete dry creates temperature stresses during construction.
Shortcut
To remember the key features of different dam types, use the rule "G-E-C" (Gravity, Embankment, Concrete): - Gravity (G) = Heavy Weight: Resists water pressure, sliding, and overturning through its own weight. - Embankment (E) = Earth & Seepage: Built of earth/rock fill where seepage control is the top priority. - Concrete (C) = Canyon & Heat: Ideal for narrow valley canyons with strong foundations, with heat of hydration causing thermal stresses during construction.
Common mistake
A common mistake is selecting option A or C by assuming that temperature stresses caused by heat of hydration during mass concreting are negligible, thereby falsely treating statement 3 as incorrect. Another frequent mistake is selecting option A by overlooking the vital role of seepage control in preventing piping failures in earth and rock-fill embankment dams.
Correct answer: D) 1, 2 and 3