Correct Answer - Option 1 : gravity
Explanation
A gravity dam is a structure that is defined in such a way that its own weight resists external forces.
The maximum possible height (limiting height) of the dam is given by:
\({H_{max}} = \frac{f}{{{\gamma _w}\left( {{S_c} + 1} \right)}}\)
A low gravity dam is the one whose height is less than Hmax.
A high gravity dam is the one whose height is greater than Hmax.
A gravity dam is called a low dam if the base width is designed from the consideration of the resultant falling as close as possible to the extremities of the middle third of the base.
2) A buttress is a pier of masonry built as an integral part of the wall, decreasing in cross-section from base to top. It provides support to the wall.
