Is Arch Dams are the safest and strongest dams ? Is it have any problem in its saftey?

Answer 1

All dams have various levels of natural strength and safety. All types of dams have also suffered catastrophic failures.
The best example I can give you of a concrete dam failure is the St. Francis Dam in southern California, 1928. It was a concrete Gravity Arch dam about 200 feet high. It failed under a full reservior, due to the re-activation of an ancient landslide that composed the dam's left abutment. However, it's twin sister, the Hollywood (Mulholland) Dam, after retrofitting in the early 1930's, has stood strong to this day.
Earthen dams have also failed, such as the Teton Dam in the 1970's.
The Van Norman Dam in the San Fernando Valley (rolled earth fill dam) collapsed during the 1971 Sylmar quake, but didn't fail. It held it's water long enough for emergency crews to lower the water level to a safe point, saving many lives and homes.
The biggest safety concerns for concrete dams are:
1. Is the concrete of sufficient strength, with a well-cleaned aggregate?
2. Is the foundation sound?
3. What kind of siesmic activity can be expected in the area?
4. Are there sufficient seepage galleries and grout curtains to control excess water and prevent piping?

If you're comparing concrete dam types, I'd say an arch dam is at least as safe as a concrete gravity dam (such as Shasta) provided it has firm rock to brace against.

Basically, a dam is a wall that creates an entire lake behind it. Water is very heavy, and will always try to escape. So, as safe as they try to build them, that safety is always tenuous at best.
Check out my website on the St. Francis Dam, at...
http://www.geocities.com/zeebya/integintro.html

Answer 2

They are the safest. Their base and sides are usually embedded in rock. There is very reliable engineering knowledge for their design, some even graphical.
The principle involved is that the resultant of the forces to be considered in the design, is to be maintained within the body of the arch to make it stable. The resultant is the force comprising
all the forces involved and is usually represented by an arrow In the case of a dam the most important force is the water pressure
at the base of the dam.The arc is a very stable structure. It was used widely in ancient buildings that still exist which have survived earthquakes Probably many or all of those arches were designed by trial and error or by repeating the shape of those already existing.

Answer 3

All dams will have failure ultimately.

the arch dam like Hoover dam, the load is transfer to the solid ground horizontally.

In straight dam the load is in the centre of the dam.