Question

What is the most critical condition of slide of the U/s slope?

(a) The sudden drawdown of the reservoir

(b) Reservoir full condition

(c) Steady seepage condition

(d) Sudden drawdown and reservoir full condition

I had been asked this question at a job interview.

Asked question is from Failure of Earthen Dams topic in portion Earthen and Rock Fill Dams of Irrigation Engineering

Answer 1

Correct choice is (a) The sudden drawdown of the reservoir

For explanation I would say: When the upstream slope is steep and when the soil used in the construction of the dam is poor and compaction is not adequate, the sudden drawdown of water causes sliding of the upstream face. This failure seldom leads to catastrophic failures.