Analysis of Unsteady Seepage Behavior of Rumei High Core Wall Rockfill Dam by FEM

Abstract

The Rumei core wall rockfill dam hydropower station is in Lancang River in the Mangkang county of the Tibet autonomous region with maximum height of 315m and crest length of 666.2m. Due to the high core wall rockfill dam has been more than 300m high, water level sudden drawdown of the unsteady seepage condition shall be taken into consideration, according to the given water level drop speed (5m/d) calculate condition, analysis of the seepage field distribution of the different water level, free surface of different time, each material partition of the dam and foundation soil seepage gradient, etc are given. The results showed that the free surface of the upstream dam shell rockfill body dropping fast than the water level dropping speed of the reservoir. The seepage gradient of the upstream shell is very small, which will not cause adverse effect on the upstream dam slope stability. The free surface of the downstream dam shell rockfill body changes little, which will not cause adverse effect on the downstream of the dam slope stability. As the water level falls, the free surface of the core wall dropping speed is slow, far less than the water dropping speed of the reservoir. In the process of emptying reservoir, the free surface of the core wall remains in a high position, which should cause enough attention.