Influence of water level reduction on stability of zoned earth dam

Abstract

The zoned earth dam is the most type of dam that constructed in Thailand since it can be used as its purposes. With the installation of instruments, the behavior of dam can be measured for long term use. However, the simulation of water level reduction in the dam, which is an important factor for the stability of dam, is necessary. Therefore, the aim of this research is to study the rate of water level reduction at 0.25, 0.5, 0.75 and 1.00 m./day and the change of water level at 1/2, 1/4, 1/8 and 1/16 compared with difference of normal water level and minimum water level of dam. There are 2 cases study, Pasak Chonlasit Dam and Muak Lek Reservoir. From the results, it is found that the change of water level has much effect to the stability of dam. The factor of safety decreased with the increasing of reduction of water level. But for the rate of water level reduction has little effect to the factor of safety. The reduction of water level should not over than 1/4 time of the difference of normal water level and minimum water level of dam.