ملخص
Abstract
In this study, seepage phenomena through the foundation of Megenin dam are investigated. Most of the recorded dam’s failure around the world are related to seepage problems. Therefore to avoid failure of earth dams due to seepage, settlement, and piping, continuous field observations are essential. The Megenin dam is a 38 m high rock fill dam. A concrete cut-off wall and grout curtain were constructed below the dam body to prevent reservoir seepage through the foundation.The dam was constructed in 1972, for two main purposes; first to control floods for the cultivated fields downstream and to protect Tripoli city, secondly to collect water for irrigation. On 15thMay 2003 during the 3rd filling, the water level in the reservoir reached 271.86 m, while seepage water was observed in the wadi bed downstream of the main dam. This phenomena were also observed in previous times. The Piezometric water level was much higher compared to that previously measured. To assess the seepage phenomena and the impact on dam safety, the folowing were applied: the technique of ground penetrating radar survey (GPR), piezometric analysis, and temperature field evaluation. Constructed a flow net model for the dam.The results of the study showed that: GPR profiles describe critical zones in the dam site. Identify the water seepage paths from dam reservoir to down stream of dam.Determine the amount of total water seepage capacity through the dam foundation (Q= 0.08 Ɩ / s ).The essential points to avoid any problem that may occur in the future in Megenin dam due to seepage problems.