Effects of berm characteristics on earth-fill dam stability


Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2017

Thesis Language: English

Student: YASİN KILIÇ

Principal Supervisor (For Co-Supervisor Theses): Ali Melih Yanmaz

Co-Supervisor: Melih Çalamak

Abstract:

One of the causes of failure in earth-fill dams is the slide of the slope. For this reason, slope stability is a crucial issue for dam safety. There are some precautions to increase the safety of earth-fill dams, and constructing berms on upstream or downstream sides is one of these ways. In this study, effects of berm properties on dam stability are investigated with a case study. The effects of different berm heights, numbers and widths on the stability of Hancağız Dam, Turkey, are analyzed by using three software. The safety factors of slopes, seepage rates through the body, and the pore water pressures in the embankment are obtained under steady-state, rapid fill, and rapid drawdown conditions. Results show that increasing the berm height, number or width of berms provides higher safety factors for the slope where berm is built on. Increasing the berm height is beneficial up to a certain level. Further increase in the berm height causes lower safety factors for the slope. Any changes made on upstream berms do not affect the safety of the downstream slope and vice versa. It is also found that the berm geometry has negligible effect on water flux and pore water pressure in the embankment.