A LANDSLIDE THREATENING THE SPILLWAY OF A DAM: AN EXAMPLE OF ÖZEN DAM (SIVAS-TURKEY)

3rd International Scientific Conference - SGEM2003, www.sgem.org, SGEM2003 Conference Proceedings/ ISBN: 954-918181-2, June 9-13, 2003, 167- 176pp

ABSTRACT

Recently, numerous landslides occurred in the southern part of the Özen Dam
(Sivas-Turkey) threatening the spillway. Kinematical analyses showed that the
potential slope instability direction is NW corresponding to the dominant slope
directions. Geotechnical surveys confirmed the rock slopes are highly prone to
instability, and failures occurred in the limits between basement rock and debris
material in the alteration zone as a planar surface. Pre-existing failures,
excavations in the toe of the slopes, low quality of the basement rock unit,
saturation of the earth material on the slope causing an increase of the water
pressure, high slope grades and highway works on the crown part of the landslides
increased the driving forces and decreased the resisting forces. Some stabilization
methods would be useful to decrease the resisting forces and increase the driving
forces, such as; to control of the surface run-off and groundwater level by surface
drain, to change the grade of the slope, buttresses at the toe between slope with
spillway wall.

Key-words: Alteration, dam, landslide, Sivas, spillway, Turkey