Geotechnical Assessment of the Slopes of Hamamok Dam, NE of Koya, Kurdistan Region of Iraq

Bahra Dh. Ghafour; Mohammed J.  Hamawandy; Varoujan K.   Sissakian

doi:10.14500/aro.11553

Bahra Dh. Ghafour Department of Geotechnical Engineering, Faculty of Engineering, Koya University, Danielle Mitterrand Boulevard, Koya KOY45, Kurdistan Region – F.R. Iraq https://orcid.org/0000-0002-3252-5368
Mohammed J. Hamawandy Department of Geotechnical Engineering, Faculty of Engineering, Koya University, Danielle Mitterrand Boulevard, Koya KOY45, Kurdistan Region – F.R. Iraq https://orcid.org/0000-0001-9532-5112
Varoujan K. Sissakian Department of Petroleum Engineering, Komar University of Science and Technology, Chaq Chaq - Qularaisi, Sulaymaniyah, Kurdistan Region– F.R. Iraq. https://orcid.org/0000-0002-9840-5422

Keywords: Bejerman’s method, Factor of safety, Hamamok Dam, Kinematic analysis, Landslide possibility index

Abstract

The Hamamok Dam is an earthfill dam with a height of 25 m and length of 125 m; constructed in 2011; located northwest of Koya town on a deep canyon-like valley that flows along the southeastern plunge of the Bana Bawi anticline; which forms Bawagi Mountain. The exposed rocks in the site belong to the Pila Spi and Gercus formations; however, rocks of the Khurmala and Kolosh formations are exposed upstream from the dam’s reservoir. The difference in the hardness of the carbonate rocks of the Pila Spi Formation which forms the uppermost parts of the cliffs surrounding the dam site and those of soft reddish brown clastics of the Gercus Formation caused steep slopes that suffer from slope instability problems. To assess a geotechnical study of slopes in the dam site, we have collected different field data to perform a Kinematic assessment method using Dip Analyst 2.0 software and draw the stereographic projection for the studied 10 stations using Stereonet v.11 software. Besides Bejerman’s method, which is based on field data only and indicates the Landslide Possibility Index (LPI). The results showed that the L.P.I. values range between 23 and 27, whereas the results of the Kinematic analysis showed that the right bank (Stations 1 – 5) suffers from plane sliding, whereas the left bank (Stations 6 – 10) suffers from toppling. In both cases, Joint 2 has the main role in the developed failures.

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Author Biographies

Bahra Dh. Ghafour, Department of Geotechnical Engineering, Faculty of Engineering, Koya University, Danielle Mitterrand Boulevard, Koya KOY45, Kurdistan Region – F.R. Iraq

Bahra Dh. Ghafour is a lecturer at the Department of Geotechnical Engineering, Faculty of Engineering, Koya University. She got a B.Sc. degree in Geology from Salahaddin University and an M.Sc. in Engineering Geology (Slope Stability Analysis) from Koya University. Her research interests are slope stability analysis, rock mechanics, structural geology, and industrial rocks. Mrs. Bahra is a member of the Kurdistan Geology Society, Sulaimani Branch.

Mohammed J. Hamawandy, Department of Geotechnical Engineering, Faculty of Engineering, Koya University, Danielle Mitterrand Boulevard, Koya KOY45, Kurdistan Region – F.R. Iraq

Mohammed J. Ahmed is a lecturer at the Department of Geotechnical Engineering, Faculty of Engineering, Koya University. He got his B.Sc. degree in Geology/Geochemistry from the University of Baghdad, his M.Sc. degree in Petrology and Mineralogy from the University of Baghdad, and his Ph.D. degree in Sedimentology and Mineralogy from the University of Baghdad. His research interests are in mineralogy, geotechnical engineering, and industrial rocks. Dr. Mohammed is a member of the Iraqi Geologists Union and the Kurdistan Geology Society, Sulaimani Branch.

Varoujan K. Sissakian, Department of Petroleum Engineering, Komar University of Science and Technology, Chaq Chaq - Qularaisi, Sulaymaniyah, Kurdistan Region– F.R. Iraq.

Varoujan K. Sissakian is a chief researcher at the Komar University of Science and Technology, Sulaymaniyah, Iraq. He got a B.Sc. degree in geology from the University of Baghdad and a M.Sc. degree in engineering geological mapping from I.T.C., the Netherlands. His major fields of interest are geological mapping, stratigraphy of the Iraqi territory, site investigation, geological hazards, and mineral exploration. Mr. Varoujan is a member of the Iraq Geological Survey (GEOSURV).

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