Full Length Research Paper

Seismic slope stability analysis: A case study of Gurpinar, Istanbul

Ferhat Ozcep¹*, Engin Erol², Fatih Saraçoğlu³ and Mustafa Haliloğlu⁴

¹Department of Geophysical Engineering, Faculty of Engineering, Istanbul University, Istanbul, Turkey.

²Granit Jeofizik, Catalca, Istanbul, Turkey.

³SRC Geoteknik ve Deprem Mühendisliği, Istanbul, Turkey.

⁴Jeoson Yeraltı Araştırma ve İnşaat Merkezi, Istanbul, Turkey.

*Corresponding author. E-mail: ferozcep@istanbul.edu.tr.

Accepted 17 February, 2010

Abstract

Slope failures triggered by earthquakes are one of the most important soil problems.  In this study, dynamic (earthquake) slope stability analysis was carried out in Gurpınar area. For this aim, in situ tests (SPT) were carried out and laboratory samples were obtained from 6 boreholes (max. depth 50m) to determine soil classification and strength characteristics. Moreover, geophysical studies (seismic refraction and MASW) were also carried out in the area to estimate the structure and strength characteristics of the slope to 50 m. All data, obtained in the field and laboratory, were used to construct the mechanical and structural (geometrical) behaviors of the slope.  To solve slope stability problem, a tree soil slope model was considered for the area. In a dynamic state, to estimate earthquake acceleration, seismic hazard analysis was carried out in the region. At the end of the analysis, while there is no problem in static condition/loads, some slope stability problems appeared with increasing earthquake acceleration. A geotechnical slope improvement project was proposed for the study area.

Key words: Seismic slope stability, earthquakes, Gurpinar, Istanbul.