Harmandalı (İzmir) atık depolama sahasının mühendislik jeolojisi

Harmandalı (İzmir) waste disposal site has been put into service on 1996 and managed by the Metropolitan Municipality of Izmir and waste management office. In February 2013, a landslide hit Harmandalı waste disposal site and affected the administration buildings and a truck scale in this area. Also, in March 2016 another landslide occurred in the area. These events resulted in mass movement in the Harmandalı landfill site. As well as, this mass movement reactivates by new external and internal factors for instance rainfall, seismic activity, earthquakes, etc. Two geophysical methods were conducted in the area in order to determine the sliding surface in Harmandalı waste disposal site; Electrical Resistivity Tomography (ERT) and Multichannel Analysis of Surface Waves (MASW). Surveys included two lines of Electrical Resistivity Tomography surveys which laid out parallel and perpendicular to landslide direction. Two ERT profiles were conducted to map resistivity distribution of the surface. The resistivities were classified into three categories; low, middle and high values. Comparing with geological studies, the low values of resistivity was indicated to leachate, water and clay. The second geophysical method MASW was carried out in the area using 7 profiles to obtain Rayleigh wave dispersion curves for estimation of shear wave velocity profiles to 30 m depth of the area. Three of the MASW profiles were parallel to the landslide direction and four of them were perpendicular to the landslide direction. The results of MASW surveys included seven of 1D S-wave velocity profiles and two of 2D S-wave velocity profiles. The results indicated that there are three velocity zones in the area; high, moderate and low values. The low values of velocity from the MASW surveys refer to sliding surfaces which were affected by existence of water and high plasticity clay. According to the geophysical results, the essential depth of the sliding surface in the study area is about 9 meter in SK-8, 22 meter in SK-3, 15 meter in SK-5 and 10 m in SK-2.