Geological and geotechnical investigation of soil in Nazilli city center and near surroundings

This study is aimed to geological and geotechnical investigation of soil in Nazilli settlement area and near surroundings. Nazilli is located in first degree earthquake zone.According to the literary works done so far, between 1900-2006, the number of earthquakes happened (M ? 6) in that area is four and by 1960, at last one destructive earthquake has occurred every 20 years.In the study area, 110 drillings have been conducted to determine the engineering properties of the soils. During the drillings, every 1.5 meter, a SPT has been conducted. From the convenient places, undisturbed samples have been taken by the help of UD sample obtainers Laboratory experiments have been done to determine the physico-mechanical parameters of the soils. As a result, qu values have been investigated between 0.90-1.01 kg/cm2, cu values have been found between 0.45-0.51 kg/cm2, the inner angles of friction have been changed between 24-32 degrees.Groundwater level was measured from the drillings. Groundwater depth changes between 1-18 meters. Based on these measurements groundwater level and depth to groundwater maps were prepared.Liquefaction analysis has been done using connected SPT(N1)60 values and liquefaction potential map was prepared. Furthermore, liquefaction potential index was defined and liquefaction potential index map also prepared using ArcGIS 9.3.1. version. Based on these maps the majority of settlement area in Nazilli has liquefaction risk in a possible earthquake.