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Over the course of history Marmara region in Northwestern Turkey has been the site of numerous destructive earthquakes. Based on historical and instrumental earthquake records, the Marmara sea region is one of the most seismically active regions of the Eastern Mediterranean. The Marmara region is under the influence of the western part of the North Anatolian Fault Zone (NAFZ) and the N-S extensional regime of Western Turkey. Therefore, the earthquake risk analysis is very important for the MARMARAY Project. 76 km-long MARMARAY Project is an important project not only for Turkey but also for the world because it joins the two continents through railway. It will also serve for a comfortable and healthy way of environment, providing a contemporary solution for urban transportation. Geotechnical and geological parameters of the region were obtained from analyses of seven boreholes. In this paper, using average wave velocities in layers, thickness, density and formation data based on the PS logs, 43 m and 65.5 m depths ranging from 7 different boring logs in a ground-wise different geological regions in İstanbul, ground response functions were obtained. Based on the soil profiles transferred to EERA (Equivalent-Linear Earthquake Site Response Analyses of Layered Soil Deposits) and NERA (Nonlinear Earthquake Site Response Analyses of Layered Soil Deposits) softwares, the rock soil record of August 17, 1999 Kocaeli earthquake in İstanbul-Beşiktaş Ministry of Public Works and Settlement (IBMPWS), response and design spectrums that may be considered crucial in case of an earthquake were obtained. The acceleration record was used as an input motion having PGA value of 0,04287 g (east-west component) which was applied on sublayers (i.e. sand, gravel, clay) using EERA and NERA programs. The analysis is done by keeping constant damping ratio of 5%. Also nonlinear analysis was compared with the linear method of analysis. Stages involved in ground response analyses to develop site-specific response spectra at a soil site are summarized. Some of the known site response analysis methods are summarized and similarities and diff erences between linear and nonlinear methods.

The basic friction angle is a basic parameter used in the shear strength estimation of discontinuities. The accurate determination of the shear strength of the discontinuities is of great importance for engineering structures built on or inside the rock. In this study; the variation of the basic friction angle tests under dry and different fluid conditions were carried out. For this purpose, a tilt device was designed. 7 different types of travertine samples with dimensions of 10×10×2 cm were used in the experiments. Tilt tests; to determine the change of the basic friction angle under different liquid conditions, dry, pH2, pH7 and pH12 were carried out under different test fluid conditions. Basic friction angles were measured 5 times in each group experiment. Initial basic friction angles were high regardless of sample type and experimental conditions. But; as the measurements continued, significant changes were observed about slip angles. The lowest basic friction angle was obtained in samples conditioned with pH2 while the highest angle was obtained in samples with ph7 conditioned. Thus, the effect of different water contents on sliding surfaces was determined experimentally. It is thought that this study can contribute to the existing studies on the basic friction angle with the tilt test.

The basic friction angle (φb) tests are a common and practical method used to determine the shear strength of discontinuities. Tilt device is generally used in basic friction angle experiments. In this study, the effects of the anisotropy properties of green and mica schist rocks taken from the copper mine site in Kastamonu Hanönü district on the basic and residual friction angles were investigated. For this purpose, experiments with a specially designed tilt device were conducted on dried and saturated green schist and mica schist samples with orientation angles of 0°, 15°, 30°, 45°, 60°, 75° and 90° relative to the loading axis. According to the results in dried and saturated conditions, maximum basic and residual friction angle values were obtained for green schist samples at 60°. The results were close to each other in the experiments carried out in both saturated and dried conditions. Green schist samples were less affected by the saturated media. Mica schist samples were not affected by anisotropy for both media, and close values were obtained in all orientation angles. It was determined that the basic and residual friction angles were lower in saturated conditions compared to dried ones.

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