Kenan Gelisli

Assessing the factor of safety using an artificial neural network: case studies on landslides in Giresun, Turkey

In this study, the calculability of slope stability using the artificial neural networks (ANN) method was examined. Initially, 100 synthetic slope models were created to be used in calculations and the factors of safety of these slopes were calculated by a conventional stability calculation method using slope parameters. Then, factors of safety were calculated by through ANN method. 80 of the datasets from the generated data were used for training while 20 were used for testing in these calculations with the ANN method. In both conventional calculation of stability and the ANN method, input parameters included slope height, height of the water level, slope angle, unit weight, cohesion and angle of internal friction, while the output parameter was factor of safety (SF). A good level of consistency was obtained between the SFs calculated through the conventional method and the ANN method. Furthermore, SFs were calculated separately via the ANN method by assigning range values to unit weight, cohesion and angle of internal friction from amongst the parameters that affect SF for Giresun landslides (Eastern Turkey). The data obtained in this scope revealed that cohesion was the parameter with the highest level of effect on SF. Consequently, it was established that the factors of safety of slopes could be calculated by means of the ANN method in a rapid and convenient manner, the effects of slope parameters on the factors of safety in landslide were examined and the factors of safety for Giresun landslides were calculated through the ANN method.

Seismic tomography and surface wave analysis based methodologies on evaluation of geotechnical properties of volcanic rocks: A case study

Economic development, industrialization and dense population in Trabzon City have caused residential construction to increase by 300% in the last decade. The settlement area is mountainous and covered with heavy vegetation. Thus, the steep-sided topography and heavy precipitation means floods and landslides are common and in areas with little flat land. Since the mass movements in some parts of city create an enormous danger for buildings, site selection for residential areas becomes increasingly important. This paper describes geotechnical and seismic properties of Tertiary volcanic rock and establishes the link between these units and construction. In this study, refraction tomography and multichannel analysis surface wave methods were applied in order to seek the best construction site in the residential area. The results of the geophysical study were compared with the borehole applications. A series of geomechnical tests were carried out on the core samples. Following that, statistical correlations were conducted by regression analysis to evaluate relationships between measured parameters. Rock Quality Designation and weathering degree were also determined. The methodology defined in this investigation proves to be an appropriate approach to determine geotechnical properties of the foundation rocks and soils and a proper guide on future geotechnical studies for other cities.

Ultrasonic investigations of marble columns of historical structures built in two different periods

Ultrasonic methods are commonly used in structural investigation of historical buildings because they are easily applicable and produce rapid results. Information about strength of museums, mosques, and building structures can be obtained using ultrasonic waves. Turkey is located in a region where destructive earthquakes take place frequently. Buildings suffer significant damage from the earthquakes and deterioration over time. Therefore, the bearing systems of historical monuments should be investigated and protective measures, if necessary, should be taken. This study aims to analyze the marble columns of Hagia Sophia museum, built in the thirteenth and Gülbahar Hatun Mosque, built in the fifteenth century by using ultrasonic measurements and to compare with each other. These two buildings are among the most important historical structures in the Eastern Black Sea region of Turkey. Ultrasonic velocity distribution of marble columns was obtained from ultrasonic measurements with specific data acquisition. The velocity maps were analyzed and compared with both literature values and one another. The qualities of the main columns in the structures were determined through the use of some semi-quantitative calculations. The results show that the columns of Gülbahar Hatun Mosque were of low quality and that its columns had micro cracks. However, the columns of Hagia Sophia museum are in better condition.