Browsing by Author "Topal, T."

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Evaluation of Shear Wave Velocities Using Spt-Based Uphole: a Case Study From Erbaa (tokat-Turkey)
(Crc Press-taylor & Francis Group, 2013) Akin, M. K.; Kramer, S. L.; Topal, T.
The study area, Erbaa, is located along the eastern segment of North Anatolian Fault Zone (NAFZ) and is one of the largest towns of Tokat in Turkey. After the disastrous 1942 (M-s = 7.2) and 1943 (M-s = 7.6) earthquakes, the center of Erbaa was shifted southwards. As a part of a seismic microzonation study, shear wave velocity profiles of Erbaa were developed to perform site response analyses. A modified and a new form of the seismic uphole method which uses the impact energy of the split spoon sampler of SPT test as a source was applied in this study (SPT-based uphole method) to obtain shear wave velocity measurements. In this method, it is aimed to record the shear waves during the SPT test without any additional explosives or mechanical sources. The recorded shear wave velocities are evaluated to define the shear wave velocities of the soil profiles in Erbaa.
Evaluation of the Rockfall Potential of Kastamonu Castle Using 3-D Analysis
(Springer Science and Business Media Deutschland GmbH, 2013) Akin, M.; Topal, T.; Akin, M.K.
The Kastamonu Castle is one of the magnificent monuments of the Kastamonu province (Turkey) located on a steep sandstone hill with Eocene age. The surrounding settlement around the castle suffered from numerous rockfall events in the past. Rockfalls after an initial block toppling are controlled by a bedding plane and two joint sets existing in the sandstone. The rockfall potential along the entire castle perimeterwas evaluated bymeans of three-dimensional (3-D) rockfall analyses using the ROTOMAP software. Rockfall initiation wasmodelled along a detachment line situated just below the castle walls. The results indicate that the maximum run-out distances around the castle exceed the settlement boundary on the western, southern, and eastern sides. The northern part of the castle is less critical due to lower slope gradient. In order to protect the settlement from falling blocks, vital remedial measures are suggested. © Springer-Verlag Berlin Heidelberg 2013.
The Potential of Liquefaction-Induced Lateral Spreading in Erbaa (tokat-Turkey)
(Crc Press-taylor & Francis Group, 2013) Akin, M. K.; Kramer, S. L.; Topal, T.
The liquefaction potential of Erbaa (Tokat) in Turkey settlement has been evaluated in this study. The study area is located partly on an alluvial plain of Kelkit river within the North Anatolian Fault Zone (NAFZ). In order to investigate the liquefaction potential of the area, geotechnical investigations including geological mapping, drilling with in-situ tests and sampling were conducted. Based on the analysis, the potential of liquefaction-induced lateral spreading displacements are investigated as a part of the microzonation study of Erbaa. The empirical methods proposed to estimate liquefaction-induced lateral spreading employ the ground inclination and the thickness of liquefiable ground layer generally through regression analyses. The northwestern part of Erbaa reveals a higher lateral spreading displacement potential than the rest of the study area considering lateral spreading analyses.
Rockfall Hazard Analysis for an Historical Castle in Kastamonu (Turkey)
(Springer, 2012) Topal, T.; Akin, M. K.; Akin, M.
The Kastamonu Castle located on a sandstone hill with Eocene age is one of the most historical and touristic places in Kastamonu city center. The settlement of the city expanded towards the hill of the Kastamonu Castle and adversely affected by rockfalls in the past. The rockfall problems around the castle could be related to jointing, weathering, freezing-thawing and earthquake effects or a combination. In this study, the rockfall hazard at the castle is evaluated by two-dimensional rockfall analyses along 17 profiles selected in different orientations. Different size of rock blocks and various types of movements are taken into consideration in the analyses. Fall-out distance, bounce height, kinetic energy and velocity of the sandstone blocks are separately evaluated. The obtained data are used to define the possible rockfall hazard zones. Finally, the areas having potential rockfall risks are distinguished. Based on the evaluation of the data, rock bolting after removing of unstable blocks and supporting the area with the protective fences are suggested.
The Rockfall Potential of the Southwestern Part of Kastamonu Castle (Turkey) Based on 2-D and 3-D Analyses
(Springer International Publishing, 2014) Akin, M.; Topal, T.; Akin, M.K.
Urbanization around steep rock slopes with jointed rock masses is mostly under the threat of rockfalls. Numerous catastrophic rockfall hazards have been reported throughout the world due to the downslope movement of detached rocks. It is quite critical to determine the rockfall potential of a location considering rockfall trajectories, run-out distances, bounce heights and the kinetic energies of falling rocks. Therefore, the determination of rockfall paths requires the use of rockfall simulations. In practice, 2-D and 3-D models are most commonly employed during rockfall event modeling. The rockfall trajectories are simulated on a slope profile with X and Y axis in 2-D models, whereas 3-D models encompass a real space with X, Y and Z axis to calculate the rockfall paths. In this study, the rockfall potential of the southwestern part of the Kastamonu Castle, which is situated on a steep sandstone hill, was evaluated on the basis of 2-D and 3-D rockfall analyses using RocFall v.4.0 and ROTOMAP software, respectively. The close vicinity of the Kastamonu Castle, especially the southwestern region, is surrounded by residential houses and these settlements were adversely affected by disastrous rockfalls in the past. Based on 2-D and 3-D simulations, two different preliminary rockfall hazard maps were prepared and rockfall high-risk areas were defined. Both the 2-D and 3-D analyses pointed out that the southwestern part of the castle is under the great danger of rockfalls of which the weight of falling blocks may reach up to 10 tons. Finally, it is concluded that the maximum fall-out distances in 3-D analyses are more remote than those of 2-D analyses in the study area. © Springer International Publishing Switzerland 2014.