Browsing by Author "Karaman, Mustafa"

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Effects of consolidation characteristics on CPT cone resistance and liquefaction resistance in silty soils
(Izmir Institute of Technology, 2013) Karaman, Mustafa; Ecemiş, Nurhan
One of the most important reasons of the life and property losses caused by earthquakes is liquefaction during or after the earthquakes. Many researches focused on liquefaction after the earthquakes have revealed that liquefaction occurs mostly in silty soils. Empirical relationships between normalized cone penetration resistance (qc1N), cyclic resistance ratio (CRR), magnitude of earthquake (Mw), and silt content (FC), derived from field observations, are currently used for liquefaction potential assessment of loose saturated sands and silty sands. However, the effects of fine content on liquefaction resistance and penetration resistance are not defined clearly in these researches. For this reason, it is aimed to investigate the effects of fine content on consolidation characteristics and the effects of coefficient of consolidation on liquefaction resistance and cone penetration resistance. In this study, a number of field and laboratory studies were carried out to investigate the existing relationships. According to the results of experimental studies, first, the effects of the fines content on coefficient of consolidation and drainage characteristics of soils for different soil density ranges are examined and it is established that, both the fines content and the relative density effect the coefficient of consolidation of the sands and silty sands. Second, the changes in cone penetration resistance are investigated for different range of fines content and the relative density which have significant influence on coefficient of consolidation. It has been realized that the coefficient of consolidation indicates a significant influence on the measured penetration resistance during penetration of the CPT cone to the soil having different relative density, and it is figured out that for stiff-dense to medium dense soil, the decrease of normalized cone resistance is observed due to the change in drainage characteristics of fines or coefficient of consolidation. On the other hand, for loose soils only the relative density indicates a significant influence on the measured CPT penetration resistance around the probe. Finally, the contribution of the relative density on the liquefaction resistance of soils is observed at different fines content and compared with the available method in the literature.
Investigation of liquefaction potential of sand-tire granulated rubber mixture that used around the buried pipes with shake table tests
(Izmir Institute of Technology, 2022-06) Karaman, Mustafa; Ecemiş Zeren, Nurhan
Liquefaction causes major deformations in infrastructures. The rapidly increasing of scrap car tires causes to find new areas to recycle them. It has been seen that granular rubbers to be an effective filling material with their density, permeability, compressibility and also damping characteristics for liquefaction remedation. Firstly, this study aims to explain the effect of rubbers mixed with sand on the liquefaction potential of the mixture during and after earthquakes. For this reason, one-dimensional shaking table experiments were carried out with granular rubbers-sand backfills in a large scale laminar box with varying rubber diameters and varying ratios of rubber. Secondly, the study aims to explain the effect of these mixtures on pipeline performance when used as filling around buried pipelines. Lastly, this study focuses on the possibility of rubber to contaminate groundwater with inorganics. For this purpose, a series of batch tests and column leaching tests were performed. Consequently, mixing rubbers with sand is effective in liquefaction remedation. They reduce the pore water pressure thanks to the high permeability, affect the consolidation characteristics with its permeability and compressibility, also reduce the earthquake loads with their damping facilities. In order to prevent the buried pipelines from uplifting during an earthquake, a limit criteria is suggested to design of the pipe diameter, burial depth and filling conditions with a predicted seismic load. Rubbers aren’t hazardous for contaminating the inorganics into groundwater. If granular rubbers are used in environmentally sensitive areas, it is recommended to use them after a prewash process or soaking in water for a day.