Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Artificial Neutral Networks To Predict Design Properties for Cemented Embankment Layers of High Speed Train Rail Ways(Foundation Cement, Lime, Concrete, 2013) Egeli, İsfendiyar; Tayfur, Gökmen; Yılmaz, E.; Uşun, HandanI. EGELI, G. TAYFUR, E. YILMAZ, H. USUN ARTIFICIAL NEURAL NETWORKS TO PREDICT DESIGN PROPERTIES FOR CEMENTED EMBANKMENT LAYERS OF HIGH SPEED TRAIN RAILWAYS Cement-Wapno-Beton, Vol. XVIII/LXXX, 2013, No 1, p. 10 High-speed train railway (HSTR) embankment is a complicated process, as it deals with high geometric design standards and material properties. In this study the replaceability of fill strata without cement prepared subgrade layer and with cement addition one is investigated. In the experiments the specimens composed of natural sand with different cement additions and two w/c ratios were used. The Plaxis-FEM (2D) program was employed to find the maximum expected total settlements of HSTR embankments with cemented subgrade layer. Furthermore, the artificial neural networks model was constructed to predict the failure stress, elasticity modulus and strains. The sensivity analysis has revealed that cement content was the most sensitive for stress and elasticity modulus predictions, while the curing age of specimens was for the strain forecast.Article Citation - WoS: 4Citation - Scopus: 3Designing High-Speed Train Railway Embankments Using Finite Element Analysis(Springer Verlag, 2012) Egeli, İsfendiyar; Usun, HandanDesign and construction of high-speed train railway (HSTR) infrastructure is different from that for normal trains, since high geometric standards and material properties are involved. For example, HSTR embankments are designed to limit total-differential settlements to minute amounts. In this study, a typical 'slab-track' type HSTR embankment was used to investigate the replaceability of one fill strata known as 'uncemented-prepared-subgrade layer' (U-PSL), constructed by using a locally obtained medium sand, as opposed to various 'cemented-prepared-subgrade layers' (C-PSL), whose mixes were prepared at two water-to-cement (w/c) ratios and three cement contents (c). Three size cylindrical samples were cast, 7-28 days water cured and were tested to obtain the unconfined compressive stresses, strains, elasticity moduli and Poisson's ratios at failure. Test results were then fed into the Plaxis-FEM program to find the maximum total settlements of individual layers and compared with the requirements. Only three C-PSL mixes having cement contents (c) of 20, 25, 30 % and water-to-cement (w/c) ratios of 0. 4 and 0. 5 met the strict settlement criteria. The study showed that the original (h = 2 m) thick U-PSL can be replaced with 0. 3h-m thick C-PSL at w/c = 0. 5 (i. e. h = 0. 6 m). Likewise, the original (h = 2 m) thick U-PSL can be replaced with 0. 2h-m thick C-PSL at w/c = 0. 4 (i. e. h = 0. 4 m). Also, the extra effort of doing in situ soil compaction and testing in layers is reduced or eliminated. This would give not only alternative ways to HSTR embankment designers/constructors, but also substantial savings in construction time and costs.Article Citation - WoS: 9Citation - Scopus: 9The Effect of Soil Mineralogy and Pore Fluid Chemistry on the Suction and Swelling Behavior of Soils(Springer Verlag, 2014) Pulat, Hasan Fırat; Yükselen Aksoy, Yeliz; Egeli, İsfendiyarSoil suction is one of the most important parameters for describing the moisture condition and engineering behavior of unsaturated soils. Therefore, changes in suction behavior of soils in the presence of saline waters are important for engineered barriers. The aim of this study was to determine the change in suction and swelling behavior of soils, which were exposed to salt solutions (NaCl, CaCl2, natural seawater) with respect to distilled water. The three soil samples were gathered with different mineralogy and plasticity characteristics and tested for determining matric and total suction values and for obtaining free swelling characteristics in the presence of salt solutions. The bentonitic soil sample had the highest total suction value in the presence of seawater. Kaolinitic and zeolitic soil samples had the highest total suction values in the presence of NaCl solution. The highest modified free swell index value of the samples was obtained in the presence of NaCl solution for all the soil samples. No relationship was found between the total suction, matric suction and the modified free swell index value of the tested soils.Article Citation - WoS: 37Citation - Scopus: 50Mechanism and Modelling of Shallow Soil Slope Stability During High Intensity and Short Duration Rainfall(Sharif University of Technology, 2011) Egeli, İsfendiyar; Pulat, Hasan FıratShallow landslides in nearly saturated uncohesive to slightly cohesive soils are triggered by high intensity, short duration rainfall which infiltrates into soil and changes intergranular friction and effective stresses. For this, the especially developed SoilWater Interaction Modelling System (SWIMS) was used with CL-ML type soils. For simplicity, rainfall intensity and duration were kept constant. Results showed that (1) All 35° slopes were failed by translational failure. For the other (15°,25°) slopes, no failures were observed; (2) For all slopes, FOS increased with increasing compaction degree and decreased with increasing slope angle; (3) Other parameters, such as soil density, porosity, saturation degree, water contents, and water permeability may also affect shear strength/slope stability, especially for low degrees of saturation (S<95%), compared to high degrees of saturation (S=,>95%). (4) A correlation of SWIMS tests observed that average wetting band depths ( hobser), with the calculated wetting band depths from the Lump Equation ( hLE), were poor, as hobser values were much higher than hLE values. Differences increased for very low degrees of saturation (S), compared to S>95%. This meant that the Lump equation underestimated wetting band depths. Further, if the Lump equation is still considered valid, this would imply either water-permeability increases, porosity decreases or both occur towards full saturation; a process where the last possibility is the most probable occurrence.