Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Seismic Site Classification via Vs30 and SPT-N Values in Antakya City, Türkiye(Taylor & Francis Ltd, 2026-01-22) Alosman, Salama Omar; Akin, Muge K.; Cabalar, Ali FiratThe paper presents an assessment for the seismic site classification (SSC) in Antakya city located in southern central T & uuml;rkiye, strongly affected by three destructive earthquakes of 7.7 Mw took place in Pazarcik (Kahramanmaras) on February 6, 2023, 7.6 Mw took place in Elbistan (Kahramanmaras) on February 6, 2023, and 6.4 Mw took place in Defne (Hatay) on February 20, 2023. The V-S30 and SPT-N values have been used to identify the SSC in the region with respect to the provisions recommended by the National Earthquake Hazards Reduction Program (NEHRP), Design of Structures for Earthquake Resistance (Eurocode 8), and Turkish Building Earthquake Code (TBEC). The values of SPT-N were recorded from the field works that include 630 boreholes in the top 30 m, whilst the V-S30 was calculated through the multichannel analysis of surface waves (MASW) method performed at 977 different locations across the region. The results showed that approximately 51% and 44% of soils in the city of Antakya has been classified as Class C and Class D, respectively, in accordance with the NEHRP and TBEC, whilst 52% and 44% of the same region has been classified as Class B and Class C, respectively, in accordance with the Eurocode 8. Furthermore, a newly proposed correlation as well as already available ones between the V-S30 and SPT-N values have been presented comparatively by an extensive series of GIS maps produced in order to have a much clear understanding on the various soil types in Antakya. Evidently, the results of this research should be of a great significance for researchers and practitioners working on the earthquake-resistant structures, prediction of ground movements, and in seismic risk assessments.Article Sustainable Stabilization of Peat Soil with Hybrid Geopolymer Jet Grout Columns(Springer Int Publ A.G., 2025-10-15) Yalcin, Hakan; Erol, Aykut; Kaya, Zulkuf; Cadir, Cenk Cuma; Uncuoglu, Erdal; Akin, Muge K.Peat soils present severe challenges in geotechnical engineering due to their low shear strength, high water content, and aggressive chemical environments such as sulfate exposure. While cement-based jet grouting (JG) is widely used, it entails high carbon emissions and energy consumption. Hybrid geopolymer jet grout columns (HGJGCs) are presented in this work as a viable and sustainable alternative. Unlike conventional geopolymer studies that rely on pre-cured molds later exposed to aggressive environments, this research simulates realistic field conditions by injecting fresh geopolymer directly into sulfate-rich peat, where early-age durability and strength are critical. To address early strength limitations commonly seen in aggressive situations, a tiny amount of cement was added to the fly ash/GGBFS-based combination. Crucially, there is no need for high heat because the mechanism cures at room temperature. Physical model testing, laboratory-scale jet grouting, and performance comparisons with conventional JGCs were all carried out. Results show that HGJGCs increased the bearing capacity of peat by 5.5 times, improved compressive strength (5.3-5.7 MPa), and reduced settlement more effectively than JGCs. Additionally, CO2 emissions were reduced by 25.14% due to lower binder-related emissions and energy demand. This work shows that hybrid geopolymer systems are a viable, low-carbon substitute for peat stabilization because they can function well in real-world, chemically demanding situations.Article Citation - WoS: 16Citation - Scopus: 18Impact of Jet-Grouting Pressure on the Strength and Deformation Characteristics of Sandy and Clayey Soils in the Compression Zone(Korean Society of Civil Engineers-ksce, 2019-08) Akin, Mutluhan; Akkaya, Ismail; Akin, Muge K.; Ozvan, Ali; Ak, YusufJet-grouting as a soil improvement method is extensively preferred in today's civil engineering practice. High-modulus grout columns constructed by extremely high jetting pressures displace the surrounding soil causing a densification in soil particles. Accordingly, the strength as well as the deformation characteristics of subsurface soils are relatively improved across the compression zone which is under the influence of high jetting pressure. In this study, the modification of soil properties in compression zone after jet-grouting in sandy and clayey soils is investigated by standard penetration tests (SPT) and multi-channel analysis of surface waves (MASW) performed at a couple of construction sites along established jet-grout column rows. The in-situ test results point out significant improvement of the measured parameters compared to initial values. The rate of enhancement in the compression zone is higher in sandy strata than that of clayey deposits. The strengthening of soil due to jetting pressure is validated by finite element analyses as well. Furthermore, very low shear strain values are obtained in clayey soils with respect to the improved characteristics of compression zone representing extremely low shear deformation under foundation.Article Citation - WoS: 14Citation - Scopus: 14Experimental Studies on the Physico-Mechanical Properties of Jet-Grout Columns in Sandy and Silty Soils(Pergamon-Elsevier Science Ltd, 2016-04) Akin, Muge K.The term of ground improvement states to the modification of the engineering properties of soils. Jet grouting is one of the grouting methods among various ground improvement techniques. During jet grouting, different textures of columns can be obtained depending on the characteristics of surrounding subsoil as well as the adopted jet-grouting system for each site is variable. In addition to textural properties, strength and index parameters of jet-grout columns are highly affected by the adjacent soil. In this study, the physical and mechanical properties of jet-grout columns constructed at two different sites in silty and sandy soil conditions were determined by laboratory tests. A number of statistical relationships between physical and mechanical properties of soilcrete were established in this study in order to investigate the dependency of numerous variables. The relationship between q(u) and gamma(d) is more reliable for sandy soilcrete than that of silty columns considering the determination coefficients. Positive linear relationships between Vp and gamma(d) with significantly high determination coefficients were obtained for the jet-grout columns in silt and sand. The regression analyses indicate that the P-wave velocity is a very dominant parameter for the estimation of physical and mechanical properties of jet-grout columns and should be involved during the quality control of soilcrete material despite the intensive use of uniaxial compressive strength test. Besides, it is concluded that the dry unit weight of jet-grout column is a good indicator of the efficiency of employed operational parameters during jet-grouting. (C) 2016 Elsevier Ltd. All rights reserved.Conference Object Evaluation of the Performance of Geotextiles Using Finite Element Analysis in the Settlement Results: A Case Study in Kayseri, Turkey(Korean Geosynthetics Society, 2018) Yalçın, Hakan; Akin, Muge K.; Çabalar, Ali FiratGeotextiles are successfully designated for the reinforcement of soils to solve certain settlement as well as bearing capacity problems in difficult ground conditions. Furthermore, geotextiles are used for the stability of man-made slopes. In this study, the performance of geotextiles for soil improvement is evaluated by considering various geotextile types that have different axial stiffness values. The stiffness values are compared using a finite element method (FEM) based software PLAXIS 2D. As case study, Kayseri Organized Industrial Site in Turkey was chosen for the comparison of these geotextiles for a specific soil profile during analyses. Besides, the FEM based approach is also considered for the settlement, axial force and the effective stress changes during the application of geotextiles. The selected geotextiles are also correlated using scanning electron microscope (SEM) analyses. The results indicated that the axial stiffness (EA) can be considered with the effect on the possible soil settlement and axial force values. The settlement values reduced with increase in stiffness of reinforcement. © 2021 Elsevier B.V., All rights reserved.Article Citation - WoS: 15Citation - Scopus: 18Evaluation of Seismic Site Classification for Kahramanmaras City, Turkey(Springer, 2021-01-28) Naji, Dalia Munaff; Akin, Muge K.; Cabalar, Ali FiratThis paper presents a study on the seismic site classification map using the geophysical tests in Kahramanmaras city located at a place where African, Anatolian, and Arabian plates meeting in southern-central Turkey. Generating seismic site classification maps in accordance with National Earthquake Hazards Reduction Program (NEHRP) has become a more significant criterion for earthquake hazard estimations. The SPT-N values obtained from the field studies at 287 boreholes within the upper 30 m were used to describe the subsurface conditions in the region. The shear wave velocity (V-S) values in the study area were obtained by implementing Multichannel Analysis of Surface Waves (MASW) and Microtremor Array Method (MAM) measurements tests. An approach proposed by Boore (Boore, Bull Seismol Soc Am 94:591-597, 2004) for the cases where the V-S measurements do not reach 30 m depth has also been adopted by correlating the shallow shear wave velocity with V-S30. The resulting site classification maps estimate that the study area is predominantly classified as soil site class C, while the small areas were rarely classified as soil site class D and B. Furthermore, a systematic analysis based on a comparative study of the present research and the published correlations for seismic site classification with V-S30 values has been carried out using Geographical Information System (GIS). Evidently, the V-S30 based seismic site classification maps could be effectively used by researchers and engineers for the purpose of land-use planning and urban development in earthquake-prone regions.Article Citation - WoS: 14Citation - Scopus: 16Dynamic Soil Characterization and Site Response Estimation for Erbaa, Tokat (Turkey)(Springer, 2016-03-11) Akin, Muge K.; Kramer, Steven L.; Topal, TamerSite amplification is one of the most important factors controlling damage in urban areas through strong earthquakes. Local site effects play an important role in earthquake-resistant design and should be considered for site response analyses. In this study, ground response analyses in Erbaa, Turkey, a settlement in the North Anatolian Fault Zone, using one-dimensional equivalent linear analysis and empirical approaches based on shear wave velocity profiles are evaluated and compared. The ground response analyses were performed with consideration of shear wave velocity, and modulus reduction and damping behavior for different confining pressure and plasticity index-dependent models. The results of ground response analyses and amplification values from empirical equations using shear wave velocity are illustrated in terms of amplification and predominant period maps of the seismically active Erbaa settlement area. The comparison has been made in these produced maps of the study area in order to evaluate different site response analyses.Article Citation - WoS: 15Citation - Scopus: 15Comparison of SPT and VS-Based Liquefaction Analyses: A Case Study in Ercis (Van, Turkey)(Springer International Publishing AG, 2017-12-08) Akkaya, Ismail; Ozvan, Ali; Akin, Mutluhan; Akin, Muge K.; Ovun, UgurLiquefaction which is one of the most destructive ground deformations occurs during an earthquake in saturated or partially saturated silty and sandy soils, which may cause serious damages such as settlement and tilting of structures due to shear strength loss of soils. Standard (SPT) and cone (CPT) penetration tests as well as the shear wave velocity (V-s)-based methods are commonly used for the determination of liquefaction potential. In this research, it was aimed to compare the SPT and V-s-based liquefaction analysis methods by generating different earthquake scenarios. Accordingly, the Ercis residential area, which was mostly affected by the 2011 Van earthquake (M-w = 7.1), was chosen as the model site. Ercis (Van, Turkey) and its surroundings settle on an alluvial plain which consists of silty and sandy layers with shallow groundwater level. Moreover, Caldiran, Ercis-Kocapinar and Van Fault Zones are the major seismic sources of the region which have a significant potential of producing large magnitude earthquakes. After liquefaction assessments, the liquefaction potential in the western part of the region and in the coastal regions nearby the Lake Van is found to be higher than the other locations. Thus, it can be stated that the soil tightness and groundwater level dominantly control the liquefaction potential. In addition, the lateral spreading and sand boiling spots observed after the 23rd October 2011 Van earthquake overlap the scenario boundaries predicted in this study. Eventually, the use of V-s-based liquefaction analysis in collaboration with the SPT results is quite advantageous to assess the rate of liquefaction in a specific area.Article Citation - WoS: 30Citation - Scopus: 33Assessment of the Effectiveness of a Rockfall Ditch Through 3-D Probabilistic Rockfall Simulations and Automated Image Processing(Elsevier, 2021-03) Akin, Mutluhan; Dincer, Ismail; Ok, Ali Ozgun; Orhan, Ahmet; Akin, Muge K.; Topal, TamerRockfall ditches or catchment areas aim to collect falling blocks at the toe of a source zone by dissipating the energy of blocks in an excavated trench. The effectiveness of a rockfall ditch is simply expressed by its block catchment performance and can be evaluated by empirically using existing design charts as well as rockfall simulations. Although 2-dimensional (2-D) analysis has been executed to assess the catchment ditch effectiveness in engineering practice, 3-dimensional (3-D) rockfall models have not received enough attention so far. In this study, the effectiveness of a considerably long rockfall ditch to protect a settlement from falling rocks was assessed on the basis of 3-D rockfall analyses executed using high-resolution digital surface models. The rockfall ditch efficiency was found to be moderate to limited for various segments considering the percentage of blocks not trapped by the ditch. Moreover, the sensitivity of ditch efficiency to ditch depth was analyzed by automated image processing method as well. Additionally, a particular section of ditch alignment was fictitiously excavated or filled by synthetic Digital Surface Model (DSM) generation through image processing. 3-D rockfall modeling carried out using the DSMs with synthetically manipulated ditches points out that the effectiveness of a catchment ditch is highly depended upon ditch depth. Even a small volume of block accumulation inside the ditch definitely reduces the ditch performance resulting extended runout distances reaching to residential area. Finally, 3-D rockfall modeling is accepted to be an effective tool to rate the efficiency of existing rockfall ditches and synthetically generated ditches on DSMs (or DEMs) by means of automated image processing method may assist the control of current ditch dimension as well as new catchment ditch design.Article Citation - WoS: 2Citation - Scopus: 4A Study of the Relationship Between the Pressuremeter Modulus and the Preconsolidation Pressure Around a Thrust Fault(Springer, 2019-10) Ozvan, Ali; Ozvan, Elif E.; Akkaya, Ismail; Akin, Mutluhan; Akin, Muge K.The study area is in a zone under the influence of the Lake Van water changes and the Van fault, which caused a destructive earthquake in 2011. Due to the level changes of Lake Van, sediments with different thicknesses as well as grain sizes were deposited in this region and the characteristics of these sediments were significantly affected by the morphology and lake water fluctuations in the past. A total of six boreholes were drilled along a 3-km line within the study area to determine the preconsolidation pressure (sigma(pc)) and the pressuremeter test values of the clayey levels of old lake deposits-which are known to have different physical and mechanical properties-with hopes to gain an insight on how they influence the mechanical tests performed in the field and in laboratory conditions. The relationship between these values was also statistically evaluated. When both datasets were evaluated together, it was determined that the stresses in the area close to the Van Thrust Fault plane caused deformations in the soil, which in turn affected the hanging-wall block of the thrust fault in particular. The inspection of E-M and sigma(pc) values for the area within the primary compression zone of the Van Fault revealed that both values of the boreholes on the footwall block were higher compared to other boreholes close to the lake (southwest). This finding indicates that the fault stresses at the footwall block of the fault plane enhance the mechanical characteristics of the soil. The data obtained were also evaluated using regression analysis. Relationships between all available data were investigated and a high coefficient of determination was derived between the Menard deformation modulus (E-M) and the preconsolidation (sigma(pc)) pressure.