Çevrimsel yükleme, boşluk suyu basınçlarında artışlar meydana getirerek, daha sonra sıvılaşma ve oturmalara yol açabilmektedir. Yakın zamanda yapılan çalışmalarda, boşluk suyu basıncının ilksel çevre ...basıncına eşit olması durumunda, çevrimsel gerilme oranı ve zeminin izafi sıkılığının aşırı boşluk suyu basıncının gelişiminde büyük rolü olduğu vurgulanmaktadır. Bununla birlikte, boşluk suyu basıncı aynı zamanda eksenel deformasyonun bir fonksiyonudur. Bu bağlamda, plastik olmayan bir silt zeminin boşluk suyu basıncı gelişim davranışının değerlendirilebilmesi için bir dizi çevrimsel üç eksenli basınç deneyi yapılmıştır. Deneyler ile, boşluk suyu basıncı, çift genlikli eksenel deformayon ve çevrim sayısının çevrimsel gerilme oranına bağımlılığı araştırılmıştır. Bu amaçla, suya doygun örnekler üzerinde gerilme kontrollü çevrimsel üç eksenli basınç deneyleri 0.1 Hz frekansta ve 100 kPa çevre basıncında tatbik edilmiştir. Sıvılaşmaya neden olan çevrim sayısının, artan çevrimsel gerilme oranı ve izafi sıkılık ile azaldığı elde olunmuştur. Çalışmada elde edilen veriler, plastik olmayan silt zeminin boşluk suyu basıncı gelişim davranışıbı detaylarlandırmaktadır ve pratik amaçlarla kullanılabilir.
Çevrimsel yükleme, boşluk suyu basınçlarında artışlar meydana getirerek, daha sonra sıvılaşma ve oturmalara yol açabilmektedir. Yakın zamanda yapılan çalışmalarda, boşluk suyu basıncının ilksel çevre ...basıncına eşit olması durumunda, çevrimsel gerilme oranı ve zeminin izafi sıkılığının aşırı boşluk suyu basıncının gelişiminde büyük rolü olduğu vurgulanmaktadır. Bununla birlikte, boşluk suyu basıncı aynı zamanda eksenel deformasyonun bir fonksiyonudur. Bu bağlamda, plastik olmayan bir silt zeminin boşluk suyu basıncı gelişim davranışının değerlendirilebilmesi için bir dizi çevrimsel üç eksenli basınç deneyi yapılmıştır. Deneyler ile, boşluk suyu basıncı, çift genlikli eksenel deformayon ve çevrim sayısının çevrimsel gerilme oranına bağımlılığı araştırılmıştır. Bu amaçla, suya doygun örnekler üzerinde gerilme kontrollü çevrimsel üç eksenli basınç deneyleri 0.1 Hz frekansta ve 100 kPa çevre basıncında tatbik edilmiştir. Sıvılaşmaya neden olan çevrim sayısının, artan çevrimsel gerilme oranı ve izafi sıkılık ile azaldığı elde olunmuştur. Çalışmada elde edilen veriler, plastik olmayan silt zeminin boşluk suyu basıncı gelişim davranışıbı detaylarlandırmaktadır ve pratik amaçlarla kullanılabilir.
In this paper, a comparative experimental study was carried out to evaluate the effect of inclusion of different fiber types on strength of lime-stabilized clay. In this scope, a series of unconfined ...compressive strength tests were carried out on specimens including basalt and polypropylene fiber compacted under Standard Proctor effort (i.e., 35% by weight of soil). The effects of curing period (1, 7, 28, and 90 days), fiber type (basalt and polypropylene), fiber content (0, 0.25, 0.5, 0.75, 1%), fiber length (6, 12, and 19 mm), and lime content (0 and 9%) on strength properties were investigated. The results revealed that both basalt and polypropylene fibers increased the strength without inclusion of lime. For specimens including lime, strength of polypropylene fiber-reinforced specimens was remarkably higher than that reinforced with basalt fiber for lime-stabilized clay. However, greatest strength improvement was obtained by use of 0.75% basalt fiber of 19 mm length with 9% lime content after 90-day curing. Additionally, results of strength tests on specimens including 3 and 6% lime and 12-mm basalt fiber after 1, 7, 28, and 90-day curing were presented. It is evident that the use of 6-mm basalt fiber and 12-mm polypropylene fiber were the best options; however, efficiency of fiber inclusion is subject to change by varying lime contents. It was also observed that the secant modulus was increased by use of lime; however, strength of the correlations among secant modulus and unconfined compressive strength values was decreased by increasing amount of lime for specimens including both basalt and polypropylene fibers.
On October 30, 2020 14:51 (UTC), a moment magnitude (M) 7.0 (USGS, EMSC) earthquake occurred in the Aegean Sea. This paper presents the reconnaissance findings regarding the site effects on recorded ...strong ground motion intensities and duration, along with the resulting induced-structural damage in Izmir Bay and Samos Island, respectively. In all rock records, relatively high intensity long period rock spectral accelerations were observed in the mid to long period range of 0.5–1.5 s, which are attributed to the source, more specifically, to the slower rupture-mechanism of the event. These rich spectral intensities were further amplified by soil site effects and soil-superstructure resonance, leading to two to six times amplified overall responses and prolonged seismic shaking durations, more pronounced in Bayrakli and other Izmir Bay sites in Turkey. However, these amplified and prolonged excitations are still below design basis earthquake levels, which addresses the lack of proper structural design and construction deficiencies, as the underlying causes for the collapse to heavy damage performance of 795 buildings. On the other hand, although located only about 10 km from the rupture (22 km from the epicenter) and within the near fault zone, the town of Vathy on Samos Island (Greece) was rather lightly affected by the earthquake, with relatively few collapsed or heavily damaged buildings, partially attributed to the low height/low weight of structures in the area. However, a concentration of damage in low-rise buildings in Ano Vathy hill is considered indicative of a combination of coupled valley and topography effects on the strong motion. This event once again addressed the need to develop region-specific zonation and provisions, when more general code practices are proven to be inadequate to assess these extreme site effects.
The effects of freeze–thaw processes on a natural silt soil stabilized with Class C fly ash and cement are investigated in this study. The silt was obtained from Soma near the city of Izmir, Turkey. ...The experimental study consisted of stabilizing the cylindrical soil specimens with fly ash and cement at various rates by compacting and then curing these specimens up to 28 days in a moist room at a constant temperature and controlled humidity. Specimens were separated into two groups: half of them were protected by a stretch film to prevent desiccation; the remaining were unprotected. After curing, specimens were subjected to a maximum of seven cycles of closed-system freezing and thawing. Then, unconfined compressive strength (UCS) tests were conducted on all specimens and the results were evaluated in terms of the amount of cementitious material included, curing conditions and the number of cycles. As a consequence, it was noted that specimens of high fly ash and cement content had greater strength values.
This paper presents an investigation into the stabilization of a soft clay subgrade of a military zone in Izmir, Turkey with a very high lime fly ash. Zero%, 5%, 10%, 15% and 20% (m/m) of the soil ...was replaced with fly ash. In addition to the control specimen, four different stabilized soil samples were prepared mixing fly ash with soil at optimum water contents determined by standard proctor test. Experiments lasted for 3 months and the unconfined compressive strength and shear strength parameters, cohesion and internal friction angle, were determined after 1, 7, 28 and 90 days. It was found that, inclusion of fly ash improved the properties of the soil. The improvements, appearing with increasing fly-ash content, were attributed to the pozzolanic reaction and pore refinement effect of fly ash as well as its high free-lime content.
On October 30, 2020 14:51 (UTC), a moment magnitude (M
w
) of 7.0 (USGS, EMSC) earthquake occurred in the Aegean Sea north of the island of Samos, Greece. Turkish and Hellenic geotechnical ...reconnaissance teams were deployed immediately after the event and their findings are documented herein. The predominantly observed failure mechanism was that of earthquake-induced liquefaction and its associated impacts. Such failures are presented and discussed together with a preliminary assessment of the performance of building foundations, slopes and deep excavations, retaining structures and quay walls. On the Anatolian side (Turkey), and with the exception of the Izmir-Bayrakli region where significant site effects were observed, no major geotechnical effects were observed in the form of foundation failures, surface manifestation of liquefaction and lateral soil spreading, rock falls/landslides, failures of deep excavations, retaining structures, quay walls, and subway tunnels. In Samos (Greece), evidence of liquefaction, lateral spreading and damage to quay walls in ports were observed on the northern side of the island. Despite the proximity to the fault (about 10 km), the amplitude and the duration of shaking, the associated liquefaction phenomena were not pervasive. It is further unclear whether the damage to quay walls was due to liquefaction of the underlying soil, or merely due to the inertia of those structures, in conjunction with the presence of soft (yet not necessarily liquefied) foundation soil. A number of rockfalls/landslides were observed but the relevant phenomena were not particularly severe. Similar to the Anatolian side, no failures of engineered retaining structures and major infrastructure such as dams, bridges, viaducts, tunnels were observed in the island of Samos which can be mostly attributed to the lack of such infrastructure.
In this research, several models were developed to forecast the daily mean indoor temperature (IT) and relative humidity values in an education building in Izmir, Turkey. The city is located at a ...hot–humid climatic region. In order to forecast the IT and internal relative humidity (IRH) parameters in the building, a number of artificial neural networks (ANN) models were trained and tested with a dataset including outdoor climatic conditions, day of year and indoor thermal comfort parameters. The indoor thermal comfort parameters, namely, IT and IRH values between 6 June and 21 September 2009 were collected via HOBO data logger. Fraction of variance (R2) and root-mean squared error values calculated by the use of the outputs of different ANN architectures were compared. Moreover, several multiple regression models were developed to question their performance in comparison with those of ANNs. The results showed that an ANN model trained with inconsiderable amount of data was successful in the prediction of IT and IRH parameters in education buildings. It should be emphasized that this model can be benefited in the prediction of indoor thermal comfort conditions, energy requirements, and heating, ventilating and air conditioning system size.
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