Numerical simulations of landslide-stabilizing piles: a remediation project in Söke,Turkey

A catastrophic landslide following a rainy season occurred in the backyard of a school building in Söke, Turkey. The landslide caused property damage and adversely affected the present forest cover. Immediately after the landslide, double-row stabilizing piles were designed and constructed based on the findings of two-dimensional (2D) finite element (FE) analyses to take an urgent precaution. To remedy the problem, pile displacements were monitored using inclinometers, and it was observed that the measured displacements were greater than the values calculated in the design stage. Accordingly, two different three-dimensional (3D) numerical FE models were used in tandem with the inclinometer data to determine the load transfer mechanism. In the first model, numerical analyses were made to predict the pile displacements, and while the model predicted successfully the displacement of the piles constructed in the middle with reasonable accuracy, it failed for the corner piles. In the second model, the soil load transfer between piles was determined considering the sliding mass geometry, the soil arching mechanism and the group interaction between adjacent piles. The results of the second model revealed that the middle piles with large displacements transferred their loads to the corner piles with smaller displacements. The generated soil loads, perpendicular to the sliding direction, restricted pile deformations and piles with less displacement were subjected to greater loads due to the bowl-shaped landslide. A good agreement between the computed pile displacements and inclinometer data indicates that the existing soil pressure theories should be improved considering the position of the pile in the sliding mass, the depth and deformation modulus of stationary soil, the relative movement between the soil and piles and the relative movement of adjacent piles.     

A study of gross alpha and beta measurements for thermal springs in Central Anatolia,Turkey

A screening of natural radioactivity content has been carried out in thermal water samples collected from surrounding of Central Anatolia, Turkey. The concentration levels of gross alpha and beta of 19 different samples has been determined using the low background gas-flow proportional counter. The measured gross alpha and beta activities in waters range from 0.11 to 16 Bq/L and 0.10 to 16.9 Bq/L, respectively. The measured values of gross alpha and beta concentrations are compared to previous studies in the literature and recommend WHO guideline activity concentration. The data resulting from the measurement have been statistically analyzed.     

The evolution of the Cappadocia Geothermal Province,Anatolia (Turkey): geochemical and geochronological evidence

Cappadocia Geothermal Province (CGP), central Turkey, consists of nine individual geothermal regions controlled by active regional fault systems. This paper examines the age dating of alteration minerals and the geochemistry (trace elements and isotopes) of the alteration minerals and geothermal waters, to assess the evolution of CGP in relation to regional tectonics. Ar–Ar age data of jarosite and alunite show that the host rocks were exposed to oxidizing conditions near the Earth’s surface at about 5.30 Ma. Based on the δ¹⁸O–δD relationhip, water samples had a high altitude meteoric origin. The δ³⁴S values of jarosite and alunite indicate that water samples from the southern part of the study area reached the surface after circulation through volcanic rocks, while northern samples had traveled to the surface after interacting with evaporates at greater depths. REY (rare earth elements and yttrium) diagrams of alteration minerals (especially illite, jarosite and alunite) from rock samples, taken from the same locations as the water samples, display a similar REY pattern to water samples. This suggests that thermal fluids, which reached the surface along a fault zone and caused the mineral alteration in the past, had similar chemical composition to the current geothermal water. The geothermal conceptual model, which defines a volcanically heated reservoir and cap rocks, suggests there are no structural drawbacks to the use of the CGP geothermal system as a resource. However, fluid is insufficient to drive the geothermal system as a result of scanty supply of meteoric water due to evaporation significantly exceeding rainfall.     

Determination of sediment deposition of Hasanlar Dam using bathymetric and remote sensing studies

Natural Hazards - Hasanlar Dam and Hydroelectric Power Plant are located on Küçük Melen Creek in the Western Black Sea Basin of Turkey. The dam was constructed in 1974 to provide...     

Nickel- und Kupfer-reiche Manganknollen der Tiefsee als Produkte frühdiagenetischer Vorgänge

Zusammenfassung Die Manganknollen in den Tiefseeregionen des Zentralpazifik variieren stark in ihrer chemischen Zusammensetzung, ihrem mineralogischen Aufbau und ihrer äußeren Gestalt. Das von uns untersuchte Probenmaterial stammt aus der abyssalen Hügelregion zwischen der Clarion- und. der Clipperton-Bruchzone. Während Fe-reiche, Ni- und Cu-arme Knollenmeist Polyknollen - in der näheren Umgebung und auf den Hängen von submarinen Bergen vorkommen, sind in den flachen Beckenbereichen Ni-, Cu- und Mn-reiche Knollen in den obersten 5 bis 15 cm (peneliquider Bereich) der pelagischen Sedimente verbreitet. Die Bergknollen (B-Typ-Knollen) wachsen durch Ausfällung von kolloidaler Substanz (Fe-Hydroxyd- und Mn-Oxidhydrat-Sol) aus dem bodennahen Meerwasser (hydrogenetisches Wachstum), die Sedimentknollen (A-Typ-Knollen) enstehen auf Grund einer frühdiagenetischen Mobilisation und Fraktionierung von Mn (Lösung als Mn²⁺ und Wiederausfällung durch Oxydation) und bei einem Zusatzangebot an Cu, Ni und Zn durch partielle oder vollkommene Auflösung von Sedimentbestandteilen. In den Sedimentknollen sind neben Todorokitschichten auch Mikrobereiche mit erhöhten Fe- und Si-Gehalten vorhanden, die röntgenamorphe bis schwach kristallisierte, ebenfalls frühdiagenetisch gebildete Eisensilikate (Nontronit) enthalten. Ein im Zentralpazifik sehr weit verbreiteter Knollentyp (diskoidale AB-Typ-Knollen) ist allerdings durch zwei Quellen gleichzeitig versorgt worden, d. h. diese Knollen wachsen an ihrer Unterseite auf Grund frühdiagenetischer und an ihrer Oberseite auf Grund hydrogenetischer Stoffzufuhr.

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Deep-sea ferromanganese nodules of the Central Pacific Ocean display a great range of variations in their chemical composition, mineralogical property and morphological feature. The nodule and sediment samples investigated by us were taken from the bottom of the abyssal hill region between the Clarion and the Clipperton Fracture Zone. Fe-rich, Ni- and Cu-poor nodules exist, mostly in the shape of polynodules, in the surroundings and on the slopes of seamounts and hills. In contrast to this Ni-, Cu- and Mn-rich nodules are distributed in the flat basin regions and have been accumulated within the uppermost 5 to 15 cm (peneliquid layer) of the pelagic sediment. The hill nodules (B-type nodules) grow by precipitation of colloidal phases (Fe-hydroxide and hydrated Mn-oxide) from the bottom-near sea water (hydrogenetic growth). The sediment nodules (A-type nodules) are formed from an early diagenatic mobilization and fractionating of Mn (dissolution as Mn²⁺ and reprecipitation by oxidation) receiving an additional supply of Cu, Ni, and Zn by partial or complete dissolution of sediment constituents. Within the sediment nodules exist besides the layers of Todorokite also microzones containing higher contents of Si and Fe; in this nodule substance early diagenetically formed iron silicates (nontronite) could be identified being in an X-ray amorphous to weakly crystallized state. A nodule type (discoidal AB-type nodules) being most frequently distributed in the Central Pacific have been supplied by two different sources more or less simultaneously, i. e. these nodules grow at the bottom side by an early diagenetical supply from the pore water and at the top side by a hydrogenetic supply from the bottom-near seawater.

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Résumé Les nodules de manganèse des régions abyssales du Pacifique Central présentent une grande diversité dans leur composition chimique, leur structure minéralogique et leur forme. Les échantillons que nous avons étudiés sont originaires de la région des collines abyssales entre les zones de fractures de Clarion et de Clipperton. Pendant que les nodules riches en Fe et pauvres en Ni et Cu — pour la plupart des polynodules — se trouvent dans le proche entourage et sur les versants des collines abyssales, les nodules riches en Ni, Cu et Mn sont fréquents dans les 5 à 15 cm supérieurs (zone pénéliquide) des sédiments pélagiques des parties plates des bassins. Les nodules des collines (nodules du type B) se forment par précipitation de substances colloidales (sols d'hydroxydes de Fe et d'oxyhydrates de Mn) de F eau de la mer proche du fond (croissance hydrogénée); les nodules sédimentaires (nodules du type A) se forment àpartir d'une mobilisation diagénétique hâtive et du fractionnement du Mn (solution comme Mn²⁺ et précipitation nouvelle par oxydation) et par une addition supplementaire de Cu, Ni et Zn à la suite d'une dissolution partielle ou complète de composants sédimentaires. Dans les nodules sédimentaires on trouve outre des couches de todorokrite des micro-domaines avec des teneurs élevés en Fe et Si qui contiennent des silicates ferreux (nontronite) amorphes à peu cristallisés, également formés au début de la diagénèse. Cependant un type de nodules (nodules discoidaux de type AB) très largement répandu dans le Pacifique Central sédimente à deux sources simultanées, à savoir par addition de substances à leur face inférieure au début de la diagenèse et par addition de substances hydrogénétiques à leur face supérieure.

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Depositional conditions of the coal-bearing Hirka Formation beneath Late Miocene explosive volcanic products in NW central Anatolia,Turkey

This work focuses on the relationship between the coal deposition and explosive volcanism of the Miocene basin, NW central Anatolia, Turkey. The coal-bearing Hirka Formation was deposited over the Galatian Andesitic Complex and/or massive lagoonal environments during the Miocene. The investigated lignite is a high ash (from 32 to 58%) and sulphur (from 1.43 to 3.03%) lignite which is petrographically characterised by a high humunite content. The mineral matter of the studied lignite samples is made up of mainly clay minerals (illite-smectite and kaolinite), plagioclase and quartz in Bolu coal field, clay minerals (illite-smectite, smectite and illite), quartz, calcite, plagioclase and gypsum in Seben coal field, quartz, K-feldspar, plagioclase and clay minerals (kaolinite and illite) in K?br?sc?k, and dolomite, quartz, clinoptilolite, opal CT and gypsum in Çaml?dere coal field. The differences in these four types of lignite with specific mineralogical patterns may be due to the explosive volcanic events and depositional conditions which changed from one coal field to the others. There is a zonation from SW to SE in the studied area for zeolites such as Opal CT+smectite-clinoptilolite-analcime-K-feldspar. Carbonate minerals are commonly calcite in Seben and K?br?sc?k coal fields. In Bolu, coal samples are devoid of calcite and dolomite. These analyses show that there is an increase in the amount of Mg and a decrease in the amount of Na from the northwestern part to the southern part in the study area.     

Stratigraphy and tectono-sedimentary evolution of the Upper Cretaceous–Tertiary sequence in the southern part of the Malatya Basin, East Anatolia, Turkey

The Malatya Basin is situated on the southern Taurus-Anatolian Platform. The southern part of the basin contains a sedimentary sequence which can be divided into four main units, each separated by an unconformity. From base to top, these are: (1) Permo-Carboniferous; (2) Upper Cretaceous–Lower Paleocene, (3) Middle-Upper Eocene and (4) Upper Miocene. The Upper Cretaceous–Tertiary sedimentary sequence resting on basement rocks is up to 700 m thick.The Permo-Carboniferous basement consist of dolomites and recrystallized limestones. The Upper Cretaceous–Lower Paleocene transgressive–regressive sequence shows a transition from terrestrial environments, via lagoonal to shallow-marine limestones to deep marine turbiditic sediments, followed upwards by shallow marine cherty limestones. The marine sediments contain planktic and benthic foraminifers indicating an upper Campanian, Maastrichtian and Danian age. The Middle-Upper Eocene is a transgressive–regressive sequence represented by terrestrial and lagoonal clastics, shallow-marine limestones and deep marine turbidites. The planktic and benthic foraminifers in the marine sediments indicate a Middle-Upper Eocene age. The upper Miocene sequence consists of a reddish-brown conglomerate–sandstone–mudstone alternation of alluvial and fluvial facies.During Late Cretaceous–Early Paleocene times, the Gündüzbey Group was deposited in the southern part of a fore-arc basin, simultaneously with volcanics belonging to the Yüksekova Group. During Middle-Late Eocene times, the Yeşilyurt Group was deposited in the northern part of the Maden Basin and the Helete volcanic arc. The Middle-Upper Eocene Malatya Basin was formed due to block faulting at the beginning of the Middle Eocene time. During the Late Paleocene–Early Eocene, and at the end of the Eocene, the study areas became continental due to the southward advance of nappe structures.The rock sequences in the southern part of the Malatya Basin may be divided into four tectonic units, from base to top: the lower allochthon, the upper allochthon, the parautochthon and autochthonous rock units.     

Free vibration of functionally graded beams resting on Winkler-Pasternak foundation

In the present study, the free vibration of functionally graded beams resting on two parameter elastic foundation was examined. The properties of the functionally graded materials were presumed to vary continuously along the thickness direction. The foundation medium was assumed to be linear, homogeneous, and isotropic, and it was modeled by the Winkler-Pasternak model with two parameters for describing the reaction of the elastic foundation on the beam. The functionally graded beam was modeled with classical beam theory. The governing equation including the effects of functionally graded material properties, Winkler-Pasternak elastic foundation was solved using separation of variables. The eigenvalues of yielding fundamental equation versus clamped-clamped, clamped-free, clamped-simply supported, and simply supported-simply supported boundary conditions were found. To corroborate the results, comparisons were carried out with available results for homogeneous and functionally graded beams. The effects of Winkler-Pasternak type elastic foundation and functionally graded material properties on the values of dimensionless frequency parameter of beams were discussed. Briefly, it was found that the dimensionless frequency parameters of beam change according to material properties, presence of elastic foundation, and boundary conditions; moreover, the separate effects of these quantities on each other are interesting.