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https://hdl.handle.net/20.500.12451/311

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Travertenlerin donma-çözülme döngüsü sonrasındaki tek eksenli basınç dayanımı kaybının fiziko-mekanik parametreler kullanılarak tahmin edilmesi
(Kırıkkale Üniversitesi, 2024) Mutlu, Mert; Kalkan, Murat
Doğal taşların inşaat sektöründe bir yapı malzemesi olarak kullanımı günden güne bir artış trendi içerisindedir. Travertenin yapısı gereği dayanıklı olması, aşınmaya karşı dirençli olması, ucuz olması, kolay işlenebilmesi ve hafif olması nedeniyle diğer doğal taşlara göre iç ve dış kaplamalarda kullanılabilirliği daha fazladır. Özellikle zorlu atmosferik koşullara sahip soğuk bölgelerde bu taşların dayanıklılığın belirlenebilmesi için donma-çözülme testinin yapılması gerekmektedir. Yapılan bu test sonucu eğer bir doğal taşın tek eksenli basınç dayanımı değeri kaybı %20’den fazla ise bu malzemenin yapı sektöründe kullanılması tavsiye edilmemektedir. Yapılan bu çalışmada Denizli travertenleri için literatürdeki çeşitli fiziko-mekanik parametreler kullanılarak kurulan çoklu regresyon modeliyle bu değer kaybı oranının donma-çözme deneyi yapmadan tahmin edilmesi amaçlanmıştır. Çoklu regresyon analizi tekniği olarak geriye doğru eleme tekniği tercih edilmiştir. Model denkleminin güvenilirlik değeri (R^2) 0,98 olarak hesaplanmış olup, oldukça yüksektir. Çalışma kapsamında geliştirilen bu model, araştırmacılara Denizli bölgesi travertenlerinin donma-çözülme testi yapmadan tek eksenli basınç dayanımındaki kaybın önceden kolayca, minimum maliyetle kestirebilmesi açısından çok yararlı olacaktır.
A novel risk assessment approach for open-cast coal mines using hybrid MCDM models with interval type-2 fuzzy sets: a case study in Türkiye
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Mutlu, Mert; Çetin, Nazlı Ceren; Önder, Seyhan
Mining is a high-risk industry where occupational accidents are common due to its complex nature. Therefore, providing a more holistic and dynamic risk assessment framework is essential to identify and minimize the potential risks and enhance safety measures. Unfortunately, traditional risk assessment methods have limitations and shortcomings, such as uncertainty, differences in experience backgrounds, and insufficiency to articulate the opinions of experts. In this paper, a novel risk assessment method precisely for such cases in the mining sector is proposed, applied, and compared with traditional methods. The objective of this study is to determine the risk scores of Turkish Coal Enterprises, based on non-fatal occupational accidents, which operates eight large-scale open-cast coal mine enterprises in Türkiye. The causes of the accidents were categorized into 25 sub-criteria under 6 main criteria. The risk scores for these criteria were computed using the Pythagorean fuzzy Analytical Hierarchy Process (PFAHP) method. The first shift (8–16 h) (0.6341) for the shift category is ranked highest out of the 25 sub-risk factors, followed by maintenance personnel (0.5633) for the occupation category; the open-cast mining area (0.5524) for the area category, the 45–57 age range (0.5279) for employee age category, and the mining machine (0.4247) for the reason category, respectively. The methodologies proposed in this study not only identify the most important risk factors in enterprises, but also provide a mechanism for risk-based rankings of enterprises by their calculated risk scores. The enterprises were risk-based ranked with the fuzzy Technique for Order Preference by Similarity to Ideal Solution (FTOPSIS) method and Paksoy approach based on interval type-2 fuzzy sets (IT2FSs). The findings indicate that the first three risk score rankings of enterprises are the same for both approaches. To examine the consistency of the applied methods, sensitivity analyses were performed. The results of the study also indicate that the proposed approaches are recommended for effective use in the mining sector due to their ease of application compared to other methods and their dynamic nature in the risk assessment process.
Estimating the noise-induced hearing losses under fuzzy environment
(Eskişehir Osmangazi Üniversitesi, 2023) Mutlu, Mert
Noise causes many negative effects both in our daily life and working life, reduces our quality of life, and affects our mental health directly or indirectly. The most common consequence of noise exposure is especially permanent hearing loss called noise-induced hearing loss (NIHL). NIHL is very prevalent in almost every stage of the mining industry. Therefore, the assessment of noise levels of mining operations and the estimation of NIHLs of employees is an important issue to prevent and minimize them. This study is aimed to the modeling of NIHL prediction at a quarry located in Aksaray, Turkey. Initially, noise levels were measured with a sound level meter for employees working in different positions for the quarry, and daily exposure levels (Lex,8h) were determined. Audiometry tests were also performed on all employees and NIHLs were evaluated and determined by an audiometrist. According to the results, 5 employees had NIHL in this enterprise. A fuzzy inference system (FIS)-based NIHL estimating model implemented on fuzzy logic using the Sugeno inference mechanism was developed. The model predicts NIHLs for given occupation, age, experience, and Lex,8h parameters. To determine the accurate prediction ability of the model, field noise measurements and audiometry test results data were used. The obtained results indicated that the model has accurate a prediction ability with a 94% success rate. This study proposes a method with high predictive ability using fuzzy sets theory, and will be a guide for the top management in considering the damage effects of noise in enterprises.
Evaluating rockfalls at a historical settlement in the Ihlara Valley (Cappadocia, Turkey) using kinematic, numerical, 2D trajectory, and risk rating methods
(Science Press, 2022) Sarı, Mehmet
Rockfalls are one of the most dangerous natural events in hilly terrains, and they substantially threaten residential areas and transport corridors in these environments. This study is aimed to analyze the risk of rockfall from a slope to nearby houses in a historical settlement with past rockfall histories. It contains numerous applications to study rockfall danger from different points of view (e.g., kinematics, numerical stability analysis, risk assessment, 2D trajectory). The rockfall kinematics revealed the statistics for different structurally controlled failure modes among the surveyed slope discontinuities, especially wedge type and block toppling were the most significant ones. Finite element analysis showed that the slope was stable under the natural condition with a safety factor of 2.19. The rockfall risk rating system calculated a medium risk for the houses downstream. Based on the field measurements, a possible rockfall profile was determined and located as an input in the 2D rockfall trajectory program. The rigid-body impact model runs utilized various shapes and sizes of blocks to simulate the rockfall events realistically. According to the 2D trajectory model results, there was no rockfall danger for the investigated downslope houses. The study showed the importance of using different analysis techniques to solve rockfall risk in protected areas based on scientific and rational approaches.
Stochastic assessment of rockburst potential in underground spaces using Monte Carlo simulation
(Springer, 2022) Kadkhodaei, Mohammad Hossein; Ghasemi, Ebrahim; Sarı, Mehmet
Rockburst (RB) is known as one of the deadliest and most destructive geotechnical events in deep underground spaces under high stresses. The complexity of the RB phenomenon and uncertainty arising from variability in geotechnical and geomechanical conditions makes its prediction very difficult. The current study is an attempt to address the suitability of the stochastic modeling approach for the evaluation of RB potential and to assess the effects of the contributing parameters on the phenomenon. To do this study, a database containing the major effective parameters on RB potential (i.e. stress concentration coefficient, brittleness coefficient, and elastic energy index) compiled from 335 case histories of RB in various underground projects worldwide was applied. Using this database, first, a new deterministic mathematical relation for predicting RB potential was developed using gene expression programming (GEP) method. Then, the RB phenomenon was simulated by the Monte Carlo (MC) method. The results reveal that stochastic modeling is a good means for modeling and evaluating the effects of the variability of contributing parameters on RB. Finally, sensitivity analysis was conducted to analyse the effects of the contributing parameters on RB potential. Sensitivity analysis showed that stress concentration coefficient, brittleness coefficient, and elastic energy index have a direct relationship with RB potential. Furthermore, the elastic energy index was found to be the most effective parameter on the RB potential with regression coefficient of + 0.50.
Two- and three-dimensional stability analysis of underground storage caverns in soft rock (Cappadocia, Turkey) by finite element method
(Science Press, 2022) Sarı, Mehmet
ngineering design in soft rocks and its stability analysis exerts many challenges to rock engineers. Many engineering works in Turkey's Cappadocia region must face and tackle the existing sites covered by the soft rocks. This study is aimed to examine the stability condition of a typical underground storage cavern (USC) excavated in a soft rock in this region. For this purpose, two- and three-dimensional stability analyses of the USCs were performed using the finite element method (FEM). Because of the inherent difficulty in characterizing soft/weak rock masses in the region using traditional classification systems, the stability of a typical USC was evaluated by representing the rock mass condition with two distinct scenarios in FEM analysis. While these structures were unstable according to the 2D analysis conducted in RS2 software in the worst-case scenario, they were stable in the 3D analysis using RS3 software in both scenarios. Besides, feasible cover depths were examined to assess their possible effects on the factor of safety and deformation measurements. It was found that 15 m seems to be an optimal depth for excavating a typical USC in the soft rocks exposed in the region. The 3D FEM results provide valuable information to optimize the future planning and preliminary design of USCs.
Determination of representative elementary volume (REV) for jointed rock masses exhibiting scale-dependent behavior: a numerical investigation
(Springer, 2021) Sarı, Mehmet
Representative elementary volume (REV) is defined as the usual size of a rock mass structure beyond which its mechanical properties are homogenous and isotropic, and its behavior can be modeled using the equivalent continuum approach. Determination of REV is a complex problem in rock engineering due to its definition ambiguity and application area. This study is one of the first attempts to define a REV for jointed rock masses using the equivalent continuum approach. It is aimed to numerically search a ratio between the characteristic size of an engineering structure and pre-existing joint spacing, which are the two most important contributing elements in assessing REV. For this purpose, four hypothetical engineering cases were investigated using the RS2 (Phase2 v. 9.0) finite element (FE) analysis program. An underground circular opening with a constant diameter, an open-pit mine with varying bench heights, a single bench with a constant height, and an underground powerhouse cavern with a known dimension were executed for possible changes in the safety factor and total displacement measurements under several joint spacing values. Different cut-off REVs were calculated for FE models depending on the type of excavation and measurement method. An average REV size of 19.0, ranging between a minimum of 2 for tunnels and a maximum of 48 for slopes, was found in numerical analysis. The calculated sizes of REV were significantly larger than the range of values (5 to 10) commonly reported in the relevant geotechnical literature.
Secondary toppling failure analysis and optimal support design for ignimbrites in the Ihlara Valley (Cappadocia, Turkey) by finite element method (FEM)
(Springer, 2021) Sarı, Mehmet
Kizilkaya ignimbrite, characterized by a blocky structure in the Ihlara Valley (Cappadocia, Turkey), poses many hazards to visitors and the human-made churches and dwellings carved in the valley slopes. The instability mechanism in the valley should be carefully investigated to determine and implement a suitable prevention method. For this purpose, the finite element method (FEM) models were developed in RS2 software to illustrate the problem of progressive failure in the valley's cliffs. A simple geometry represented the rock strata and its surroundings. The effect of columnar structure on the cliff stability was mimicked as a jointed medium in two-dimensional numerical models. The results of FEM models revealed that as the stage of failure progresses in the slope, the strength reduction factor decreased subsequently from 2.05 to 0.45. These models correctly captured the prevailing failure mechanisms observed in the valley slopes. Depending on the size of the rock blocks described in the FEM analysis, an effective support system was proposed to remedy the slope failure. It was found that fully bonded rock bolts with a length of at least 2.5 times the width of a typical block should be implemented with a certain grid pattern. The study clearly showed that it was promising to realize a numerical solution to secondary toppling failure in a jointed rock mass using the FEM.
Niğde yöresi kırmataş ocaklarında kayaçların fiziksel ve mekanik özelliklerinin hidrolik kırıcı performansına etkisi
(TMMOB Maden Mühendisleri Odası, 2020) Sarı, Mehmet; Yılmaz, Tevhit; Çomaklı, Ramazan
Bu çalışmada, Niğde ilinde faaliyet gösteren yedi farklı kırmataş ocağında delme-patlatma sonrası oluşan yığındaki iri blokların (patar) ufaltılmasında kullanılan hidrolik kırıcıların performansına kayaçların fiziksel ve mekanik özelliklerinin etkileri araştırılmıştır. Bu amaçla, yığın malzemesi parçacık boyutlarının belirlenmesi için görüntü işleme yöntemi kullanılarak boyut analizleri yapılmıştır. Daha sonra bu malzemenin içerisinde bulunan patarların hidrolik kırıcılar ile ikinci bir kırma işlemine tabi tutulması esnasında hidrolik kırıcıların net çalışma süreleri ve kırma hızları belirlenmiştir. Bu çalışma kapsamında ziyaret edilen kırmataş ocaklarında benzer özelliklere sahip hidrolik kırıcılar kullanılmaktadır. Bu doğrultuda, basit regresyon yöntemi kullanılarak kayaçların fiziksel ve mekanik özellikleri ile hidrolik kırıcı net üretim miktarları arasındaki doğrusal ilişkiler araştırılabilmiştir. Buna göre, iki değişken arasında farklı düzeylerde anlamlı doğrusal ve ters yönlü ilişkiler bulunmuştur. Ayrıca çalışmanın sonunda, bütün değişkenlerin dâhil edildiği çoklu regresyon analizi ile hidrolik kırıcının anlık üretim performansını önceden kestirecek bir model geliştirilmiştir.
Evaluation of rock slopes susceptible to circular failures using logistic and multiple regression models
(Springer, 2020) Sarı, Mehmet
The analysis of stability of slopes is a classical problem for geotechnical engineers. In practice, many methods are available for the desired purpose, from basic kinematic analysis to two- and three-dimensional limit equilibrium analyses and numerical modeling with various user-friendly softwares. However, additional techniques are also required to provide knowledge necessary for decision-making. In this research, a reliable dataset provided by Sah et al. (1994) was used to analyze the stability evaluation of rock slopes subjected to circular failures. For this purpose, using Slide 2018 program, 44 separate limit equilibrium slope models were built for each case given in the original work. The provided material properties and slope geometries in heavily fractured and/or very weak or highly weathered rock masses were considered during the model building stage. It was found that Slide 2018 program generated dissimilar safety factors compared to those given by Sah et al. (1994) for the investigated slope cases. Binary logistic and multiple linear regression techniques were implemented in the study to promote alternative approaches for the prediction of the stability condition and safety factor (SF) of slopes excavated in heavily fractured/highly weathered rock masses. The condition of slopes (stable or failed) was predicted by binary logistic regression model with 90.9% accuracy. The SF of the slopes was estimated by a multiple linear regression model with 95.6% accuracy. It was concluded that both statistical techniques could be sufficiently used as alternative approaches to predict the stability condition and SF of rock slopes prone to circular (rotational) failures.
Stability analysis of cut slopes using empirical, kinematical, numerical and limit equilibrium methods: case of old Jeddah–Mecca road (Saudi Arabia)
(Springer Verlag, 2019) Sarı, Mehmet
The stability of natural and man-made rock slopes has always been of great concern for engineering geology studies. To ensure a safe and functional design of excavated slopes, the first and most crucial step is to use reliable input parameters while searching for possible failure modes at the preliminary design stage. It is highly important for practicing engineers to determine the best material property for a chosen failure criterion. This study aims to analyze the stability condition of a case road cut from different aspects. For this purpose, two well-known failure criteria proposed for rock masses and rock joints were applied in the study depending on the scale of the problem in the slope face. The Hoek–Brown failure criterion was used to obtain input data required for modeling intact rock and rock mass behavior, and the Barton-Bandis shear strength criterion to determine the input data necessary for the modeling of rock joint behavior. SMRTool and Dips 7.0 programs were utilized to analyze the structurally controlled instabilities due to discontinuities in the cut slope. Slide 2018 and RS2 9.0 programs were executed to examine the stability condition of cut slope subjected to circular and non-circular failures, respectively. According to the results of numerical and limit equilibrium methods, no stability problem occurred in the case of slope due to non-sliding circular or non-circular slip failures. However, according to the results of empirical and kinematical analyses, some structurally controlled sliding failure modes of planar, wedge, and toppling were expected on the slope face. The result of this study clearly shows that to reach a final decision, different analysis methods should be used to evaluate the stability of cut slopes by considering various conditions of jointed rock masses.
Recycling of waste magnesite powders
(Foundation Environmental Protection & Research-Fepr, 2013) Erdoğan, Necmettin
Each year in Turkey, thousands of tons of magnesite ore is subjected to heat treatment. For this operation, billion of tons of magnesite ore is produced and beneficiation. Crushing process which is occur an important department of beneficiation plants, are produce as very thin waste powder magnesite which is average %25 of feed raw ore. So far, the amount of this type of material, approximately 500,000 tons of waste is known to be stocked. This material is 80% smaller than 165 microns, and average grain size d50 is 79 microns. This stock is very difficult to fine-sized material harm to the environment is inevitable. The purpose of this study, produced in large quantities so thin, the waste powder material, is investigate the possibilities of recovery, at the same time the material is to prevent harm to the environment. In this study, high purity Mg(OH)(2) production from fine waste magnesite powder was investigated. In experimental studies, the leaching method is used. The products obtained are repeated conditions. Chemical analysis is made to determine of the product compounds. According to the results of chemical analysis, the product compounds, Mg(OH)(2):99.35%, SiO2:0.15%, CaO:0.50% is seen from obtained. These results show that high-purity Mg(OH)(2) will be produced. In addition, the aimed to determine of the product characterization were made XRD analysis. According to XRD analysis results show that the product name is Brucite.
Development of an empirical model for predicting the effects of controllableblasting parameters on flyrock distance in surface mines
(Elsevier, 2012) Ghasemi, Ebrahim; Sarı, Mehmet; Ataei, Mohammad
Prediction of flyrock distance has a remarkable role in reduction and control of blasting accident in surface mines. In this paper, at first a new empirical equation for predicting flyrock distance was developed using dimensional analysis. The equation extended based on controllable blasting parameters that compiled from 150 blasting events in Sungun copper mine, Iran. Then, flyrock phenomenon is simulated using this equation and Monte Carlo (MC) method. Results showed that MC is a good means for modeling and assessing the variability of blasting parameters. Finally, sensitivity analysis was conducted to analyze the effects of the controllable blasting parameters on flyrock distance. Based on correlation sensitivity, the most effective parameters were powder factor, stemming and burden. Finally, it should be noted that the proposed flyrock equation and obtained results are site-specific; it should be used only in the Sungun copper mine, and it should not be used directly in other surface mines.
Effect of blasted rock particle size on excavation machine loading performance
(IMCET, 2007) Sarı, Mehmet; Lever, Paul J.A.
Earthmoving (i.e. excavation, loading and transportation of material) makes up a major portion of surface mining operations. Today, there is a wide array of equipment used to perform excavation and loading tasks in open pit mines. However, the performance of these machines is often not fully optimized since the excavated material characteristics have not been thoroughly investigated. In this study, results of some parts of a research project that is undertaken to quantify the factors effective on excavation machines' loading performance are presented. The research project originally consisted of performing mine site visits and collecting video camera images from typical front-end loader, cable shovel, and hydraulic shovel applications. In the study, the video images were carefully scanned to obtain machine loading cycle times and amount of hourly production whilst video images of the material being loaded were successively captured, scaled and processed to obtain rock fragmention size distributions of muckpile in the vicinity of blasted benches. Regression analysis on sitespecific data was statistically performed in order to investigate, if exists, possible linear relationships between machine performance parameters and particle size of blasted rock. The results suggested that there was little to be gained by attempting to match the performance of loading machines (loading cycle time and maximum production) with only size features (maximum and 63% passing) of excavated material.
Çoklu Duyusal Öğrenme’nin disleksi riski olan bir ilkokul 4. Sınıf öğrencisinin fonolojik farkındalık becerisine etkisi
(Mehmet Kurudayıoğlu, 2017) Balcı, Emine; Çayır, Aybala
Bu çalışmada; zihinsel, işitsel ve görsel bir engeli olmamasına rağmen okuyamayan bir ilkokul 4.sınıf öğrencisinin fonolojik farkındalığını arttırmak amaçlanmıştır. Bu amaç doğrultusunda ilgili literatür taranmış ve kavramsal bir çerçeve oluşturulmuştur. Bu öğrenciye; ilk aşamada harf, hece ve kelime okuma becerisi, ikinci aşamada ise akıcı okuma becerisi kazandırmak amaçlanmış, Çoklu Duyusal Öğrenme temelli bir okuma eğitimi programı hazırlanmıştır. Seçilen denek; çalışma öncesinde, harf, hece ve kelimeleri okuyamamaktadır. Öğrenciye okuma becerisi kazandırmak ve akıcı okumasını geliştirmek için; görsel, is?itsel, kinestetik/dokunsal stratejileri es?zamanlı olarak is?e koşan okuma çalışmalarından yararlanılmıştır. Çalışma hafta içi her gün yapılmış ve 32 saat sürmüştür. Çalışma sonunda öğrencinin; harf, hece ve kelime okuma becerilerinin gelişiminde önemli ölçüde başarı sağlandığı ve okuyabildiği gözlemlenmiştir. Öğrenci, kelime anlama düzey ve yüzdeliğini belirleme tablosundan %90’ın altında puan alarak akıcı okuma becerisinde endişe düzeyinde kalmıştır.
Atık manyezit tozlarının geri kazanımı
(Çevre Koruma ve Araştırma Vakfı, 2013) Erdoğan, Necmettin
Türkiye’de her yıl, binlerce ton manyezit cevheri ısıl işleme tabi tutulmaktadır. Bunun için de milyonlarca ton ham manyezit cevheri üretilmekte ve zenginleştirilmektedir. Zenginleştirme tesislerinin önemli bir bölümünü oluşturan kırma prosesi, tasarım ve dizayn sonucu olarak, giren ham cevherin ortalama %25’ini çok ince atık toz malzeme olarak üretmektedir. Bugüne kadar bu tip malzeme miktarı, yaklaşık 500.000 ton atık olarak stoklandığı bilinmektedir. Bu malzemenin %80’i, 165 mikrondan küçük olup ortalama tane boyutu olan d50, 79 mikrondur. Bu kadar ince boyutundaki malzemenin stoklanması oldukça zordur ve çevreye zarar vermesi kaçınılmazdır. Bu çalışmanın amacı, bu kadar çok miktarda üretilen, ince, atık toz malzemenin, geri kazanımı imkânlarını araştırmak, aynı zamanda da malzemenin çevreye zarar vermesine engel olmaktır. Bu çalışmada, ince atık manyezit tozundan yüksek saflıkta Mg(OH)2 üretimi araştırılmıştır. Deneysel çalışmalarda, liç metodu kullanılmıştır. Ürünler, tekrarlanır koşullarda elde edilmiştir. Çalışmalar sonunda elde edilen ürün bileşiklerinin belirlenmesi amacıyla kimyasal analiz yapılmıştır. Kimyasal analiz sonuçlarına göre, ürün bileşiklerinin; Mg(OH)2:%99,35, SiO2:%0,15, CaO:%0,50 den oluştuğu görülmüştür. Bu sonuç ile atık manyezit tozlarından yüksek saflıkta Mg(OH)2 üretilebileceği görülmüştür. Ayrıca, ürünün karakterizasyonunun belirlenmesi amacıyla XRD analizi yapılmış, XRD analizi sonuna göre de ürün adının Brusit olduğu belirlenmiştir.
Kızılkaya ignimbiritlerinde görülen süreksizliklerin incelenmesi ve kaya kütlesinin tanımlanması
(Selçuk Üniversitesi Mühendislik-Mimarlık Fakültesi, 2007) Sarı, Mehmet; Çömlekçiler, Fuat
Ülkemizin önemli doğal ve tarihi anıtlarından biri olan Ihlara Vadisi, İç Anadolu Bölgesi'nin Aksaray İli sınırları içerisinde yaklaşık 52 km2/lik bir alanı kaplar. Jeomorfolojik yapı, volkanizma, hidrotermal etkinlik, tarihi ve kültürel çeşitlilik bakımından dünyada çok ender görülen bir özelliğe sahiptir. Bu bölgede, Melendiz çayı drenaj sisteminin sert ignimbirit kalkanını ve bunun altında yer alan yumuşak tüfleri kesmesi ve atmosferik şartlara bağlı olarak gelişen aşınma sonucunda kanyonumsu akarsu vadileri meydana gelmiştir. Kızılkaya ignimbiritleri, Kızılkaya köyünün kuzeyinde daha güzel görünümlü olup, ilk defa Beekman (1966) tarafından bu isimle adlandırılmıştır. Genelde beyazımsı gri renkli olup bozunmuş yüzeyleri pembe görünümlüdür. Masa tepecikler şeklinde ve sütunsu görünüm sunan Kızılkaya ignimbiritlerinde, belirgin bir şekilde gelişmiş olan soğuma çatlakları ile diğer sistemlerde gelişmiş olan kırık ve çatlakların atmosferik etkenlerle daha da gelişmesi sonucunda bloklar halinde kopmalar meydana gelmektedir. Kaya kütlesinin tanımlanması; jeolojik, fiziksel ve mekanik özelliklerinin tanımlanmasıyla ilgili verilere ait bir modelin oluşturulmasıdır. Bu işlemde en önemli aşama, süreksizliklere ait özelliklerin belirlenmesidir. Bu çalışmada, Kızılkaya ignimbiritlerinde yapılan 75 adet süreksizlik ölçümünden faydalanarak, kayacın mühendislik özellikleri tespit edilmiştir. Bu özellikler, süreksizliklerin (çatlak, fisür, kırık vs.) eğimi ve yönelimi, süreksizlik aralığı ve açıklığı,süreksizlik devamlılığı ile yüzey pürüzlülüğü ve dalgalılığı dikkate alınarak değerlendirilmiştir. Ortalama değerlere göre, süreksizliklerin doğrultu yönleri KD-GB, eğim değerleri 87.5° GD, süreksizlik açıklığı 4.5 cm., süreksizlik devamlılığı 23.6 m. ve süreksizlik aralığı 3.44 metredir. İnceleme alanında yapılan Schmidt çekici sertlik tayininde Kızılkaya ignimbiritlerinde sağlam kayaç için 46.8, bozunmuş kayaçta ise 39.3 değerlerine ulaşılmış ve bu değerlere göre ignimbiritlerin az bozunmuş kayaç sınıfına girdikleri belirlenmiştir. İgnimbiritlerde süreksizlik yüzeyi dayanımı (JCS) 50.3 MPa olarak hesaplanmıştır. Kaya Kütlesi Sınıflaması (RMR) (Bieniawski, 1989) sistemine göre yapılan sınıflamada ignimbirit kaya kütlesi iyi kayaçtır.
Çok kriterli karar verme yöntemleri ve madencilik sektöründe kullanımı
(TMMOB maden mühendisleri odası, 2017) Sarı, Mehmet; Mutlu, Mert
Çok kriterli karar verilmesi (ÇKKV) hem objektif hem de sübjektif değerlendirme içermektedir. Yapılan bu derleme çalışmasında, literatürde çok kriterli karar verme yöntemlerinin kullanıldığı madenciliğin farklı alanlarında yapılmış çalışmalar incelenmiştir. Söz konusu yöntemlerin risk yönetim planlaması sürecinde kullanımından, uygun ekipman seçimi problemlerine, üretim yöntemi seçiminden, tesisler için uygun yer belirlenmesine, doğal taş ocaklarında kesme yöntemi seçimi gibi birçok farklı alanda kullanıldığı görülmüştür. Çok kriterli karar verme yöntemleri yardımıyla karar verme sürecinde seçimi yapılmak istenilen alternatifler uygun bir ölçek kullanılarak sıralanabilmekte, böylece madencilikte karşılaşılan çeşitli problemlerin çözümünde karar vericilere yol gösterici nitelikte uygun seçenekler sunabilen faydalı birer araç olabilmektedirler.
Predicting mechanical strength loss of natural stones after freeze-thaw in cold regions
(Elsevier, 2012) Bayram, Fatih
Natural stones are generally used as building materials for construction and decoration. Determining the deteriorations of stones after freeze-thaw cycles is important subject for natural building stones used in cold regions exposed excessive freezing and thawing during the year. Freeze-thaw test is conducted for determining the deteriorations of stones due to freeze-thaw cycling. The percentage loss in uniaxial compression strength is an important parameter indicating these deteriorations. However, it is extremely laborious and time consuming tests. Because of this, predicting the percentage loss values in uniaxial compression strengths from intact rock properties was the purpose of this paper. Freeze-thaw tests were applied on nine limestone samples selected from different cold regions of Turkey. All of them except two samples were found to be suitable for use in cold regions. A statistical model was developed for predicting the percentage loss values in uniaxial compression strength from intact tests of impact strength, modulus of elasticity and water absorption. This model equation is very reliable (R-2=0.95) and can be very useful for predetermination of uniaxial compression strengths of limestones after freeze-thaw test without testing. (C) 2012 Elsevier B.V. All rights reserved.
An improved method of fitting experimental data to the Hoek-Brown failure criterion
(Elsevier, 2012) Sarı, Mehmet
In this study, a special fitting technique is proposed to apply the Hoek-Brown failure criterion to available laboratory strength data collected on samples of Ankara andesites. The original method of fitting the Hoek-Brown failure criterion using the spreadsheet and the fitting method utilized in the RocLab software are statistically compared with this new modified nonlinear fitting technique. The Hoek-Brown failure parameters obtained by a simple multiple regression technique, utilizing the solver function within an Excel spreadsheet and the revised least squares procedure significantly improved the fitness of the Hoek-Brown envelope especially within the tensile and high confining stresses. The Brazilian tensile strength is found to be a useful parameter to fix a rock failure criterion at low confining stresses, particularly, in the tensile region. If tensile, uniaxial and triaxial test results are available, when compared to two existing fitting methods the modified multiple regression method is found to predict more precise tensile and compressive strengths, and material constant m(i) for the Hoek-Brown failure criterion. (C) 2011 Elsevier B.V. All rights reserved.

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