LEE- Maden Mühendisliği Lisansüstü Programı

Bu topluluk için Kalıcı Uri

http://hdl.handle.net/11527/19364

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Yazar "Çopur, Hanifi" ile LEE- Maden Mühendisliği Lisansüstü Programı'a göz atma
  • Öge
    EPB TBM'lerde kullanılan köpüklerin özelliklerinin killi bir zeminin şartlandırılmasına etkileri
    (Lisansüstü Eğitim Enstitüsü, 2024-07-10) Çınar, Osman Faruk ; Çopur, Hanifi ; 505211008 ; Maden Mühendisliği
    Tez çalışmasının temel amacı köpük karakteristikleri (köpük kimyasalı yoğunluğu, köpük yarı-ömrü, köpük plastikleşme etkisi) ile şartlandırma karakteristiği (optimum FIR, penetrasyon, güç tüketimi, yapışma, kesme dayanımı) arasındaki ilişkileri-trendleri incelemektir. Ayrıca, şartlandırma deney sonuçları arasındaki ilişkiler-trendler de incelenmiştir. Deneylerde üç baz köpük, iki aşınma önleyici ve bir anti-kil (yapışma önleyici) köpük kimyasalı kullanılmıştır. Deneylerde kullanılan köpük kimyasallarının özellikleri köpük kimyasalı yoğunluğu, köpük yarı-ömrü deneyleri ve köpüğün plastikleşme etkisi (standart kum-köpük karışımında yayılma tablası) deneyi ile ölçülmüştür. Zemin numunesinin karakteristiklerini belirlemek amacıyla doğal nem içeriği, Atterberg kıvam limitleri (likit ve plastik limitler) ve boyut dağılım deneyleri (elek analizi ve hidrometre) yapılmıştır. Zemin+köpük karışımının karaktersitiklerini belirlemek için güç ve yapışma ölçümlü mikser deneyi, konik penetrometre deneyi ve cep tipi kanatlı kesme (vane shear) deneyi yapılmıştır. Zemin+köpük karışımının karaktersitiklerini ve köpüğün plastikleşme etkisini belirlemek için kullanılan köpükler sabit köpük konsantrasyonunda (Cf = %3), sabit köpük genleşme oranında (FER = 15) ve sabit su içeriğinde (Wn = % 67) üretilerek, köpük enjeksiyon oranı %0 ile %40 arasında değiştirilmiştir. Bu çalışma sonucunda köpük yarı-ömrü arttıkça, yapışma ve kesme dayanımının arttığı görülmüştür. Bu durum kil numunelerde daha düşük yarı-ömürlü (dolayısı ile genellikle daha ucuz) köpük kimyasallarının tercih edilmesi gerektiğini göstermektedir. Ancak, yarı-ömrün çok düşük olması da köpüğün işlevini tam olarak yerine getirememesi riski oluşturabilecektir. Şartlandırma deneylerinin kendi aralarındaki ilişkilere bakıldığında ise yapışma ölçümlü karıştırma deney sonuçları kullanılarak zemin + köpük karışımının kesme dayanımının tahmin edilebileceği görülmüştür.
  • Öge
    Investigation of vibrations created during TBM excavation and rock cutting
    (Graduate School, 2024-06-11) Ateş, Uğur ; Çopur, Hanifi ; 505132005 ; Mining Engineering
    Tunnel Boring Machines (TBMs) are widely employed in infrastructure projects due to their high advance rates and providing a safe working environment. The TBMs should be operated in accordance with the geological conditions to achieve optimal excavation rates. The majority of contractors, especially the ones working in remote locations, predominantly depend on the geological information provided during the tender phase or undertake a limited number of supplementary geotechnical investigations prior to starting projects. Especially in remote locations that characterized by a limited geological data, the expertise of the crew becomes highly significant. Although the most effective way of assessing geological conditions during tunnel excavation involves examining the excavation face, contractors often hesitate to halt excavation for face inspections unless deemed necessary or forced by contractual obligations. Furthermore, the application of closed-face soft ground TBMs often renders face inspections impractical. Although alternative techniques such as probe drilling or geophysical methods could be applied in the TBMs, these approaches require considerable amount of time, with some geophysical methods still undergoing development. Given the reluctance of contractors to allocate resources towards new geological studies and the necessity for continuous geological information it becomes evident that a system capable of providing real-time information to the TBM crew regarding the encountered geological conditions is required. Since the TBMs vibrate during excavation, utilizing vibrations to understand the geological conditions ahead seems practical. In this context, field measurements of the vibrations generated during excavation by TBMs have been investigated for ground identification in various studies. However, TBMs include too many influential factors and noise sources that impact the vibrations (e.g., multiple cutters on the cutterhead, motors and other parts in shield and backup area, etc.), requiring a deeper understanding of vibrations specifically arising from the rock cutting process within a more controlled environment. Even some authors focused laboratory analyses and investigated the vibrations generated during rock cutting tests, these experiments remain fairly limited. The principal objective of this study is to understand the vibrations generated during the TBM excavation and provide a system that could give information to the site crew regarding the geological conditions on the excavation face. To reach this goal, a special vibration data recording system has been developed and installed onto four Earth Pressure Balance Tunnel Boring Machines (EPB TBMs), excavating in three different project sites; that are Mecidiyeköy-Mahmutbey Metro Line, Umraniye-Atasehir-Goztepe Metro Line and European Region Potable Water Transmission Tunnel. The employed vibration recording system comprises accelerometers, analog-digital converters, and a dedicated computer running custom-designed data recording software tailored for the purpose of this project. Initial deployment and testing of the system took place at the Mecidiyekoy-Mahmutbey Metro Line project site. Following this initial implementation, the system underwent further refinement, with the addition of new features and hardware enhancements. A total of 6 km tunnel excavation was monitored, and vibration data continuously recorded in three orthogonal directions (x, y, and z). The influence of geological conditions including soils and hard rocks, EPB TBM operating parameters (thrust, torque, face pressure, cutterhead rotational speed, penetration rate), cutter damages/breakages, positions and types of accelerometers, and TBM diameters on vibration were investigated. During vibration analysis, primarily Root Mean Square (RMS) and interval RMS vibrations, together with different vibration statistics were used. A comprehensive analysis was conducted on the collected TBM vibration data, incorporating geological information, site shift reports, and disc changing logs. This analysis revealed a significant influence of geological and lithological variations on the vibration patterns generated during excavation. In particular, moderately strong to strong correlations were observed between interval RMS acceleration values and rock mass parameters such as Rock Quality Designation (RQD) and Geological Strength Index (GSI). The analysis yielded a clear trend, an increase in rock strength corresponds to rise in TBM vibrations, while vibrations greatly reduced in the case of weathered rocks and soils. The presence of short weathered zones was distinguishable in the vibration data. This characteristic suggests that the measurement has the potential to serve as an early warning system for detecting geological transitions during TBM excavation. Furthermore, an acceleration threshold value of 1g, representing the percentage of data points surpassing this limit, is established as an effective marker for distinguishing between different lithological units. It is observed that the vibrations recorded in TBMs could exceed 10g. The analysis also revealed an influence by the operational parameters of TBMs and conditions of the cutters on the vibrations. Notably, it was observed that broken disc cutters produce distinct high-amplitude vibrations. Considering the noise sources in TBMs, it is acknowledged that there is a need for a better understanding of vibrations created during the rock cutting process under more controlled environment. With this objective, laboratory rock cutting tests were conducted using a Full-Scale Linear Rock Cutting Machine (FLCM) equipped a 17-inch constant cross section (CCS) disc cutter. To record vibrations, FLCM was equipped with five accelerometers. Three different rock samples were used (siltstone, mudstone and beige marble) having uniaxial compressive strength values ranging from 21 to 82 MPa. During the experiments, it was discovered that the beige marble sample exhibited two distinct mineralogical characteristics on its left and right sides.
  • Öge
    Performance prediction and optimization of raise boring machines (RBMs)
    (Graduate School, 2022-09-09) Mamaghani Shaterpour, Aydın ; Çopur, Hanifi ; 505142010 ; Mining Engineering
    Raise Boring Machines (RBMs) continue to find extensive application in the mining and tunnelling industries because of the many advantages compared with drill and blast methods. These machines as the fast, safe, and efficient excavation machines are used for different purposes such as excavation of ventilation and ore transport shafts in the mines, switching lines between underground subway tunnels (horizontal), and ventilation shafts in the road and railway tunnels. In the conventional raise boring method, the machine is set up on the upper level of the two levels to be connected. Then, a small diameter hole (pilot hole) is drilled by a sealed bearing tricone bit to the lower level. Once the rod (drill string) breaks into the opening on the target level, the pilot bit is removed and a reamerhead with roller button cutters is connected to the rods and raised back up towards the upper level. The debris and cuttings from the reamerhead during drilling fall on to the lower level and from there a conventional method is used to take them out. Although a high price in foreign currency is paid for purchasing these machines, sometimes the performance (productivity) of the machines would be too low, rod jamming, and shaft deviation problems might be encountered. Consequently, the selection and design of these machines according to the project and excavation environment, predicting accurately their performance, and maximization (optimization) of the performance become very important in terms of the economics of the project in the feasibility and planning stages. Predicting the performance of an RBM is one of the important subjects in mechanized shaft / raise excavation to estimate costs and job completion time that directly affects the project economics. The parameters affecting the selection, design, and prediction of the performance of an RBM can be classified into three general categories: mechanical (machine-related) parameters, geological / geotechnical parameters, and operational parameters. A suitable RBM should be selected / designed for the geological / geotechnical conditions to be encountered during the shaft excavation. Utilizing the highest rotational speed and correct bit load for specific rock formation could lead to an optimum rate of penetration and bit service life. Cutters with larger row spacing are suitable for reaming in softer rocks. However, cutters with narrow spacing are suitable for reaming in very hard and tough rocks where the thrust forces cannot be fully utilized. Identification of fault zones and broken ground along the shaft alignment are the key requirements for successful shaft excavation with RBMs. A comprehensive rock-testing program is the most important requirement for the assessment of RBMs, and by use of the obtained data from the rock-testing program the best-suited raise bore machine for each project could be selected. Samples of all different rock types in the excavation area should be included in the laboratory studies. Moreover, site preparation plays an important role in the elimination of delay and increasing the efficiency of the raise boring operation. Load per cutter, reamerhead diameter, geological formation, and inclination of the shaft are some important factors affecting the torque requirements. Increasing shaft diameter causes additional torque effort on the drill string and reamer stem. In addition, with the increase in diameter, there is a greater potential for instability of the shaft walls and the advancing face of the shaft. The basic aim of this thesis research is to propose new empirical and deterministic models for proper selection, design, and prediction of operational and performance parameters including daily advance rate, rotational speed, weight on bit (pushing force of tricone bit), net reaming thrust (pulling) force, tricone bit / reamerhead torque and power, unit penetration rate, instantaneous penetration rate, field specific energy, and machine utilization rate of RBMs. In order to reach the goals of this thesis, firstly, the related mine and tunnel sites are visited for obtaining information on the geology of the field, the applied excavation method, and the specifications of the RBMs; collecting rock samples from the formation(s) excavated; and collecting field operational-performance data. The obtained rock core samples are used for the determination of the physical-mechanical properties and indentation tests, and block samples are used for the full-scale linear cutting tests. The experimental studies start by determining some important physical-mechanical properties of intact rock samples including uniaxial compressive strength, indirect (Brazilian) tensile strength, static and dynamic elasticity modulus and Poisson's ratio, acoustic wave velocities (P and S wave velocities), Schmidt hammer, Shore scleroscope, Cerchar abrasivity, and petrographic analysis. Rock Quality Designation (RQD) values are also determined based on geotechnical reports of the related sites. Then, indentation tests (by an insert tip with a diameter of 22.2 mm and width of 11 mm) are performed on the core samples from the fields and rectangular rock pieces obtained from the remnants of the block samples. Finally, a series of full-scale linear cutting tests in five different rock types (diabase, granodiorite, skarn, limestone-1, and limestone-2) with a 305 mm (12 inches) diameter button (kerf) cutter having an insert tip width of 11 mm are performed to generate a new RBM performance database. This research demonstrates the challenges of collecting long-term operational data in raise boring operations. Although this thesis includes raise boring operation data collected over six years, it has some limitations such as the number of data, rock mass parameters, different reamerhead diameters, and different raise inclinations. The models presented in this study are limited by the data content, the upper and lower limits of the data, and the assumptions made on a few issues mentioned in this thesis. The results of the experimental studies indicate that the mechanical properties of the rock samples vary in a wide range and the collected rock samples are in all types of geological origins (sedimentary, igneous, and metamorphic). In the inclined raise-bored shafts static elasticity modulus and Brazilian tensile strength could be good predictors for the field specific energy of reaming operations. In addition, the operational parameters of pilot hole drilling and the physical-mechanical properties of rocks may be used to predict the performance parameters of reaming in both vertical (90°) and inclined (70°) raise-bored shafts. Moreover, direct and indirect deterministic approaches are able reliably to predict the unit penetration and instantaneous penetration rates of RBMs. Besides, indentation tests indicate that the brittleness index of rocks may be predicted by using the velocity of the S-wave and the Cerchar abrasivity index parameters. Finally, this study shows the feasibility of using the power function on the relationships between the indentation force and the penetration values for predicting the performance of RBMs. The outcome of this study establishes a new database to assist on predicting the performance parameters of RBMs. The proposed empirical and deterministic models in this study can be used by the designer engineering companies, contractor companies, and project owner institutions in the feasibility and planning stages of the projects.
  • Öge
    Türkiye maden ihracatı ekonomisi ve pazar yapısı: MINT ülkeleri ile karşılaştırılması
    (Lisansüstü Eğitim Enstitüsü, 2021) Başyiğit, Mikail ; Çopur, Hanifi ; 708279 ; Maden Mühendisliği
    Türkiye zengin ve kompleks bir jeolojik geçmişe sahip olsa da bu zenginliğini maden ihracatına yansıtamamıştır. Kalkınma raporları ile ortaya koyulan maden ihracatı hedefleri tutturulamamıştır. Bu durumun çeşitli nedenlerden kaynaklansa da pazar yapılarının dikkate alınmaması, pazar yoğunlaşması, pazar bağımlılığı gibi sebepler de ihracat hacminin üzerinde etkilidir. Buradan hareketle maden ihracatı miktarının artırılması ve dalgalanma risklerine karşı daha dirençli hale getirilmesi için pazar yapılarının ve ihracatını etkileyen faktörlerin belirlenmesi önemlidir. Ayrıca pazar yapılarının yakın ekonomik büyüklükteki ülkeler ile karşılaştırılması içinde bulunulan durum hakkında bilgi sağlayacaktır. Gerçekleştirilen çalışma kapsamında, 2002-2020 yılları arasında Türkiye maden ihracatı önce toplam olarak sonra da ürün bazlı olarak ele alınmıştır. Toplam ihracat baz alınarak gerçekleştirilen pazar analizleri Türkiye maden ihracatının ve pazar yoğunlaşmasının 2013 yılına kadar arttığını, 2013 yılından sonra da azaldığını göstermektedir. Bu azalmanın, Çin'in Türkiye'den ithalat miktarının ve payının kaynaklandığı tespit edilmiştir. Bunun neticesinde Çin'in Türkiye'den maden ithalatında etkili parametreler araştırılmış ve baskın faktörlerin Çin'in kişi başı geliri ve Yuan'ın Lira karşındaki alım gücü olduğu belirlenmiştir. Çin'in ve pazar yoğunlaşmasının hangi mineral ürünleri üzerinde etkili olduğunun tespiti için ürün bazlı pazar yoğunlaşması analizleri gerçekleştirilmiştir. Analizler, Çin'in ana ithalatçı olduğu tüm pazarlarda Çin'in büyümesine bağlı olarak daralma olduğunu ortaya koymuştur. Türkiye'nin ikinci büyük maden ihracatı partneri ABD'nin ithal ettiği ürün portföyü incelenmiş ve temel ithalat kaleminin işlenmiş mermer olduğu tespit edilmiştir. Bu nedenle işlenmiş mermer talebine etki eden faktörlerin belirlenmesi hedeflenmiştir. İşlenmiş mermer son tüketicinin ulaşabileceği bir maden ürünü olduğundan moda ve kişisel tercihlerin mermer talebi üzerinde etkili olduğu düşünülmüştür. Google Trends ile elde edilen trend verileri genel talep modelline eklenmiş ve modeli iyileştirmiştir. Benzer ülkelerin maden ihracatı pazarları incelenerek Türkiye'nin mineral ihracatındaki yeri ve pazar performansı bu ülkeler ile karşılaştırılmıştır. Bu ülkeler içinde en küçük pazar hacmine ve pazar yoğunlaşmasına sahip ülke Türkiye olmuştur. Son olarak maden ihracatı ile ekonomik büyüme arasındaki ilişki incelenmiş ve maden ihracatı ile ekonomik büyümenin eş bütünleşik olduğu yani birbirlerine etki ettikleri ortaya konmuştur