Kabataş – Mecidiyeköy Metro Hattı'nda NATM-TBM yöntemlerinin çok yönlü incelenmesi ve maliyet mukayesesi
Examination and cost comparison of NATM-TBM methods in Kabatas - Mecidiyekoy metro line
Yazar: MUSTAFA BUĞRA EMEKLİ
Danışman: PROF. DR. ZÜBEYDE ÖZTÜRK
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Ulaştırma Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2021
Konu: Ulaşım = Transportation ; İnşaat Mühendisliği = Civil Engineering

Özet:
Yapılan çalışmada Yeni Avusturya Tünel Açma Metodu (NATM) ve Tünel Delme Makinası (TBM) yöntemleri ele alınarak; Kabataş – Mecidiyeköy Hattı'nda kullanılan iki metodun maliyet karşılaştırması yapılmıştır. Metro inşaatlarının şehir merkezlerinde ya da nüfus yoğunluğunun fazla olduğu bölgelerde yapıldığı göz önünde bulundurulduğunda, yapılan imalatların zaman ve maliyet olarak ne denli önemli olduğu ortaya çıkmaktadır. Bu sebeple kullanılan her iki yöntemin de birbirlerine olan avantajları olsa da beklendiği üzere maliyet ve zaman olarak bir yöntemin diğer yönteme göre önde olması kaçınılmaz bir sonuç olarak karşımıza çıkmaktadır.
Tezde öncelikle ele alınan metro hattı olan Kabataş-Mecidiyeköy Hattı ile ilgili tanıtım bilgileri verilmiştir. Ardından kullanılan tünel açma yöntemlerinden ilki olan NATM yönteminin uygulanma aşamaları ve imalat adımları olan kazı, çelik hasır, çelik iksa, püskürtme beton, kaya bulonu, süren ve umbrella boruları, zemin çivisi ve tünel kaplama imalatları hakkında özet bilgiler verilmiştir. Ardından TBM makinelerinin türleri anlatılarak, Kabataş-Mecidiyeköy Hattı'nda kullanılan ve TBM türlerinden biri olan Arazi Basınç Dengeleme (EPB) makinası hakkında bilgilendirme yapılmıştır.
İnceleme bölgesi olarak; fiili durumda NATM yöntemi kullanılarak açılan ana hat tünellerinin TBM makinası kullanımına da elverişli olması sebebiyle L05 Fulya-Mecidiyeköy Bölgesi seçilmiştir. İlgili bölgede toplamda 1.296,76 metre A tipi tünel bulunmakta olup, fiili olarak zemin koşullarının değişkenliği sebebiyle kullanılan iki farklı kazı ve destekleme sistemi hakkında bilgiler verilmiştir. 
Çalışma sonucunda, Kabataş-Mecidiyeköy Hattı'nın geçmiş dönemde hattın başka kısımlarında yapılan TBM imalatları baz alınarak ortalama günlük TBM ilerleme miktarı hesaplanmış ve fiili olarak NATM yöntemi ile imalatı tamamlanan ana hat A tipi tüneller maliyet ve zaman anlamında mukayese edilmiştir.
Yapılan mukayese neticesinde, ihale edilen projelerde yapım aşamasına geçilmeden önce yapım yönteminin net bir şekilde belirlenmemiş olması, hem idarenin hem de yüklenici firmaların karşısına finansal bir yük olarak çıkmaktadır. İstanbul'da halihazırda yapımı tamamlanan, inşa aşamasında ya da yapımı planlanan projeler de göz önünde bulundurulursa, tezde ele alınan Kabataş – Mecidiyeköy Hattı'nda olduğu gibi bu projelerde de kamusal yatırımın boşa harcanması söz konusu olabilecektir.

Abstract:
Day by day, there is a population growth in urbanization areas in the world. In order for each individual to maintain his daily life, transportation from one place to another has been in question, and for this reason, problems in transportation have started to occur with the increase in population.
Since highways have been the most used type of transportation at the past, investments were made in highways whenever needed, and solutions were sought by increasing the total length of roads in cities. However, with each new road built, the number of vehicles increased, and there was no reduction in traffic density and harmful exhaust fumes.
For all these reasons, steps have been taken to rehabilitate this problem by introducing another mode of transportation by the state governments of the countries. Railways commonly used for freight transport; gained value as a result of these problems experienced in highways. In addition, it will become a type of transportation that will add great value and development, starting with the 19th century. This development, which has continued until today, has been crowned with the advancement of technology and has begun to play an active role in both urban and intercity transportation.
If we leave the intercity passenger and freight transportation aside, metro projects have a great importance in urban public transportation. Metro projects, due to the purpose of being built in city centers, are rail systems that have great difficulties especially for the construction phase compared to the known suburban or light rail systems. Due to the surface structuring in city centers, subways are implemented with underground structures. While tunnels, which were underground structures in the past, were only used to overcome difficult mountain obstacles; but today, it is also used in metro projects in city centers.
The transition of urban public transport from road-based systems to rail systems started with the first subway project in London, which was completed in 1863. Since then, many techniques have been developed in tunneling methods. With each technique applied, a lot of experience has been gained and the techniques used today have been created. There are two types of tunneling methods that are generally used all over the world. These are: New Austrian Tunneling Method (NATM) and Tunnel Boring Machine (TBM).
New Austrian Tunneling techniques are used in called conventional method. Each production to be made is carried out by different machines and workers. Excavator and loader for excavation, robot and mixer for shotcrete, platform for reinforcement works, jumbo and rock drilling machines are used for drilling works. Similarly, in tunnel lining manufacturing: platform for reinforcement works, rail steel formwork and scaffolding system for formwork, pump and mixer for concrete are used. 
In the Tunnel Boring Machine, all operations are carried out by a single machine. After the TBM machine completes the excavation production, it completes the coating production with precast concrete segments. TBM Machine has a cross-sectional area equal to the tunnel cross-sectional area to be excavated. There is a cutter head at the head, a rotating crane behind it and conveyor bands used for transporting the excavation material.
There are many types of TBM machines. In order to adapt to variable ground conditions, it is divided into two as hard rock and soft rock machines. The machine used in hard rocks takes the pushing power from the hard rock by using the soil formation and thus progress is made. On soft soils, Earth Pressure Balance (EPB) Machines and Slurry Machines are used. In EPB and Slurry Machines, the excavation material that comes out during excavation is accumulated in the cutter head and pressure is applied to the excavated surface.
According to the New Austrian Tunneling Method, the initial cost of the Tunnel Boring Machine Method is high and the construction cost is low. For this reason, NATM method is used in short lines and TBM is used in long main line tunnels. Although both methods have some advantages over each other, it is difficult to make cost comparisons. Choosing the tunnel construction method; depends on many variables such as time, soil type, project length, financial strength, machinery.
This study has been carried out because the cost comparison of NATM and TBM methods will be realized thanks to the experience and scientific studies to be gained after each completed project.
In the study, the New Austrian Tunnelling Method (NATM) and Tunnel Boring Machine (TBM) methods were taken into consideration; The cost comparison of the two methods used in the Kabataş - Mecidiyeköy Metro Line was made. Considering that metro constructions are made in city centers or in areas with high population density, it becomes clear how important the productions are in terms of time and cost. For this reason, although both methods used have advantages over each other, as expected, it is an inevitable result that one method is ahead of the other in terms of cost and time. 
In the thesis, firstly, introductory information about the Kabataş-Mecidiyeköy Metro Line, which is the subway line discussed, was given. Then, brief information was given about the application stages of NATM method, which is the first of the tunneling methods used, and the manufacturing steps of excavation, steel mesh, steel shoring, shotcrete, rock bolt, driving and umbrella pipes, soil nails and tunnel lining manufacturing. Then, by explaining the types of TBM machines, information was given about the EPB machine, which is one of the TBM types used in the Kabataş-Mecidiyeköy Metro Line. 
As the study area; L05 Fulya-Mecidiyeköy Region has been selected since the mainline tunnels opened using the NATM method are also suitable for the use of TBM machines. There is a total of 1,296.76 meters of A-type tunnel in the relevant area, and information was given about two different excavation and supporting systems that are actually used due to the variability of ground conditions. 
As a result of the study, the average daily TBM progress of the Kabataş-Mecidiyeköy Line was calculated based on the TBM productions made in other parts of the line in the past period, and the main line A type tunnels, which were actually manufactured by NATM method, were compared in terms of cost and time.
As a result of the cost comparison, the fact that the construction method has not been clearly determined before the construction phase in the tendered projects is a financial burden for both the administration and the contractor companies. Considering the projects that are already completed, under construction or planned to be built in Istanbul, it may be possible to waste public investment in these projects, as in the Kabataş - Mecidiyeköy Line discussed in the thesis.