Ayazağa su tünelinde yapılan konsolidasyon enjeksiyonu ile kaya kütlesi özellikleri arasındaki ilişkinin jeoistatistiksel analizi
Geostatistical evaluation of relation with rock mass properties and consolidation grout carried out in Ayazaga water conduit tunnel
Yazar: ÖMER FARUK KAP
Danışman: DOÇ. DR. HAKAN TUNÇDEMİR
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Maden Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2014
Konu: Jeoloji Mühendisliği = Geological Engineering ; Maden Mühendisliği ve Madencilik = Mining Engineering and Mining ; Mühendislik Bilimleri = Engineering Sciences
Dizin: Büyük Melen Nehri = Great melen River ; Jeoistatistik = Geostatistics ; Jeomekanik = Geomechanics ; Jeomekanik sınıflandırma = Geomechanical classification ; Jeomekanik özellikler = Geomechanical properties ; Mühendislik jeolojisi = Engineering geology ; Veri madenciliği = Data mining ; Yer altı madenciliği = Underground mining ; Zemin enjeksiyonu = Soil grouting ; Çimento enjeksiyon yöntemi = Cement grouting method

Özet:
Bu çalışmada, tünel tahkimatı ile kaya kütlesi arasında kalan boşlukların doldurulması amacıyla yapılan konsolidasyon (pekiştirme) enjeksiyonu uygulaması jeoistatistiksel açıdan irdelenerek analiz edilmiştir. Enjeksiyon verileri ile zayıf kaya kütlesi arasındaki ilişki incelenerek ortaya çıkan sonuçlar detaylı olarak raporlanmış ve yorumlanmıştır.  
Çalışma sahası olarak, 'Melen Suyu Projesi' kapsamında 'SP-6  Cumhuriyet Terfi Deposu-Kağıthane Arası İsale Hattı' etabında bulunan Ayazağa Tüneli incelenmiştir. Bu tünel delme-patlatma yöntemi kullanılarak açılmıştır. Her adımda kazı aynasından faydalanarak Q kaya sınıflama değerleri kaydedilmiştir. Önceden belirlenmiş tahkimat tipi tablosuna bakılarak Q değerine göre tahkimatın yapılmasının ardından su taşıyacak olan çelik borular yerlerine yerleştirilmiştir. Çelik boru ile tünel arasında kalan kısım dolgu betonu ile doldurulmuştur. Ortamın stabilitesini sağlamak için ise tahkimat ile kayaç arasındaki boşluklar ve çatlaklar konsolidasyon enjeksiyonu yapılarak doldurulmuştur. Kazı esnasında elde edilen jeolojik parametreler ile enjeksiyon sırasında elde edilen enjeksiyon verilerinden faydalanılarak kaya kütlesi kalitesi ile basılan enjeksiyon miktarı arasındaki ilişki jeoistatistik methoduyla detaylı bir şekilde incelenmiştir. 
Çalışmaya ilk olarak, literatür araştırmaları ile önceki çalışmalar incelenerek başlanmıştır. Bu kapsamda Q kaya kütle sınıflandırması, enjeksiyon uygulamaları, çalışma sahasının jeolojisi ve jeoistatistik konuları detaylı olarak incelenmiştir. Ayazağa Tüneli'nde çalışmaları gerçekleştiren firmanın proje yetkilileriyle görüşülerek çalışmalar yerinde gözlemlenmiş, gerekli bilgiler edinilmiş ve mevcut veriler alınmıştır. 
Ayazağa Tüneli, projenin 20+586,96 ile 18+009,91 km'leri arasında bulunmaktadır. Fakat elde edilen veriler 20+583 - 20+229 ve 19+389 - 18+256  km'leri arasını kapsamaktadır. Veri olarak, bu km'ler arasında bulunan ayna profili haritaları ve enjeksiyon raporlarındakilerden faydalanılmıştır. Jeoistatistiksel yöntem kullanılarak mevcut veriler yüksek doğruluk oranı ile istenilen miktarda çoğaltılmıştır. Bu sayede inceleme daha detaylı ve sağlıklı bir şekilde gerçekleştirilebilmiştir.
Elde edilen bulgular incelendiğinde, çelik boruların tepesindeki deliklerde basılan enjeksiyon miktarları en yüksek, orta kısımdaki deliklerde orta, taban kısımdaki deliklerde ise en düşük olduğu görülmüştür. Bunun sebebi de, tünel kazısı sonrasında tünelin üstünde kalan kısmın tünele doğru akma isteğiyle gevşemesi daha boşluklu bir yapı meydana getirmesindendir.
Ayrıca, konsolidasyon enjeksiyonunun kaya kütlesi özelliklerine göre değişimini tespit edebilmek amacıyla kaya kütle sınıflaması değeri olan Q Tünelcilik indeksi ve kaya kalitesi değeri olan RQD parametreleri ile enjeksiyon miktarı arasındaki ilişki irdelendiğinde kaya kütlesinin kalitesi arttıkça bünyesine giren enjeksiyon miktarının azaldığı görülmüştür.
Sonuç olarak, konsolidasyon enjeksiyonunun kaya kütlesi özelliklerine göre değişiminin tespiti için kaya kütle sınıflama değeri olan Q ve kaya kalitesi değeri olan RQD parametreleri ile enjeksiyon miktarı arasındaki ilişki incelenmiştir. Enjeksiyon miktarının kaya kütlesi özelliklerine göre değişimini daha detaylı görebilmek için her enjeksiyon deliği kendi içerisinde incelenmesi doğru bir yönlenme olacaktır. Bunun için enjeksiyon miktarlarının metraja bağlı olarak dağılımından faydalanılmalıdır. Fakat mevcut verilerin mesafeye göre homojen dağılmış olmaması ve aynı metrajlara denk gelmemesi sebebiyle öncelikle jeoistatistik yöntemi kullanılarak mevcut verilerin miktarı yüksek doğruluk oranıyla çoğaltılmış ve aynı metrajlara denk gelen veriler birbirleriyle ilişkilendirilmiştir. Böylece örnekleme çerçevesi arttırılarak daha detaylı inceleme gerçekleştirilebilmiştir. Bu sayede enjeksiyon delikleri ayrı ayrı değerlendirilerek Q değerleri ile enjeksiyon miktarları arasındaki ilişkiyi göstermek amacıyla çizilen grafikler incelendiğinde bu iki parametrenin eğilim çizgilerinin zıt yönde olduğu görülmüştür. Bu da kaya kütle kalitesi azaldıkça enjekte edilen enjeksiyon miktarının arttığını görsel olarak doğrulamaktadır.

Abstract:
For past few decades, demands in underground structures, what mainly is transport and energy industry, have increased because of economical, social and environmental causes in Turkey like other developing countries. This case makes tunneling become important issue.  Tunneling is the common work field for several disciplines such as geological, mining and civil engineering. 
Since 1990s population has increased in Istanbul due to immigration. It causes imbalance between demanding and supplying water. To solve this main problem, 'Melen Water Project' was created. With this project, the water of Melen River in Düzce where is 17 km far from Istanbul will be transported by steel pipes in underground. Thus, permanent solution will be made against public demands and seasonal droughts. 
The study field is Ayazağa Tunnel where is a part of 'SP-6  Cumhuriyet Terfi Deposu-Kağıthane Arası İsale Hattı' in 'Melen Water Project'. Ayazağa tunnel is a water conduit tunnel with a length of 2557m and a steel pipe diameter of 4m. Tunnel move upward by an inclination of 0.08% since it has 2m elevation between starting and ending points of tunnel. Overburden thickness of tunnel is 90m in average. Tunnel is projected by a final flow capacity with 32 m3/sec. (DSİ, 2010). 
Tunnel geologic units covered Devonian Kartal, Carboniferaus Thracian, Neogen Belgrad, Kuaterner Aluvional Formations as well as diabase and andesite dykes (Emiroğlu, 2010). 
New Austrian Tunnelling Method (NATM) was used for tunnel excavation and supports. Conventional drilling and blast method is selected for loosening and excavating rock. If the blasting method is not allowed, a hydraulic breaker is practiced for extracting weak formation. 
Q values were found out by recording data collected from face profiles by geologists. The Q classification is performed for the determination of rock classes, face penetration length in every cycle, maximum stand up times and, support type selection. A cross sectional view of face is drawn in a paper sheet. Then, all parameters related to calculate Q were filled out and evaluated on the paper as a report. Up to them, 5 different support types were fixed into tunnel perimeter and beyond. Steel pipes transferring water were inserted into tunnel after supporting process completed. After that, filling grouting was injected into the clearance between tunnel support and steel pipe. Moreover, by an aim at  stabilization on the geological environment that includes voids and cracks, consolidation grout application was performed between tunnel support and rock mass. While excavating it, geological and grouting data were recorded, and by using this data, the relationship between rock mass quality and amount of the grout volume was studied by geostatistical method (Tunçdemir & Kap, 2013).
In this study, consolidation grout applied for filling voids between tunnel support and geological formation is analysed geostatictically. A relation with grouting data and geological parameters are examined. Eventually, results are recorded in detail and evaluated for interpretation.
Main aim is to examine geological study, excavation, supporting, consolidation grouting application in Ayazağa tunnel, then to prove effects of rock mass parameters on grouting amount and choosing support type. Therefore, the results obtained in this study will be useful for the following projects in the future.
Past studies in same field are investigated to make researcher's view wider. For this study, there are some past studies is giving below:
Bieniawski (1989) stated that RMR rock mass classification value and tunnel supporting types have opposite relation because supporting type and quantity increase with decrease of rock mass quality. 
Another study by Grimstad and Barton (1993) shows that Q rock mass classification value and tunnel supporting types have opposite relation because supporting type and quantity increase with decrease of rock mass quality. 
Bahçivan (2011) also observed that rock mass quality and consolidation grouting have  obvious relation. To this study, this relation is opposite between Q rock mass classification value and grout amount injected rock mass, so grout amount increases with getting worse geological conditions. 
All these studies were examined in detail that causes drawing way to right direction for researcher. Hypothesis is whether consolidation grout amount depends on geological parameters and their relation is opposite. Grout amount injected into voids and cracks increases with a decrease quality of rock mass. The study and research were carried out with this view to prove hypothesis. 
At the beginning, a literature survey  carried out and previous studies were found out. Q rock mass quality classification, grouting methods, geology of study field, and geostatistical estimation was clearly documented. Necessary and avaliable data were collected and injection process in Ayazağa Tunnel were examined well by the help of the engineers of contractor company. 
Ayazağa Tunnel settles on kilometers between 20+586,96 and 18+009,91 of Melen Project. However, the data collected includes the kilometers between  20+583 and 20+229 , 19+389 and 18+256. In these kilometers, tunnel face profile maps and grouting reports were recorded. By geostatistical method, the data in hand were multiplied for an assesment with high accuracy, so that it is able to study in detail and accurately.
In study field, there are 589 grouting holes that were examined. For this area Q rock mass classification value changes between 0,25 and 0,027. It means geological conditions are very poor and extremely poor. Based upon analyses of records, it is shown that amount of the grout volume injected into the top holes of steel pipe was high. However, amount of grout volume in middle level of steel pipe is less than them and in the bottom of steel pipe is the least. This situation shows that rock mass loads tends to move down from crown to bottom of tunnel after excavation, this is because some spaces is experienced on the crown of tunnel. 
Geostatistical process was first proposed by Matheron in 1971 based on regionalized variable theory. It uses global x and y coordinates pointing out the areal variables. In these coordinates, whatever it is, a z parameter map is plotted by using known values coordinates. Geostatistical calculation actually focuses on evaluating values of points where its values are unknown from those where its values are known in a coordinated area. It is generally used for reserve estimation of underground mines from well logs. Besides, it was used in tunneling activities such as determination of settlement map of a sewerage tunnel in Istanbul (Tuncdemir et al. 2011). Numerous studies have emerged in various sciences so far.
In this thesis on Ayazağa conduit tunnel, 2D geostatistical analysis is performed for every drilling holes with respect to their x and y coordinates and their AIV Values by using Tercan & Saraç (1988) concept because Q values and hole coordinates are randomly intersected. By using 2D geostatistical estimation technique the number of AIV values can be multiplied and these new estimated values coordinates definitely overlap on Q values coordinates. Hence, one can compare and interpret same coordinated values.
Each grouting hole number has about 50 different grouting points and its datas. 50 datas could be increased to 1200 datas multiplied with geostatistical method. To prove the accuracy of this multiplication process, regression analysis was carried out between origin datas and multiplied datas. Regression graphics shows that most of correlation coefficients are very close to 1.  It proves that multiplication process was highly accurate. 
To observe the changes of consolidation grout volume to rock quality, the relation of consolidation grout between Rock Mass Quality Classification (Q) and Rock Quality Designation (RQD) was analysed. What the correct way to see this relation in detail is examining each injection hole separately. For that reason, distribution of grout data for all range is needed. However, because of inhomogeneous distribution of it and not to be Q and injection datas in same meters, geostatistic method was used. In this way, datas can be multiplied with high accuracy as much as needed. Then Q and injection datas get in same meters. Thus, it can be possible to examine in detail by spreading sample set. After all this process, it is shown that amount of consolidation grout has an inverse relationship between Rock Mass Quality Classification (Q) and Rock Quality Designation (RQD). It means that grout volume injected increases with a decrease on rock mass quality.
Moreover, examining injection holes seperately and putting data in Q and grout volume, trend lines of these two parameters shows opposite direction. It is visually stated that rock mass quality increases with a decrase on amount of grout volume.