Fay Zonu İçinde Açılan Büyük Çaplı Bir Tünelin Kısa ve Uzun Dönem Zemin Parametrelerine Göre Davranışının ve Destek Sistemlerinin Değerlendirilmesi (T36 Tüneli, Ankara-İstanbul Yüksek Hızlı Tren Projesi)

Support system design has always been a critical engineering problem for large-scale tunnels excavated within fault zones. In fault zones, it is possible to encounter face and ceiling stability problems encountered during the tunnel excavation in the short term and failures in the support systems due to squeezing in the long term. For this reason, when designing support systems, short-term and long-term parameters should be considered. The most important factors in selecting the support system to be installed are to describe the geological conditions well and the correct selection of geotechnical design parameters. Therefore, the main purpose of this study is to investigate Yazışma Yazarı / Correspondence: cgokce@hacettepe.edu.tr Jeoloji Mühendisliği Dergisi / Journal of Geological Engineering 45 (2021) 1-28 DOI 10.24232/jmd.935374 Fay Zonu İçinde Açılan Büyük Çaplı Bir Tünelin Kısa ve Uzun Dönem Zemin Parametrelerine Göre Davranışının ve Destek Sistemlerinin Değerlendirilmesi (T36 Tüneli, Ankara-İstanbul Yüksek Hızlı Tren Projesi) Evaluation of Behavior and Support Systems based on Short and Long Term Soil Parameters of a Large Diameter Tunnel Excavated in Fault Zone (T36 Tunnel, Ankara-Istanbul High Speed Train Project) Ebu Bekir AYGAR1 , Candan GOKCEOGLU2 1 Fugro Sial Yerbilimleri Danışmanlık Mühendislik Ltd., Çankaya, Ankara 2 Hacettepe Üniversitesi, Jeoloji Mühendisliği Bölümü, Beytepe, Ankara Geliş (Received): 30 Ağustos (August) 2020, Düzeltme (Revised): 21 Eylül (September) 2020, Kabul (Accepted): 02 Kasım (November) 2020 Aygar, Gokceoglu Fay Zonu İçinde Açılan Büyük Çaplı Bir Tünelin Kısa ve Uzun Dönem Zemin Parametrelerine Göre Davranışının ve Destek Sistemlerinin Değerlendirilmesi 2 the support design that considers the shortand long-term parameters for the Ankara-Istanbul High Speed Train Project, T36 tunnel excavated within the fault zone. The total length of the T36 tunnel is 4100 m, and excavation and support works have been completed under a maximum overburden thickness of 180 m. In the fault zone transition, the supports were made under the overburden thickness of 115 m, and face stability problems were encountered in the short term and squeezing problems in the tunnel in the long term. In this study, the causes of deformations in the tunnel affecting the tunnel in the short and long term are discussed and numerical analysis and support systems are examined. Moreover, the criteria for fault zone crossings, which is one of the most important issues for tunneling, are discussed.