Zayıf ve Sıkışan Kaya Kütlesinde Açılan Bir Tünel için Rijit Destek Sistemi Çözümü (T34-GT2 Tüneli, Ankara-İstanbul YHT Projesi)

Abstract

Bu çalışmaya konu olan T34-GT2 Tüneli, 4,5 m genişliğinde 5 m yüksekliğinde olup, Ankara-İstanbul Hızlı Tren Projesi kapsamında T34 Tünelinde (km: 229+360-231+578) yolcu güvenliğini sağlamak amacıyla inşaa edilmiştir. Tünel 25 m uzunluğunda ve tamamı Karbonifer-Permiyen yaşlı meta-kırıntılı birimler içindedir. Tünel yaklaşık 650 eğimli normal fay tarafından kesilmektedir. Bu fay boyunca bir zon olarak zayıf ve sıkışan kaya özelliğinde meta-kırıntılılar bulunmaktadır. Bu tür kaya ortamları, tünel destek sistemi tasarımı açısından kritik öneme sahiptir. Benzer kaya koşullarında açılan tünellerde ayna ve tavan stabilite sorunlarının yanında ciddi deformasyonların olduğu bilinmektedir. Bu nedenle bu çalışmada tünelcilik açısından özel problemler içeren T34-GT2 Tünelinde bulunan fay zonuna odaklanılmış en uygun destek sisteminin analizlerle ortaya konulması amaçlanmıştır. Bu amaçla tünelin sıkışma potansiyeli belirlenmiş, hızlı kazı, güçlü destek, düşük deformasyon prensiplerine dayanan rijit destek sistemi tasarlanmıştır. Tasarlanan destek sistemi sayısal analiz yöntemleri kullanarak detaylandırılmış ve elde edilen sonuçlar tünel kazı ve destek aşamalarında dikkate alınmıştır. Ardından analiz sonuçları tünelde gerçekleşen deformasyonlarla kıyaslanmıştır. Sonuç olarak, sayısal analizler ile tünelde gerçekleşen deformasyonların birbirine yakın olduğu ve önerilen rijit destek sisteminin benzer kaya koşullarında uygulanabilir bir yaklaşım olduğu belirlenmiştir.

Keywords

• Sayısal analiz
• Sıkışma
• Tünel güvenliği
• Zayıf kaya

Rigid Support System Solution for a Tunnel in Weak and Squeezing Rock Mass (T34-GT2 Tunnel, Ankara-Istanbul YHT Project)

Abstract

The T34-GT2 Tunnel, the subject of this study, is 4.5 m wide and 5 m high and was constructed within the scope of the Ankara-Istanbul High Speed Train Project to ensure passenger safety in the T34 Tunnel (km: 229+360-231+578). The tunnel is 25 m long and is entirely located within the Carboniferous-Permian metaclastic units. The tunnel is istersected by a normal fault with an inclination of approximately 650. There are metaclastics with weak and squeezing rock characteristics along the fault zone.It is known that there are serious deformations in addition to face and roof stability problems in tunnels excavated under similar rock conditions. Therefore, this study focuses on the fault zone in the T34-GT2 Tunnel, which has special problems in terms of tunneling, and aims to reveal the most suitable support system with analyses. For the purpose of the study, the squeezing potential of the tunnel was determined and a rigid support system based on the principles of fast excavation, strong support, and low deformation was designed. The designed support system was detailed using numerical analysis methods and the obtained results were considered during the tunnel excavation and support stages. Then, the analysis results were compared with the deformations in the tunnel. As a result, it was determined that the deformations in the tunnel were close to each other with the numerical analysis and the proposed rigid support system was an applicable approach in similar rock conditions.

Keywords

• Numerical analysis
• Squeezing
• Tunnel safety
• Weak rock

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