Numerical Modelling of Entrance and Exit Portals in Pirinkayalar Tunnel (Erzurum, Turkey): A Case Study

Abstract

Rock mass classification systems are used to characterize the mechanical behavior of the rock mass, as well as suggestions for the support design to be used in tunnel excavation. In many tunnel projects from past to present, the support has been designed with the suggestions in the rock mass classification systems. Continuous monitoring of tunnel deformations and determination of support condition can be difficult and costly for practitioners. Pirinkayalar tunnel is one of the tunnels on the Artvin-Erzurum highway that connects Eastern Black Sea to Eastern Anatolia and the support system proposed with NATM (New Austrian Tunneling Method) was used. The support system planned at the project stage was changed again depending on the rock mass classification system during the excavation. Analysis of the excavation and preferred support system in the entrance and exit portals of tunnels prevent possible problems. In this study, the entrance and exit portals of the Pirinkayalar tunnel are modeled in 3D using the FLAC3D based on the finite difference method. With this case study, numerical modeling results, which are used as an auxiliary tool to obtain information about the state of the empirically designed support system in a tunnel, are mentioned.

Keywords

• Rock mass classification systems
• Excavation
• Numerical modelling
• Support design
• Tunnel

PİRİNKAYALAR TÜNELİ (ERZURUM, TÜRKİYE) GİRİŞ VE ÇIKIŞ PORTALLARININ SAYISAL MODELLENMESİ: ÖRNEK VAKA ÇALIŞMASI

Abstract

Kaya kütlesi sınıflama sistemleri kaya kütlesinin mekanik davranışını karakterize etmek için kullanılmasının yanı sıra tünel kazısında kullanılacak tahkimat tasarımı için de öneriler sunmaktadır. Geçmişten günümüze birçok tünel projesinde kaya kütlesi sınıflama sistemlerindeki önerilerle tahkimat tasarımı yapılmıştır. Tünel deformasyonlarının sürekli olarak izlenmesi ve tahkimat durumunun tespiti, uygulayıcılar için zor ve maliyetli olabilmektedir. Pirinkayalar tüneli Doğu Karadeniz’i Doğu Anadolu’ya bağlayan Artvin-Erzurum karayolu üzerindeki tünellerden biri olup tahkimat tasarımında NATM (Yeni Avusturya Tünel Açma Yöntemi) ile önerilmiş tahkimat sistemi kullanılmıştır. Proje aşamasında planlanan tahkimat sistemi kazı sırasında bazı bölgelerde yine kaya kütlesi sınıflama sistemine bağlı olarak değiştirilmiştir. Tünellerde giriş ve çıkış portallarının kazısı ve tercih edilen tahkimat sisteminin analizi muhtemel sorunların önlenmesini sağlayacaktır. Bu çalışmada, Pirinkayalar tünelinin giriş ve çıkış portalları sonlu farklar yöntemine dayalı olarak analiz gerçekleştiren FLAC3D programı kullanılarak 3 boyutlu olarak modellenmiştir. Gerçekleştirilen bu örnek vaka çalışması ile, bir tünelde ampirik yöntemle tasarlanan tahkimat sisteminin durumu hakkında bilgi edinmek için yardımcı araç olarak kullanılan sayısal modelleme sonuçlarına değinilmiştir.

Keywords

• Kaya kütlesi sınıflama sistemleri
• Kazı
• Sayısal modelleme
• Tahkimat tasarımı
• Tünel

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