ارزیابی پایداری تونل انتقال آب ارومیه با مدل‌سازی عددی سه بعدی با استفاده از روش های اجزاء و تفاضل محدود

نوع مقاله: یادداشت فنی

نویسندگان

1 کارشناس ارشد ژئوتکنیک؛ دانشکده‌ی مهندسی عمران، دانشگاه علم و صنعت ایران

2 دانشیار؛ دانشکده‌ی پدافند غیر عامل، دانشگاه امام حسین (ع)

10.22044/tuse.2019.7499.1349

چکیده

تونل انتقال آب گلاس (کانی سیب) به‌منظور هدایت آب مازاد رودخانه­ی گلاس به حوضه آبریز دریاچه ارومیه و دشت نقده و تأمین آب زراعی بخش عمده­ای از این اراضی است. در مسیر تونل قسمت آبرفت با طول تقریبی 1800 متر وجود دارد که به لحاظ ژئوتکنیکی دارای شرایط خاصی است. مدل‌سازی این تونل به روش­های NATM و مکانیزه با استفاده از نرم‌افزارهای FLAC3D وPLAXIS 3D TUNNEL  انجام و نتایج با یکدیگر مقایسه شد. نتایج به‌دست‌آمده نشان داد که پایداری قسمت آبرفت با استفاده از روش­های حفاری NATM و ترکیب با روش­های بهسازی، تأمین نمی­شود. جهت صحت‌سنجی، طول کوتاهی از تونل در آبرفت حفاری شد که به علت ناپایداری شدید و خطر ریزش تونل ادامه حفاری در آبرفت متوقف شد. با مدل‌سازی روش مکانیزه در دو نرم‌افزار فشار سینه کار برابر 9 بار به‌عنوان فشار تعادل محاسبه شد. همچنین در این فشار حداکثر جابه­جایی جبهه حفاری در دو نرم‌افزار 6 تا 7 سانتیمتر به دست آمد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of Urmia Tunnel Stability using 3D Finite Element and Finite Difference Modeling

نویسندگان [English]

  • soheil sharifi 1
  • fereydoon khosravi 2
  • seyed rasoul sourani 1
1 M.Sc. Student in Geotechnical Engineering, Iran University of Science and Technology
2 Assistant Professor; Faculty of Civil Engineering, Imam Hossein University
چکیده [English]

Summary
Urmia tunnel is being constructed to convey water to the Naghadeh and Urmia agricultural plains. About 1800 m of excavations are located in the alluvial ground. In this paper, a part of Urmia tunnel that is located in the alluvial ground was modeled using the numerical modeling FLAC3D and PLAXIS3D TUNNEL software packages. For this, first, the new Austrian tunneling method (NATM) was modeled. The NATM modeling results showed high displacement and instability of the face of the tunnel. Then, the earth pressure balance (EPB) machine was modeled and the face pressure was calculated. The modeling results showed suitable conformation between the two software packages. Moreover, a short-length part of the tunnel was excavated in the alluvial structure using the NATM, however, according to the modeling results, the face of the tunnel was unstable, and thus, the excavation was stopped. The face pressure, in the tunnel boring machine(TBM) was also calculated.
 
Introduction
Urmia tunnel is a challenging project because of its especial ground and excavation conditions. The main focus of this research is on tunneling in hard conditions like high groundwater level, high depth of tunnel, too much overburden, etc. An example of tunneling in hard conditions is the Urmia tunnel that is studied in this paper. The main objective of this paper is to select a suitable method of excavation in the tunnel.
 
Methodology and Approaches
In this study, the NATM and its combination with soil improvement methods, and also, the EPB machine were modeled using the numerical modeling FLAC3D and PLAXIS 3D TUNNEL software packages. A short-length part of the tunnel, which was excavated in the alluvial ground using the NATM, was considered in this study.
 
Results and Conclusions
The obtained modeling results in this study showed high displacement of both face and crown and instability of the face in the NATM modeling and combination of the NATM and soil improvement methods like jet-grouting and forepoling. Thus, the EPB machine was modeled and the face pressure was calculated.

کلیدواژه‌ها [English]

  • Tunnel
  • Tunneling in Alluvial Ground
  • underground space
  • New Austrian Tunneling Method (NATM)
  • Jet Grouting
  • TBM
  • ADECO