مدلسازی عددی تقاطع غیر هم‌سطح تونل های حفاری شده به روش مکانیزه

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود

2 دانشکده مهندسی عمران، دانشگاه صنعتی شاهرود

3 دانشکده مهندسی معدن، دانشگاه تهران

10.29252/anm.8.16.29

چکیده

با افزایش روز افزون سازه­های زیرزمینی، احداث این سازه­ها در مجاورت یکدیگر به ویژه ساخت یک تونل جدید در نزدیکی تونل پیشین در محیط‌های شهری امری اجتناب ناپذیر خواهد بود. در بخشی از مسیر احداث قطعه شرقی- غربی تونل خط 7 متروی تهران، ماشین حفاری مکانیزه با فاصله 25/2 متر از بالای تونل انتقال پساب ابوذر عبور می­کند. در مقاله حاضر جهت بررسی اندرکنش بین دو تونل، مدلسازی عددی سه‌بُعدی با استفاده از نرم‌افزار FLAC3D انجام شده است. به این منظور ابتدا فرایند حفاری مکانیزه تونل ابوذر مدلسازی شده، سپس اثر حفر مرحله­ای تونل متروی خط 7 بر سیستم نگهداری تونل ابوذر بررسی شده است. تاریخچه تغییرات نیروهای داخلی، لنگرهای خمشی و تغییر مکان‌های سازه پوشش تونل ابوذر ارائه شده و مورد بررسی قرار گرفته است و توصیه­های مهندسی در تحلیل تونل­های متقاطع غیر هم­سطح ارائه شده است. نتایج حاصل از مدلسازی نشان می­دهد که پس از حفاری تونل مترو، سیستم نگهداری تونل ابوذر به دلیل افزایش ناحیه پلاستیک و آزاد سازی تنش، به سمت بالا جابجا خواهد شد. این جابجایی سبب ایجاد نیروهای داخلی بیش از مقادیر مجاز طراحی شده در لاینینگ تونل ابوذر خواهد شد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical investigation of mechanized shield tunnels cross-cut

نویسندگان [English]

  • Seyed Saeed Hosseini 1
  • Seyed Mohammad Esmail Jalali 1
  • Meysam Jalali 2
  • Emad Khorasani 3
1 Dept. of Mining, Geophysics & Petroleum Shahrood University of Technology, Iran
2 Dept. of Civil Engineering, Shahrood University of Technology, Shahrood, Iran
3 Dept. of Mining, University of Tehran, Iran
چکیده [English]

Summary
In parts of constructing east-west section of line7 Tehran subway, the excavating machine (EPB-TBM) passes from the top of the Abouzar’s wastewater conveyance tunnel with clear distance of 2.25 m. The FLAC 3D has been used to model this problem and find the deformations and forces of ground and linings. The modeling results showed that after excavating subway tunnel, lining of Abouzar tunnel will move upward due to the increasing plastic zones and stress relaxation. This rate of displacement induced the internal force more than allowable designed amount in concrete lining of Abouzar tunnel.
 
Introduction
Generally, excavating a tunnel near another tunnel may lead to significant interaction effects, which mainly depends on tunnels position relative to each other (parallel or cross), the distance between two tunnels, tunnel dimensions, lining rigidity, stress and boring environment condition as well as the method of tunnel boring. The interaction between adjacent tunnels have been investigated by different researchers using methods such as analytical and empirical, field observation, physical modeling and numerical modeling. In the current project, the tunnel of Tehran metro line7 passes with a distance of 2.25 meters from the top of the Abouzar tunnel. Because of the three-dimensional nature of the interaction problem between underground spaces, numerical modeling is an appropriate tool for the analysis of these complicated problems. Therefore, FLAC3D software has been used in order to investigate the interaction analysis. The purpose of modeling is to study stability of support system of Abouzar tunnel during tunnel excavation of Tehran metro line7.
 
Methodology and Approaches
In this paper, the finite difference method (FDM) is used for modeling and solving the problem. FLAC 3D program which uses FDM was selected in order to study the interaction between the two tunnels, in construction stage. For this purpose, at first Abouzar tunnel modeled and excavated, then impact of stepwise excavating of line7 Tehran subway on lining system of Abouzar tunnel is investigated numerically. History of Internal forces, bending moments and structural displacement of Abouzar’s tunnel lining have been provided and studied. Engineering recommendations have been proposed in different-leveled intersecting tunnels.
 
Results and Conclusions
The results of the modeling showed that after excavation of metro tunnel, the support system of Abouzar tunnel will be uplifted because of increasing plastic zone and stress relaxation. This displacement causes internal forces in Abouzar tunnel lining which are more than allowed values.

کلیدواژه‌ها [English]

  • Tunnels cross-cut
  • Tunnels interaction
  • Tehran Metro L7
  • Abouzar Tunnel
  • Stability analysis of tunnel linings
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