مدل سازی سه بعدی پایداری و تغییر شکل جبهه کار تسلیح شده و تسلیح نشده در تونلهای کم عمق

نوع مقاله : مقاله پژوهشی

نویسندگان

1 باشگاه پژوهشگران جوان و نخبگان، دانشگاه آزاد اسلامی- واحد تهران جنوب، تهران.

2 گروه مهندسی ژئوتکنیک، دانشکده فنی و مهندسی، دانشگاه آزاد اسلامی- واحد اسلامشهر، اسلامشهر.

10.22091/cer.2020.4950.1182

چکیده

اقدامات پیش‌تحکیمی در تونل‌زنی در شرایط کم‌عمق و مشکل‌دار یکی از راهکارهای موفق در عملیات حفاری و تحکیم تونل‌هاست. استفاده از نیل فایبرگلاس در جبهه کار تونل به‌عنوان یکی از روش‌های مؤثر و اقتصادی پیش‌تحکیمی برای افزایش پایداری و کنترل نشست در زمین‌های نرم است. در این مطالعه، مدل‌سازی سه‌بعدی اثرات نیل فایبرگلاس در جبهه کار در کاهش پدیده شکم‌دادگی، نشست قائم و ضریب ایمنی با دو روش مدل‌سازی مستقیم نیل در مدل سه‌بعدی اجزای محدود و مصالح با مقطع معادل، بررسی شده است. مطالعه حاضر، اثرات دانسیته نیل، نسبت عمق به قطر تونل (C/D) و گام پیشروی را بررسی می‌کند. از روش کاهش مقاومت برای محاسبه ضریب ایمنی تونل استفاده شده است. نتایج تحلیل عددی با روش‌های تعادل حدی برای تعیین ضریب ایمنی مقایسه گردیده است. مقایسه روش تعادل حدی با روش اجزای محدود نشان می‌دهد که استفاده از نیل فایبرگلاس، ضریب ایمنی تونل را بین 50 تا 75 درصد (به ازای 20 نیل فایبرگلاس) و 125 تا 200 درصد (به ازای 50 نیل فایبرگلاس) با توجه به نسبت عمق به قطرهای مختلف افزایش می‌دهد. این در حالی است که با افزایش گام پیشروی، مقدار جابه‌جایی قائم در هر دو روش، افزایش می‌یابد ولی تأثیری در مقدار جابه‌جایی افقی تونل در هر دو روش ندارد. همچنین استفاده از نیل در جبهه کار تونل، مقدار جابه‌جایی قائم را بین 20 تا 35 درصد و جابه‌جایی افقی را بین 50 تا 60 درصد کاهش می‌دهد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

3D Modeling of Stability and Deformation of Reinforced and Unreinforced Face in the Shallow Tunnel

نویسندگان [English]

  • Majid Taromi 1
  • Amir Hossein Eghbali 2
  • Navid Hadiani 2
1 Young Researchers and Elite Club, South Tehran Branch, Islamic Azad University, Tehran, Iran
2 Department of Civil Engineering, Islamic Azad University Islamshahr Branch, Tehran, Iran.
چکیده [English]

Utilizing of fiberglass nail in the face of tunnel is one of the economical and effective pre-support methods for increasing stability and control of settlement in weak grounds and tunnels with extended level and increase of ground mechanical strength. In this study, by taking advantage of 3D modeling of fiberglass nail which is effective in reduction of deformation, settlement, the direct modeling of nail in the 3D finite element and material with equivalent section. This study has covered effects of nail density, the overburden to depth of tunnel ratio. The method of strength reduction for analyzing the safety factor of tunnel has been considered. The result of 3D numerical analysis with limit equilibrium methods (LEM) for determining safety factor has been compared. The comparison of LEM and finite element method revealed that using of nail fiberglass and increases the range of safety factor between 5% to 75% and 1.25 to 2 in terms of overburden to diameter ratio. This increase of nail is dependent on density and overburden. While, with increase to advance length, the amount of vertical displacement would rise in both method, although these measures have no effects in horizontal displacement. In addition to that, using of nail in the tunnel face has caused the amount of vertical displacement between 20 to 35 percent and in the horizontal displacement between 50 to 60 percent of decrease has happened.

کلیدواژه‌ها [English]

  • Safety factor
  • Deformation
  • LEM
  • Fiberglass nail
  • 3D modelling

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