تحلیل تئوریکی و عددی توده سنگ مچاله ‌شونده اطراف یک حفره کروی با در نظرگیری وجود ناحیه آسیب ‌دیده

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه تبریز، تبریز، ایران

چکیده

در صورتی که با استفاده از انفجار و مته‌زنی فضای زیرزمینی حفاری شود، ناحیه آسیب دیده‌ای در اطراف آن پدید می‌آید که خصوصیات مکانیکی و خزشی آن می‌تواند به شدت با توده‌ سنگ اولیه متفاوت باشد. وجود چنین ناحیه‌ای در توده‌ سنگ‌های مچاله شونده می‌تواند منجر به افزایش جابه‌جایی‌ها با گذشت زمان شود. از این رو، در این مقاله، یک حل تحلیلی بسته برای تعیین رفتار دراز مدت حفره کروی که در اطراف آن، یک ناحیه آسیب دیده وجود دارد، ارائه می‌شود. بدین منظور فرض می‌شود که رفتار توده سنگ از مدل برگر تبعیت می‌کند. بعد از صحت‌سنجی مدل، با استفاده از مطالعه پارامتریک، تأثیر عوامل مختلفی همچون شعاع حفره کروی، ضخامت ناحیه آسیب دیده، مدول برشی و ضریب ویسکوزیته مورد بررسی قرار می‌گیرد. نتایج این تحقیق حاکی از آن است که اگر شعاع ناحیه آسیب دیده ثابت در نظر گرفته شود، با کاهش شعاع حفره از 7 به 4/57 متر، جابه‌جایی دیواره حفره بلافاصله و بعد از مدت 10 سال به ترتیب 1/42 و 1/57 برابر می‌گردد. در مقابل، در صورتی که مقدار شعاع حفره برابر 4/57 متر باشد، بلافاصله و بعد از گذشت 10 سال، جابه‌جایی دیواره حفره کروی که شعاع ناحیه آسیب دیده برابر 8 متر است، به ترتیب 50% و 70% بیشتر از حالتی است که این شعاع برابر 6 متر است. با فرض ثابت بودن شعاع حفره کروی و شعاع ناحیه آسیب دیده، اگر مقدار ویسکوزیته کلوین یک بیستم گردد، جابه‌جایی دیواره حفره کروی بعد از گذشت 1 سال به ترتیب 115% و 173% افزایش می‌یابد. این در حالی است که اگر مقدار ویسکوزیته ماکسول این ناحیه 20 برابر گردد، بعد از گذشت 50 سال، این جابه‌جایی حدود 14 درصد کمتر می‌شود.
 

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Theoretical and numerical analyses of squeezing rock mass around a spherical opening considering the existence of a damaged zone

نویسندگان [English]

  • Milad Zaheri
  • Masoud Ranjbarnia
Department of geotechnical Engineering, Faculty of civil engineering, University of Tabriz, 29 Bahman Blvd, Tabriz, Iran
چکیده [English]

If an underground opening is excavated using the drill and blast method, an excavation damaged zone (EDZ) will appear around the opening in which it's mechanical and creep properties can be very different from the initial rock mass. The existence of such a zone in squeezing rock masses can lead the time-dependent displacements to increase. Therefore, in this paper, a closed-formed analytical solution is proposed to determine the long-term performance of a spherical opening surrounded by an EDZ. To consider the time-dependent behavior, the viscoelastic Burgers model is assigned to the rock mass. After verifying the proposed method, a parametric study is performed and the influence of various factors such as the radii of the opening and EDZ, the shear modulus, and the viscosity of rock mass are investigated. It is found that if the EDZ radius is considered constant, the displacement of the cavity with 7 meters radius, immediately and after 10 years, is respectively 1.42 and 1.57 times greater than the case in which the cavity radius is 4.57 meters. On the other hand, if the cavity radius is equal to 4.57 meters, immediately and after 10 years, the displacement of the cavity wall in which the EDZ radius is 8 meters is respectively 50% and 70% greater than the case in which this radius is equal to 6 meters. When the radii of the cavity and the EDZ are constant, if the Kelvin viscosity becomes one-twentieth, the cavity displacement increases by 115% and 173% after 1 year, respectively. However, if 20 times of the initial Maxwell viscosity of the EDZ is used in the calculations, this displacement decreases by about 14%, after 50 years.

کلیدواژه‌ها [English]

  • Analytical modeling
  • Underground opening
  • Burgers model
  • Time-dependent behavior
  • Squeezing rock mass

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نشریه مهندسی عمران امیرکبیر
دوره 54، شماره 11
بهمن 1401
صفحه 4215-4238

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