نویسندگان

دانشکده مهندسی معدن، دانشگاه صنعتی اصفهان، اصفهان

چکیده

پایداری دینامیکی و روانگرایی سدهای باطله یکی از معضلات ژئوتکنیکی است که از دیرباز محققان این حوزه را به چالش کشیده است. در این مطالعه پاسخ لرزه‌ای سد باطله معدن فسفات اسفوردی واقع در منطقه لرزه‌خیز بافق استان یزد مورد بررسی قرارگرفته است. به این منظور از کد تفاضل محدود فلک (Flac2D) و به‌کارگیری دو مدل رفتاری موهر- کلمب و فین- بایرن برای مدل‌سازی بهره گرفته ‌شده است. به‌منظور محاسبه و تعیین مناطق مستعد روانگرایی و یا روانگرا شده کدنویسی به‌صورت تابع فیش در نرم‌افزار انجام می‌شود. جابه‌جایی‌های افقی و قائم (نشست) در بدنه سد، فشار منفذی اضافی، نواحی شکست و روانگرایی ناشی از بار لرزه‌ای با استفاده از دو مدل رفتاری انتخاب‌شده، تحت زلزله 6/4 ریشتری که در سال 1383 در یزد اتفاق افتاد، تعیین ‌شده‌اند. بیشینه جابه‌جایی افقی در پایین‌دست بدنه سد با توجه به مدل رفتاری موهر- کلمب و فین- بایرن به‌ترتیب 5 و 35 سانتی‌متر مشاهده ‌شده است. همچنین نشست حاصل از این بار لرزه‌ای در بالادست تاج سد، با استفاده از دو مدل رفتاری تعیین‌شده، به‌ترتیب 4 و 23 سانتی‌متر مشاهده ‌شده است. نسبت فشار آب منفذی اضافی (ru)، در دو مدل رفتاری استفاده‌ شده، کمتر از حد روانگرایی (0/8) به‌دست‌آمده که حداکثر مقدار آن 0/7 برای مدل رفتاری فین- بایرن و 0/2 برای مدل رفتاری موهر- کلمب به‌دست‌آمده است. به‌طور کلی نتایج نشان می‌دهند که با توجه به در نظر گرفتن تأثیر تجمعی توالی بار لرزه‌ای در مدل رفتاری فین– بایرن، این مدل رفتاری درک بهتری از پدیده روانگرایی را ارائه می‌دهد.

کلیدواژه‌ها

عنوان مقاله [English]

Finite Difference Dynamic Stability and Liquefaction Analysis of Esphordi Mine Tailings Dam Implementing Non-Linear Elasto-Plastic Constitutive Model

نویسندگان [English]

  • R. Salamat Mamakani
  • A. Azhari

چکیده [English]

Dynamic stability and liquefaction of tailings dams are great concerns for geotechnical engineers. In this study, the seismic response of the Esphordi mine tailing dam located in Bafgh seismic region of Yazd province is investigated. A finite-difference code (FLAC2D) is used to model the seismic liquefaction applying two constitutive criteria, namely Mohr-Coulomb and Finn-Byrne. For this purpose, a fish function is implemented into the code to simulate the non-linear elasto-plastic Finn-Byrne constitutive model. Horizontal and vertical displacements (subsidence) in the dam body, additional pore pressure, failure zones, and liquefaction due to seismic load were determined using the two selected criteria under the seismic load of the 6.4 magnitude earthquake occurred in 2005. Considering the type of behavioral model, Mohr-Coulomb and Finn-Byrne, the maximum horizontal displacement of 5 and 35 cm in the dam body and downstream, and subsidence of 4 and 23 cm at the dam crest and upstream are observed, respectively. Also, the calculated ratio of excess pore pressure (Ru), for both criteria, was less than the liquefaction limit (0.9), the maximum value of which was 0.7 for the Finn-Byrne criterion and 0.2 for the Mohr-Coulomb criterion. In general, the results show that considering the cumulative effect of the seismic load cycles in the Finn- Byrne model, this criterion provides a better understanding of the liquefaction phenomenon.

کلیدواژه‌ها [English]

  • Mine Tailings Dams
  • Liquefaction
  • Mohr-Coulomb
  • Finn-Byrne
  • Finite-Difference Numerical Method
  • Dynamic analysis
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