تأثیر هندسه هسته ناتراوای سدهای خاکی در ضریب اطمینان شکست هیدرولیکی

نوع مقاله : یادداشت پژوهشی

نویسندگان

دانشکده فنی و مهندسی، دانشگاه خوارزمی، تهران

چکیده

هسته سدهای خاکی نه تنها در آب ­بندی سد، بلکه در احتمال رخداد شکست هیدرولیکی نقش مهمی دارند. بنابراین انتخاب ابعاد و نوع مصالح برای هسته سدهای خاکی بسیار مهم است. در تحقیق حاضر، هدف بررسی پدیده شکست هیدرولیکی و تأثیر ابعاد و شکل مقطع هسته رسی یک سد خاکی و محاسبه ضریب اطمینان در برابر شکست هیدرولیکی است. برای این منظور ابتدا با استفاده از مدل اجزای محدود به بررسی پدیده شکست هیدرولیکی در دو مقطع وسط هسته و وجه بالادست هسته برای دو نوع مصالح قرضه CL و CH پرداخته شده است. تحلیل ­ها در مراحل پایان ساخت، آبگیری اولیه و تراوش پایدار صورت گرفته و همچنین در مدل­سازی­ ها مراحل ساخت سد نیز در نظر گرفته شده است. نتایج نشان می ­دهد که خاک CL به ­عنوان خاک بحرانی و خاک CH به­ عنوان خاک منتخب برای استفاده در هسته سد است. همچنین احتمال وقوع شکست هیدرولیکی در هسته­ های ضخیم­ تر و کف هسته نیز بررسی گردید. نتایج نشان داد معیارهای فوکوشیما و قنبری به­ ترتیب خوشبینانه­ ترین داده ­ها و محافظه­ کارانه ­ترین داده ­ها را دارا می‌باشد. با توجه به معیارهای به کار گرفته شده در تحقیق حاضر، خاک CH در برابر شکست هیدرولیکی ایمن بوده و احتمال وقوع شکست هیدرولیکی برای خاک بحرانی (CL) در نقاطی از پایین­ دست هسته سد محتمل تشخیص داده شد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of Dimensions and Shape of Clay Core Section of Earth Dams on Reliability Coefficient of Hydraulic Failure

نویسندگان [English]

  • Mostafa Zalnejad
  • Seyed Shahab Emamzadeh
Faculty of Civil Engineering, University of Kharazmi, Tehran, Iran
چکیده [English]

Hydraulic fracturing can occur in the fine-grained core of earthen dams. This phenomenon often occurs during the first water intake of the dam when the water pressure suddenly increases. Hydraulic fracturing in Erath dam has investigated laboratory by many researchers (Jaworski, 1981; Jian, 2022; Patel, 2017). In this research, the aim is to investigate numerically the phenomenon of hydraulic fracture and the effect of the dimensions and shape of the clay core section of the Hajiler Chai Dam (an earthen dam with impermeable clay core) located in East Azarbayjan province on the reliability coefficient of hydraulic fracture. For this purpose, first, using Geo-Studio, the phenomenon of hydraulic fracturing has been investigated in two sections in the middle of the core (A-A) and the upstream side of the core (B-B) of the dam for two types of materials CL and CH. Analyzes have been done in the stages of the end of construction, initial dewatering and steady state seepage, and the stages of dam construction have also been considered in the modeling. Also, the possibility of hydraulic fracture in thicker cores and the bottom of the core was also investigated. Finally, the reliability coefficient of hydraulic failure occurrence has been quantitatively calculated for each of the soils in stages and sections and with different criteria, and the suitable soil has been suggested for use in the dam core.

کلیدواژه‌ها [English]

  • Earth dams
  • Hydraulic fracturing
  • Finite element
  • Impermeable core
  • Seepage
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