آنالیز عدم قطعیت برآورد حجم رسوب مخازن (مطالعه موردی سد شهرچای)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دوره دکترا /سازه‌های آبی، گروه مهندسی آب، دانشگاه تربیت مدرس، تهران، ایران

2 دانشیار /گروه مهندسی آب، دانشگاه تربیت مدرس، تهران، ایران

3 استادیار / گروه مهندسی آب، دانشگاه ارومیه، ارومیه، ایران

چکیده

پیش بینی مقدار رسوبات ورودی به مخازن سدها و نحوه توزیع و تجمع آن دارای اهمیت و پیچیدگی بالایی در طرح و بهره‌برداری مناسب چنین سازه‌های آبی است. روشهای ریاضی و تحلیلی متعدد و پیچیده‌ای برای شناخت فرآیند رسوب و برآورد رسوبات ورودی و نحوه رسوبگذاری آن در مخازن سدها ارائه گردیده است.  تحلیل رسوب در مخازن سدها بر اساس چنین روش‌هایی همواره توام با خطای نسبی بوده که این برآورد خطای نسبی به عنوان  Uncertainty (عدم قطعیت) در علوم مهندسی شناخته می‌شود. وجود عدم قطعیت در بر آورد پارامترهای طراحی سازه‌های آبی، یکی از دلایل اصلی عدم موفقیت مورد انتظار چنین سیستم‌هایی بوده و به کمیت درآوردن منابع عدم قطعیت می‌تواند یک گام اولیه و اصلی در تجزیه و تحلیل قابلیت اطمینان در عملکرد یک سازه آبی باشد. در طرح سیستم مخازن ذخیره (سدها)، تحلیل رسوب ورودی به مخزن جهت برآورد حجم مرده سد و نحوه ته نشینی رسوبات در سد از معیار‌های اساسی طراحی به شمار رفته و منابع خطا یا عدم قطعیت در چنین تحلیلی می‌تواند ناشی از عدم امکان پیش بینی قطعی جریان ورودی، میزان رسوب، نوع رسوب و .... به مخزن باشد. در این تحقیق از روش‌هار (Harr)  جهت تعیین میزان عدم قطعیت رسوبات متراکم شده مخزن در طول زمان (15، 30 و 45 سال بعد از بهره برداری) در کل دوره آماری و دوره آماری خشک و تر استفاده شده است،  به علاوه آنالیز حساسیت برای تعیین اهمیت فاکتور‌های مختلف عدم قطعیت رسوبات مخزن انجام گرفته است. در این مطالعه سیستم مخزن ذخیره شهرچای در منطقه آذربایجان غربی مورد بررسی قرار گرفته و عدم قطعیت رسوبات تراکمی مخزن و تأثیر هر فاکتور عدم قطعیت روی رسوبات تجمعی مخزن در دو دوره آماری ذکر شده به دست آمده است. نتایج نشان می‌دهد دبی سالیانه جریان و بار رسوب از مهمترین فاکتور‌های تعیین کننده عدم قطعیت حجم رسوبات سالانه مخزن و درصد رسوبات و راندمان تله اندازی دارای اهمیت کمتری می‌ باشند. همچنین در این روش عدم قطعیت رسوبات تراکمی مخزن در کل دوره آماری 384/0 و در دوره آماری خشک و تر 244/0 به دست آمده است.

کلیدواژه‌ها


عنوان مقاله [English]

Uncertainty Analysis of Reservoir Sedimentation With Harr's Method Case Study: Shahar Chai Dam In Iran

نویسندگان [English]

  • M Vaez Tehrani 1
  • J M. Samani 2
  • M Montaseri 3
1 pH.D student of Water Structures Eng., Tarbiat Modarres University, Tehran, Iran
2 Associate Professor of Water Structures Eng., Tarbiat Modarres University, Tehran, Iran
3 Assistant Professor of Water Structures Eng., Urmia University, Urmia, Iran.
چکیده [English]

One of problems that affects the hydro-installation and reduces the useful life of dams, is sedimentation in the reservoir, which is unavoidable. In estimating reservoir sedimentation and accumulation, a number of uncertainties arise. These are related to the quantity of streamflow, sediment load, sediment particle size, and specific weight, trap efficiency, and reservoir operation. To evaluate suspended sediments and bed load in some hydrometric stations, separating the field data into wet and dry time periods and total time periods are used. Harr’s method is used to quantify the uncertainty of accumulated reservoir sedimentation through time. To examine the importance of various factors on the uncertainty of accumulated reservoir sedimentation, sensitivity analysis was conducted. In this study, the effect of each uncertain factor, on the uncertainty of accumulated reservoir sedimentation through time has been examined for Shahar Chai Dam in northwestern Iran. The results show that in Harr’s method, the uncertainty of accumulated reservoir sediment volume is 0.384 in total time periods and 0.244 for wet and dry time periods.



 

 

کلیدواژه‌ها [English]

  • Reservoir Sedimentation
  • Harrs method
  • Uncertainty analysis
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