بررسی پایداری کناری و فرسایش پنجه‏ای ناشی از جریان سطحی با استفاده از مدل BSTEM (مطالعۀ موردی: رودخانۀ بشار)

نوع مقاله : پژوهشی

نویسندگان

1 دانشجوی دکتری آبخیزداری دانشگاه هرمزگان

2 استاد دانشکدۀ محیط زیست دانشگاه تهران

3 عضو هیئت علمی آبخیزداری دانشگاه هرمزگان

4 سازمان جنگل‏ها و مراتع و آبخیزداری کشور

چکیده

یک نیاز حیاتی برای مدیریت رودخانه، درک و پیش‏بینی فرسایش کناره‏ای است. بیشتر مدل‏های موجود؛ فرسایش کناره‏ای را به‏طور صریح بررسی نمی‏کنند. مدل BSTEM از پرکاربرد‏ترین مدل‏های استفاده‌شده در بسیاری از پروژه‏های مهندسی رودخانه در دنیا‌ست. داده‏های مورد نیاز برای این مدل مختص به نیروهای کمی محرک و مقاوم‌کنندۀ کنارۀ رودخانه است که فرایندهای هیدرولیک و ژئوتکنیک را که روی بانک وارد می‏شود کنترل می‏کنند. داده‏های مورد نیاز شامل داده‏های ژئومتری، هیدرولیکی و ژئوتکنیکی است. این داده‏ها با نمونه‏برداری، اندازه‏گیری میدانی و بررسی آزمایشگاهی به‏دست آمدند. نتایج مدل‏سازی در مقاطع بررسی‌شده نشان داد که در مقایسۀ بین مقاطع دارای پوشش و فاقد پوشش تفاوت شایان توجهی از نظر پایداری مشاهده شده است. میزان ضریب ایمنی در مقاطع فاقد پوشش کمتر از 1 بوده است که بیانگر ناپایداری کنارۀ رودخانه در این مقاطع است. در میان مقاطع دارای پوشش تنها مقطع 3 در رگبار 4 ‌ضریب ایمنی کمتر از 1 داشته است که از لحاظ میزان پایداری، ناپایدار بوده است. مقایسۀ مقاطع بررسی‌شده از نظر فاکتور ایمنی نشان داده‏اند که ناپایدارترین بازه‏ها به‌ترتیب مقاطع 5، 6، 8، 7، 3، 1، 4 و 2 بوده است. در مقایسۀ رگبارهای مختلف نیز به‌ترتیب رگبارهای 4، 2، 1 و 3 بیشترین تأثیر را روی ناپایداری مقاطع نشان داده‏اند. نتایج آنالیز حساسیت مدل نسبت به پارامترهای ورودی نشان داد که فاکتور ایمنی بیشترین میزان حساسیت را نسبت به ارتفاع جریان، تراز آب و چسبندگی بین ذرات به‌ترتیب با ضریب تغییرات 55، 17 و 10 درصد داشته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The investigation of Bank Stability and Toe Erosion Because of Surface Flow Using BSTEM Model (Case Study: Beshar River)

نویسندگان [English]

  • Majid Khazaei 1
  • Ahmad Nohegar 2
  • Rasool Mahdavi Najafabadi 3
  • Abdolrasool Telvari 4
1 Ph.D Student, Watershed Management Engineering, Hormozgan University
2 Faculty of Environment, University of Tehran
3 Department of Rangeland & Watershed Management, Hormozgan University
4 Science and Research Branch, Islamic Azad University, Ahwaz
چکیده [English]

The Vital need for river management is understood and predict of bank erosion processes. Almost models will not be able to evaluate bank erosion,accurately. BSTEM model is the most usable model in many of river engineering projects in the world. Necessary data for this model are related to driving and resisting forces controlled by hydraulic and Geotechnical processes. These data include geometry, hydraulic and Geotechnical data that using of sampling, field measurements and laboratory test obtained. The results of this study showed that the regions with cover vegetation in comparison to theregion of cover vegetation without significant differences in sustainability observed. Safety factor in the regions without cover vegetation is less than 1 that river in this section is instable Among the region of without cover vegetation only section 3 (event 4) have shown a safety factor less than 1. Compare the sections of viewpoint safety factors have shown that sections 5, 6, 8, 7, 3, 1, 4, 2 were unstable, respectively. Compare the sections showed that the events of 4, 2, 1 and 3 have the most impact on sections usability, respectively.Results of the sensitivity analysis model to input parameters indicated that safety factor has the most sensitive to height, water level and cohesion between particles with a variation coefficient 55%, 17% and 10%, respectively.

کلیدواژه‌ها [English]

  • Bank erosion
  • Beshar River
  • instability
  • Model
  • Safety factor
  • Toe Erosion
 
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