تاثیر فاصله نصب صفحات مغروق بر آبشستگی اطراف تکیه گاه پل

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد مهندسی آب و سازه های هیدرولیکی، گروه سازه های آبی، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز، اهواز.

2 استاد گروه سازه های آبی، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز

3 استادیار دانشکده مهندسی علوم آب دانشگاه شهید چمران اهواز

چکیده

شکستوتخریبپل­ها بر اثر آبشستگی در فونداسیون آنها علاوهبرخساراتمالیوبعضاًجانی، راهارتباطیبهنقاطسیلگیرومحتاجکمکرسانیرانیز قطعمی­کند. مطالعات انجام شده روی ۳۸۳ پل در ایالات متحده نشان می­دهد که در ۲۵ درصد آن­ها تخریب پایه و در ۷۲ درصد تخریب تکیه­گاه، علت شکست پل بوده است. به همین منظور حفاظت پایه و تکیه­گاه پل از اهمیت زیادی برخوردار بوده است. صفحات مغروق صفحاتی هستند که بر خلاف سایر روش­ها روی بستر قرار نمی­گیرند که خود باعث آبشستگی بستر شوند بلکه با فاصله از بستر و به صورت مغروق درون عمق آب قرار می­گیرند. هدف این تحقیق بررسی عملکرد صفحات مغروق در کنترل آبشستگی اطراف تکیه­گاه پل به ازای فواصل نصب مختلف (فواصل ۵/۰، ۱، ۵/۱ و ۲ برابر طول مؤثر تکیه­گاه) و تحت شرایط مختلف جریان (اعداد فرود ۱۵/۰، ۱۷/۰، ۲/۰ و ۲۲/۰) می­باشد. نتایج نشان داد که به­طور متوسط در شرایط مختلف جریان صفحات با فواصل نصب La۵/۰، La۱، La۵/۱ و La۲ عمق آبشستگی تکیه­گاه را به­ترتیب 23، ۱7، ۳۱ و ۴۲ درصد  نسبت به حالت بدون حضور صفحه کاهش دادند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The Effect of Installing Immerse Vanes on Scouring Around Bridge Abutments

نویسندگان [English]

  • Atefe Heydari 1
  • Mahmood Shafai Bajestan 2
  • Mohammad Bahrami Yarahmadi 3
1 MSC Student, Department of Water Structures, Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz.
2 Department of Water Structures, Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz
3 Assistant Professor, Department of Water Structures, Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz.
چکیده [English]

To control scour, it is first necessary to examine the scouring mechanism and the flow patterns around the abutment. By constructing of the abutment, the approaching flow pattern around it is disturbed. In addition, this brings about an increase in the average flow velocity due to narrowing, and the three-dimensional patterns of the flow are formed around the bridge abutment, which is the main cause of the local scour around the structure. To protect the bridge from scouring, two measures have been developed in the past; a) the direct methods and b) the indirect methods, which modify the flow pattern and reduce the power of vortex vortices. One can mention the use of roughness, sluts, submerged vanes and immerse vanes. One of the problems in using submerged vanes is the scouring formed around these structures because these vanes are placed on the bed and the three-dimensional patterns around them form and cause the scour around the vanes and eventually lead to their destruction. On the contrary, immerse vanes are located above the bed and their destruction from bed scouring is impossible. Application of immerse vanes was first studied by Shafai-Bejestan et al. (2016) in order to control the scouring of the outer river banks in a 180 degree flume bend. Their results showed that by installing the immerse vanes on the outer bank of the bend, the amount of scour depth decreases in the area of ​​the outer bank toe. On the other hand, the use of these vanes to control the scour of the bridge abutments has not been studied so far. Therefore, the present research has been carried out. In this study, the immerse vanes with four different distances, each with four different flow conditions, were tested to determine the most appropriate distance between the plates.

کلیدواژه‌ها [English]

  • Scouring
  • Immerse Vanes
  • Bridge Abutments

مراجع

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علوم و مهندسی آبیاری
دوره 42، شماره 2
تیر 1398
صفحه 215-230

فایل ها

سابقه مقاله

  • تاریخ دریافت: 11 اردیبهشت 1397
  • تاریخ بازنگری: 27 شهریور 1397
  • تاریخ پذیرش: 01 مهر 1397
  • تاریخ انتشار: 01 تیر 1398

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