مطالعه آزمایشگاهی تأثیر همزمان شکل و زاویه طولی دماغه پایه‌ پل بر آب‌شستگی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه عمران، واحد شوشتر، دانشگاه آزاد اسلامی، شوشتر، ایران

2 گروه مهندسی آب، مرکز تحقیقات علوم آب و محیط زیست، واحد شوشتر، دانشگاه آزاد اسلامی، شوشتر، ایران

3 استادیار مرکز تحقیقات علوم آب و محیط زیست، واحد شوشتر، دانشگاه آزاد، شوشتر، ایران

چکیده

تجربه طولانی ‌مدت احداث پل بر روی رودخانه‌ها و تخریب آنها و بررسی علل تخریب مهندسان را به این نتیجه رسانده است که در طراحی پل‌ها باید مسایل مربوط به ابشستگی اطراف پایه را بسیار مورد توجه قرارداد. در تحقیق حاضر اثر توسعه طولی پایه، اثر زاویه عمودی ورودی پایه، اثر ضخامت پایه و شکل دماغه پایه برای رسوب با قطر متوسط 2/1 میلی‌متر مورد بررسی قرار گرفت. آزمایش بر روی پایه‌هایی با زوایای (45،60،75 و 90) انجام شد. نتایج نشان داد که زاویه دماغه تأثیر زیادی بر ماکزیمم عمق ایجاد شده دارد. هر چه زاویه دماغه کمتر در نظر گرفته شد، عمق آبشستگی و ابعاد چاله نیز کاهش یافت و در نهایت مشاهده گردید که در  زاویه 45 درجه بدون دماغه تا 51% برای پایه با ضخامت 30 میلی‌متر و 79% برای پایه 15 میلی‌متری و 89% با دماغه مثلثی با ضخامت 30 میلیمتر کاهش عمق آبشستگی نسبت به شاهد داشته است. از بین دماغه-های مثلثی و دایره‌ای، دماغه مثلثی در تمامی شرایط مورد بررسی، دارای عملکرد بهتری در محافظت پایه به میزان 4/96 درصد عمق آب‌شستگی بوده است. همچنین با کاهش ضخامت پایه، مقاومت در برابر جریان و بالطبع آن خلع و کاهش فشار در پشت پایه کاسته شده و در نتیجه آب‌شستگی به میزان 3/8 درصد در شرایط مشابه کاهش  نشان داده است. کلیه مراحل آزمایشگاهی این تحقیق در آزمایشگاه هیدرولیک دانشگاه صنعتی خاتم الانبیا بهبهان در سال 1399 انجام گردید.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental Study of the Simultaneous Effect of the Shape and Longitudinal Angle of the Bridge Pier on Scour

نویسندگان [English]

  • Peiman Eskafi 1
  • mohammad Mahmoudian Shoushtari 2
  • Mohsen Solimani Babarsad 3
  • Mohammadhossein Pourmohammadi 2
  • Behrouz Dahanzadeh 2
1 Department of Water Sciences, Water Science and Environmental Research Center, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran
2 Department of Water Sciences, Water Science and Environmental Research Center, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran
3 Water and Environmental Science Research Center, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran.
چکیده [English]

Engineers in recent decades have come to the conclusion that the design of bridges should be based not only on structural considerations but also on the impact of flow on bridges due to the long-term experience of building bridges over rivers. In this study, we investigated the effects of the longitudinal development of the pier, the vertical angle of the pier, the pier thickness, and the shape of the base nose for sediment with an average diameter of 1.2 mm. Experiments were performed on piers with angles (45, 60, 75 and 95). The results showed that the angle was different from different points along with the distance between the hole and the pier, and the scour depth was above the maximum depth created. At an angle of 45 degrees without a nose, the scour depth was reduced by 51% for the base with a thickness of 30 mm, 79% for the pier with a thickness of 15 mm, and 89% for the triangular nose with a thickness of 30 mm. Among the triangular and long noses, the triangular nose in all the studied conditions was better reduced by 96.4% scours depth. In addition, as the thickness of the pier decreased, the pressure applied to the pier decreased and, as a result, scouring decreased by 8.3%.

کلیدواژه‌ها [English]

  • Scour
  • Bridge pier
  • Scouring Depth
  • Clear Water
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