پديد آورندگان :
اژدري، خليل داﻧﺸﮕﺎه ﺻﻨﻌﺘﯽ ﺷﺎﻫﺮود - ﮔﺮوه آب و ﺧﺎك , امامقلي زاده، صمد داﻧﺸﮕﺎه ﺻﻨﻌﺘﯽ ﺷﺎﻫﺮود - ﮔﺮوه آب و ﺧﺎك , رضايي، حوريه داﻧﺸﮕﺎه ﺻﻨﻌﺘﯽ ﺷﺎﻫﺮود - ﮔﺮوه آب و ﺧﺎك
كليدواژه :
آﺑﺸﮑﻦ ﻧﺎﻣﺘﻘﺎرن , آﺑﺸﺴﺘﮕﯽ , ﺗﮑﯿﻪ ﮔﺎه , ﭘﻞ , ﻣﻘﻄﻊ ﻣﺮﮐﺐ
چكيده فارسي :
ﺳﺎﺑﻘﻪ و ﻫﺪف: ﻃﺮاﺣﯽ و اﺳﺘﻔﺎده ﺻﺤﯿﺢ ﺳﺎزه هاي آبشكن ، ﻓﺮآﯾﻨﺪ آﺑﺸﺴﺘﮕﯽ را ﮐﻨﺘﺮل ﻧﻤﻮده و در ﺟﻬﺖ ﭘﺎﯾﺪاري ﭘﻞ ها ﻋﻤﻞ ﺧﻮاﻫﺪ ﮐﺮد. اﺛﺮات اﻧﻮاع آﺑﺸﮑﻦﻫﺎ ﺑﺮ اﻟﮕﻮي ﺟﺮﯾﺎن و ﺣﻤﻞ رﺳﻮب ﺑﻪ ﻃﻮر ﻗﺎﺑﻞ ﻣﻼﺣﻈﻪاي ﻣﺘﻔﺎوت ﺑﻮده و ﺑﻪ ﭘﺎراﻣﺘﺮﻫﺎي ﻃﺮاﺣﯽ آﺑﺸﮑﻦ، آراﯾﺶ آﺑﺸﮑﻦ، ﻫﯿﺪروﻟﯿﮏ ﺟﺮﯾﺎن، ﻧﻮع رﺳﻮب و اﻧﺪازه رﺳﻮب ﺑﺴﺘﮕﯽ دارد. در ﭘﺪﯾﺪه آبشستگي ﻋﻮاﻣﻞ ﻣﺨﺘﻠﻔﯽ ﺗﺄﺛﯿﺮﮔﺬار ﻫﺴﺘﻨﺪ ﮐﻪ ﺑﺮاي ﺑﺮرﺳﯽ اﺛﺮ آن ﻫﺎ ﻧﯿﺎز ﺑﻪ ﭘﮋوﻫﺶﻫﺎي ﻣﺘﻌﺪدي اﺳﺖ. ﻫﺪف از اﯾﻦ پژوهش ﻣﻄﺎﻟﻌﻪ ﭘﺎراﻣﺘﺮﻫﺎي ﺗﺄﺛﯿﺮﮔﺬار آﺑﺸﮑﻦ T ﺷﮑﻞ ﻧﺎﻣﺘﻘﺎرن ﺑﺮ ﺣﺪاﮐﺜﺮ ﻋﻤﻖ آﺑﺸﺴﺘﮕﯽ در ﻣﺤﻞ تكيه ﮔﺎه ﭘﻞ در ﻣﻘﻄﻊ ﻣﺮﮐﺐ ﻣﯽ ﺑﺎﺷﺪ.
ﻣﻮاد و روش ها : پژوهش حاضر بر روي فلوم مستطيلي شكل به عرض1متر، طول 12متر و ارتفاع 60 سانتي متر در آزمايشگاه تحقيقاتي ﻫﯿﺪروﻟﯿﮑﯽ داﻧﺸﮑﺪه ﮐﺸﺎورزي داﻧﺸﮕﺎه ﺻﻨﻌﺘﯽ ﺷﺎﻫﺮود صورت گرفت . آبشكن شكل نامتقارن ﺑﺎ ﭼﻬﺎر ﻧﺴﺒﺖ ﺑﺎل ﺑﺎﻻدﺳﺖ ﺑﻪ ﺑﺎل ﭘﺎﯾﯿﻦ دست ( 2/0، 5/0، 2 و 5) در فاصله هاي 9 ، 18، 27، 36، 45 سانتي متر از تكيه گاه نصب شدند . ميزان آبشستگي ايجاد شده در دماغه تكيه گاه تحت اثر دبي هاي 18، 20، 22، 24 ، 26 ليتر برثانيه مورد مطالعه قرار گرفت.
ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﺣﺎﺻﻠﻪ ﻧﺸﺎن داد ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻃﻮل ﺑﺎﻻدﺳﺖ ﻧﺴﺒﺖ ﺑﻪ ﭘﺎﯾﯿﻦ دﺳﺖ (اﻓﺰاﯾﺶ ﻧﺴﺒﺖ ﺗﻘﺎرن)، ﺣﺪاﮐﺜﺮ ﻋﻤﻖ آﺑﺸﺴﺘﮕﯽ ﮐﺎﻫﺶ و ﺑﺎ اﻓﺰاﯾﺶ ﻓﺎﺻﻠﻪ آﺑﺸﮑﻦ از ﺗﮑﯿﻪ ﮔﺎه ﻋﻤﻖ آﺑﺸﺴﺘﮕﯽ ﮐﺎﻫﺶ ﻣﯽ ﯾﺎﺑﺪ. ﻣﯿﺰان ﮐﺎﻫﺶ ﻋﻤﻖ آﺑﺸﺴﺘﮕﯽ ﺑﺎ دبي جريان 18 ليتر بر ثانيه 100درصد و براي دبي 26 ليتر بر ثانيه 70 درصد برآورده گرديد. با آناليز ابعادي انجام شده بر روي ﭘﺎراﻣﺘﺮﻫﺎي ﻫﯿﺪروﻟﯿﮑﯽ ﻣﺆﺛﺮ ﺑﺮ ﭘﺪﯾﺪه آﺑﺸﺴﺘﮕﯽ، راﺑﻄﻪاي ﺑﯽﺑﻌﺪ ﺑﻪ دﺳﺖ آﻣﺪ و در ﻧﻬﺎﯾﺖ ﺑﺎ اﺳﺘﻔﺎده از داده ﻫﺎي آزﻣﺎﯾﺸﮕﺎﻫﯽ، ﻣﻌﺎدﻟﻪ ﺟﺪﯾﺪي ﺑﺮاي ﺗﻌﯿﯿﻦ ﺣﺪاﮐﺜﺮ ﻋﻤﻖ آﺑﺸﺴﺘﮕﯽ اﻃﺮاف ﺗﮑﯿﻪﮔﺎه اراﺋﻪ ﺷﺪ.
ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﻧﺘﯿﺠﻪ ﻧﻬﺎﯾﯽ ﺣﺎﺻﻞ از اﯾﻦ ﭘﮋوﻫﺶ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻓﺎﺻﻠﻪ آﺑﺸﮑﻦ از ﺗﮑﯿﻪ ﮔﺎه، ﻣﯿﺰان ﺗﺄﺛﯿﺮﮔﺬاري آﺑﺸﮑﻦ ﺑﺮ ﮐﻨﺘﺮل آﺑﺸﺴﺘﮕﯽ ﺗﮑﯿﻪ ﮔﺎه اﻓﺰاﯾﺶ ﻣﯽ ﯾﺎﺑﺪ و در ﻧﺘﯿﺠﻪ ﻋﻤﻖ آﺑﺸﺴﺘﮕﯽ در دﻣﺎﻏﻪ ﺗﮑﯿﻪ ﮔﺎه ﮐﺎﻫﺶ ﭘﯿﺪا ﻣﯽ ﮐﻨﺪ.
چكيده لاتين :
Background and Objectives: Proper designing and using of spur dike structure can control scour and it can improve the stability of bridge. The effects of different types of spur dikes on the flow properties and sediment transport are different and they depend on the scour designing parameters, layout of spur dike, flow hydraulic, kind and size of sediment. Different factors have affected on the scour phenomena. For study of these factors different researches are necessary. The aim of this research is the study of effective parameters of asymmetric T-shaped spur dike on the maximum scour depth in bridges abutment in a compound sections.
Materials and Methods: This research has conducted on a rectangular shaped flume with dimensions of 1 m width, 12 m length and 60 cm depth in hydraulic laboratory of Agriculture collage, Shahrood University of Technology. Asymmetric T-shaped spur dike with 4 relative of upstream wing wall length to downstream wing wall length (0.2, 0.5, 2 and 5) installed at distances of 9, 18, 27, 36 and 45 cm from the abutment. The amount of scour in the front of abutment with discharges 18, 20, 22, 24 and 26 lit/s was studied.
Results: Result of this study reveal that the maximum scour depth is decreased with increasing of the ratio of the upstream wing-wall length of spur dike to the downstream wing-wall length and also results show that the scour depth is decreased when the distance of spur dike from the abutment is increased. Decreasing of the scour depth was 100% and 70% for discharge of 18 lit/s and 26 lit/s, respectively. With dimensional analysis of the hydraulic parameters such as discharge, average flow velocity, depth of water and geometric parameters of spur dike such as length of spur dike, length of wing-wall and distance of spur dike from the abutment, a dimensionless equation was achieved and finally based on the experimental data a new equation presented to estimate the maximum depth of scour around the abutment.
Conclusion: The main results of this research revealed that with increasing of the distance of spur dike from the abutment, the effect of spur dike on the scour around of abutment increased and as results the scour depth in the front of abutment will decrease.
