مطالعه آزمایشگاهی تأثیر پرده آب بند بر کنترل نشت و پدیده جوشش در پی سازه های هیدرولیکی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد ژئوتکنیک، دانشکده مهندسی، دانشگاه یاسوج

2 استادیار گروه مهندسی عمران، دانشکده مهندسی، دانشگاه یاسوج

3 استادیار گروه علوم خاک، دانشکده کشاورزی، دانشگاه یاسوج

چکیده

دیوارهای سپری از جمله تمهیداتی هستند که به منظور کاهش نشت، نیروی زیر فشار و شیب خروجی در پی نفوذپذیر سازه های آبی مورد استفاده قرار می گیرند. تاکنون تحقیقات زیادی در ارتباط با نشت از پی سازه های آبی، به ویژه در قالب مدل های عددی انجام شده است که برای ارزیابی درستی آنها به داده های صحرایی و آزمایشگاهی نیاز است. امّا تا به امروز یک مدل آزمایشگاهی یا فیزیکی که مسائل نشت و جوشش از پی سازه های هیدرولیکی را به طور دقیق مورد مطالعه قرار دهد، ارائه نشده است. در این تحقیق برای بررسی اثر عوامل مؤثر بر پدیده جوشش از پی سازه های هیدرولیکی مستقر بر پی های آبرفتی یک مدل آزمایشگاهی به طول 2/ 2، ارتفاع 8/ 0 و عرض 4/ 0 متر با استفاده از اسکلت فولادی و جداره های پلکس یگلاس ساخته و آماده گردید. در این مدل آزمایشگاهی پرده آب بند به عنوان متغیر عمقی، از ورقه پلکسی گلاس ساخته شده و ترازهای پیزومتریک در دو وجه پایین دست و بالادست فلوم با استفاده از پیزومترهای شفاف با قطر کم اندازه گیری شده اند. تأثیر موقعیت، عمق دیواره سپری بر مقدار دبی نشت و گرادیان خروجی در قالب نمودارهای بی بعد نشان داده شده است. این نتایج نشان می دهد که در نسبت عمق پرده آب بند 46 / d/D=0 با نسبت بیشترین تراز آب بالادست h/hm=1 پدیده جوشش رخ نمی دهد. مقدار دبی نشت و گرادیان هیدرولیکی در محدوده مساعدی قرار دارند.

کلیدواژه‌ها

عنوان مقاله [English]

Laboratory Investigation the Effects of sheet pile on Seepage Control and sand ‎boiling through Alluvial Foundation of hydraulic structures

نویسندگان [English]

  • M. Yousefi 1
  • M. Parvizi 2
  • M. Sedghi–Asl 3
1 M.Sc. Student of Civil Engineering, Faculty of Engineering, Yasouj University
2 Assistant Professor of Civil Engineering, Faculty of Engineering, Yasouj University
3 Assistant Professor of Soil Science, Agricultural College, Yasouj University
چکیده [English]

The sheet piles are used below hydraulic structures to reduce seepage flow rate and hydraulic gradient
at the outlet of such structures rested on permeable foundations. So far, for analysis of seepage flow
under hydraulic structures much research work has been carried out in the form of numerical and
analytical models. Nevertheless, less field and experimental works have been done to investigate boiling
phenomena for evaluating of the numerical models. In the present research, a laboratory apparatus was
built to simulate seepage and its controlling measures under sheet piles. The model consist of a flume
2.2 m long, 0.8 m deep and 0.4 m wide, in which vertical sheet pile were provided by Perspex sheets.
The flume was made of steel frame and Perspex as well as thick glass sheets. The foundation material
was made of clean, fine sand, compacted to a uniform density and covered the bottom 40 cm of flume.
Perspex sheets were employed sheet pile variable depth. The piezometric heads at both downstream
and upstream side of sheet pile were measured using small diameter clear plastic tubes. The effect of
position and depth of the sheet pile on the seepage flow and exit gradient have been demonstrated in
form of dimensionless curves. The results show that the depth of the sheet piles d/D=0.46 with the
maximum upstream water level h/hm=1.0 boiling phenomenon does not occur and the seepage rate and
hydraulic gradient in the area are favorable.

کلیدواژه‌ها [English]

  • Sand Boiling Phenomena
  • Seepage
  • Sheet Pile
  • Laboratory Model
  • Exit Gradiant

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 48، شماره 3
آبان 1395
صفحه 315-328

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