نوع مقاله : یادداشت فنی
نویسندگان
چکیده
مدل‌سازی جریان نشت از زیر سازه‌های آبی که بر روی پی با مواد نفوذپذیر ساخته شده‌اند، از جمله موارد اساسی است که قبل از احداث سازه باید بررسی شود، تا از مشکلاتی مانند فرسایش مواد پی، نشست سازه و نشت آب از زیر سازه جلوگیری شود. در صورتی که در فرآیند طراحی نتوان بر مواردی مانند پدیده لوله‌ای شدن، کاهش نیروهای زیرفشار و گرادیان هیدرولیکی و همچنین کنترل جریان نشت از زیر سازه فائق آمد، می‌توان از راه‌حل‌هایی کمکی مانند احداث کف‌بندهای افقی، دیواره‌های آب‌بند و همچنین نصب سوراخ‌آب استفاده کرد. در این پژوهش به بررسی تأثیر سوراخ‌آب روی توزیع زیرفشار و گرادیان هیدرولیکی پرداخته شده است. برای این منظور معادله حاکم بر جریان نشت از محیط متخلخل به کمک روش عددی حجم کنترل برای حالت‌های مختلف حل شد. تمامی محاسبات توسط محیط ساده ولی قدرتمند صفحه گسترده Excel انجام شده است. نتایج این پژوهش نشان می‌دهد استفاده از سوراخ‌آب در کف‌بند حوضچه آرامش سد می‌تواند از عمق دیواره‌های آب‌بند مورد نیاز بکاهد که این امر موجب صرفه‌جویی اقتصادی زیادی برای طرح می‌شود. هر‌چه سوراخ‌آب از پنجه سد فاصله پیدا کند و به پایین‌دست سازه منتقل شود از تأثیر مثبت آن کاسته می‌شود.
کلیدواژه‌ها
عنوان مقاله [English]
Weep hole effect on uplift pressure distribution and hydraulic gradient beneath concrete dams with permeable foundation
نویسندگان [English]
- Navid Nasehi Oskouie
- Farzin Salmasi
چکیده [English]
Seepage flow modeling beneath hydraulic structures on permeable materials is an essential issue that must be considered before construction processes. Because of no detailed studies, followed by inappropriate design some problems such as foundation erosion, seepage and water escape and structure settlement may be occurring. If we couldn’t overcome these problems in designing process, we can utilize a series of auxiliary actions. Some actions for eliminating the piping and reducing the uplift pressure and hydraulic gradient are construction of horizontal apron, cut-off walls and also weep holes. Hence, in this study the effect of the weep hole on uplift pressure and hydraulic gradient has been investigated. For this purpose, the governing equation of flow through porous media has been solved for different setups, by the numerical method of Control Volume. All calculations have been done by the simple and powerful Excel Spreadsheet tools. Results show that, the application of weep hole reduces the uplift pressure and hydraulic gradient. Installation of a weep hole on stilling basin could reduce the cut-off wall depth and this cause a noticeable reduction of project costs. By moving weep hole toward the downstream of stilling basin and getting away from dam toe, its positive impact will be reduced.
Seepage flow modeling beneath hydraulic structures on permeable materials is an essential issue that must be considered before construction processes. Because of no detailed studies, followed by inappropriate design some problems such as foundation erosion, seepage and water escape and structure settlement may be occurring. If we couldn’t overcome these problems in designing process, we can utilize a series of auxiliary actions. Some actions for eliminating the piping and reducing the uplift pressure and hydraulic gradient are construction of horizontal apron, cut-off walls and also weep holes. Hence, in this study the effect of the weep hole on uplift pressure and hydraulic gradient has been investigated. For this purpose, the governing equation of flow through porous media has been solved for different setups, by the numerical method of Control Volume. All calculations have been done by the simple and powerful Excel Spreadsheet tools. Results show that, the application of weep hole reduces the uplift pressure and hydraulic gradient. Installation of a weep hole on stilling basin could reduce the cut-off wall depth and this cause a noticeable reduction of project costs. By moving weep hole toward the downstream of stilling basin and getting away from dam toe, its positive impact will be reduced.
Seepage flow modeling beneath hydraulic structures on permeable materials is an essential issue that must be considered before construction processes. Because of no detailed studies, followed by inappropriate design some problems such as foundation erosion, seepage and water escape and structure settlement may be occurring. If we couldn’t overcome these problems in designing process, we can utilize a series of auxiliary actions. Some actions for eliminating the piping and reducing the uplift pressure and hydraulic gradient are construction of horizontal apron, cut-off walls and also weep holes. Hence, in this study the effect of the weep hole on uplift pressure and hydraulic gradient has been investigated. For this purpose, the governing equation of flow through porous media has been solved for different setups, by the numerical method of Control Volume. All calculations have been done by the simple and powerful Excel Spreadsheet tools. Results show that, the application of weep hole reduces the uplift pressure and hydraulic gradient. Installation of a weep hole on stilling basin could reduce the cut-off wall depth and this cause a noticeable reduction of project costs. By moving weep hole toward the downstream of stilling basin and getting away from dam toe, its positive impact will be reduced.
Seepage flow modeling beneath hydraulic structures on permeable materials is an essential issue that must be considered before construction processes. Because of no detailed studies, followed by inappropriate design some problems such as foundation erosion, seepage and water escape and structure settlement may be occurring. If we couldn’t overcome these problems in designing process, we can utilize a series of auxiliary actions. Some actions for eliminating the piping and reducing the uplift pressure and hydraulic gradient are construction of horizontal apron, cut-off walls and also weep holes. Hence, in this study the effect of the weep hole on uplift pressure and hydraulic gradient has been investigated. For this purpose, the governing equation of flow through porous media has been solved for different setups, by the numerical method of Control Volume. All calculations have been done by the simple and powerful Excel Spreadsheet tools. Results show that, the application of weep hole reduces the uplift pressure and hydraulic gradient. Installation of a weep hole on stilling basin could reduce the cut-off wall depth and this cause a noticeable reduction of project costs. By moving weep hole toward the downstream of stilling basin and getting away from dam toe, its positive impact will be reduced.
کلیدواژه‌ها [English]
- Weep hole
- Uplift pressure
- Concrete dam
- Control volume
- Hydraulic gradient
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