بررسی جابجایی‌های قائم و افقی سد خاکی ایوشان با استفاده از ابزاردقیق و تحلیل عددی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار، گروه مهندسی عمران، دانشگاه آیت الله العظمی بروجردی (ره)، بروجرد ، ایران.

2 دانش آموخته، آب و سازه‌های هیدرولیکی، دانشگاه آیت الله العظمی بروجردی (ره)،بروجرد ، ایران.

چکیده

به طورکلی ایمنی سد تنها به طراحی و ساخت آن مربوط نمی‏شود، بلکه به رفتارنگاری کاملی از عملکرد آن در اولین دوره آبگیری و بهره‏برداری و همچنین سرویس‏دهی منظم در طول عمر سد وابسته است. در این پژوهش جابجایی‌های قائم و افقی سد ایوشان با استفاده از نتایج ابزاردقیق در یک دوره زمانی هشت ساله در سه دوره ساخت، اولین آبگیری و بهره‌برداری تحلیل شده است. مدل عددی بزرگترین مقطع سد توسط نرم‌افزارهایGeostudio و Plaxis  تهیه و با لحاظ مدل رفتاری موهر کولمب بررسی گردید. با توجه به نتایج ابزاردقیق، نشست‎ در هسته سد روند افزایشی داشته و بعد از گذشت مدتی از پایان ساخت سد تقریباً به مقدار ثابتی می‌رسد. حداکثر نشست هسته سد در پایان مرحله ساخت به میزان 809 میلی‌متر و معادل 2/1 درصد ارتفاع سد در تراز میانی رخ داده است. جابجایی‌های افقی در جهت طولی بالادست سد کاملاً تحت تاثیر تراز آب مخزن و نیروهای هیدرواستاتیکی است. بیشینه جابجایی افقی در پوسته بالادست سد ایوشان 6/75 میلی‌متر می‌باشد. پس از آبگیری سد، مقدار نشست از ترازهای پایین به طرف ترازهای بالا (تاج سد) روند افزایشی داشته است. به منظور تطبیق داده‎های مشاهداتی و پیش‎بینی شده از رگرسیون چند متغیره و از معیار ضریب تعیین استفاده شد که نتایج  هم‌خوانی حدود 85 درصدی بین داده‎های مشاهداتی و پیش‎بینی شده را نشان می‎دهد و بیانگر اینست که مقادیر نشست حداکثر و محل وقوع آنها با مشخصات فنی موجود مطابقت خوبی دارد و نشان‌دهنده عملکرد مناسب سد ازلحاظ نشست می‌باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Study of Vertical and Horizontal Displacements of Eyvashan Earth Dam Using Instrumentation and Numerical Analysis

نویسندگان [English]

  • Mehdi Komasi 1
  • behrang beiranvand 2
1 Assistant Professor, Hydraulic Structure, Department of Civil Engineering, Faculty of Engineering, University of Ayatollah ozma Borujerdi, Borujerd, Iran
2 Assistant Professor, Hydraulic Structure, Department of Civil Engineering, Faculty of Engineering, University of Ayatollah ozma Borujerdi, Borujerd, Iran
چکیده [English]

Generally, the safety of a dam is not only related to its design and construction, but also to the complete characterization of its performance during the first dewatering and operation period, as well as regular service during the life of the dam. In this study, the vertical and horizontal displacements of the Eyvashan Dam were analyzed using actual instrument results in an eight-year period in three steps of construction, first dewatering and operation period. The numerical model of the largest section of the dam was prepared by Geostudio and Plaxis software and examined with respect to the behavioral model of Mohr–Coulomb. According to the results of the instrumentation, the settlement of the dam core has increasing trend and sometimes after the construction, it reaches almost constant. The maximum settlement of the dam core at the end of construction phase was 809 mm which is equal to 1.2% of the dam height at the middle level. The horizontal displacements in the longitudinal direction of dam upstream are completely influenced by the reservoir water level and hydrostatic forces. The maximum horizontal displacement in the upper crust of Eyvashan dam is 75.6 mm. After reservoir filling, the amount of settlement from the lower levels to the higher levels (crest of the dam) have had an increasing trend. In order to adapt the observational and predictive data, multivariate regression and determination coefficient were used which showed a consistency result of about 85 percent between observation and prediction data. This indicates that the maximum settlements and their location are agreed well with the technical specifications, revealing the proper operation of the dam in terms of settlement.

کلیدواژه‌ها [English]

  • Eyvashan earth dam
  • Geostudio
  • Instrumentation
  • Plaxis
  • settlement
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