مطالعه عددی میزان مقاومت روکش بتن بر رفتار سد سنگریزه ای

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشگاه ازاد اسلامی واحد لاهیجان،لاهیجان،ایران

2 دانشجوی دکتری گروه عمران دانشگاه قم ، قم ، ایران

3 گروه عمران دانشگاه آزاد اسلامی واحد لاهیجان ، لاهیجان ، ایران

چکیده

زلزله‌ها ‌از عمده‌ترین پدیده‌های تاثیر گذار بر روی سازه‌ها هستند و مهندسان معیارهای طراحی را در راستای مقابله با اثرات آن بکار می‌گیرند. به لحاظ درجه ایمنی خاص برای سدهای ‌، لازم است که طرح سدهای بزرگ، بزرگترین زلزله قابل باور را در تحلیل مخاطرات و بررسی احتمالات با صرفه نظر از میزان زمان بازگشت آن در طراحی وارد نماید‌. سد های سنگریزه ای عمدتا پوشش بتنی یا آسفالتی دارند که این پوشش علاوه بر نفوذناپذیری در مقابل آب، باعث افزایش پایداری سد می شود. از آنجاییکه تعدادی سد سنگریزه ای در ایران احداث شده و چندین سد سنگریزه ای دیگر نیز در دست احداث می باشند ، بررسی و تحلیل این نوع از سدها برای مطالعات حال و آینده مهندسی سد بسیار مهم و حائز اهمیت می باشند. در این پژوهش مدلسازی سد سنگریزه ای در نرم افزار آباکوس و همچنین صحت سنجی مدل انجام خواهد گردید. ابتدا مدل ارائه شده در مقاله مرجع مدلسازی و صحت سنجی می گردد.مدل مورد استفاده در صحت سنجی و این پژوهش سد مسوچورا در یونان می باشد. پس از اطمینان از صحت مدلسازی و تحلیل ، تاثیر مقاومت بتن روکش سد تحت اثر شتابنگاشت های انتخابی و با تغییر مقاومت بتن و همچنین تاثیر در نظر گرفتن میرایی بتن سنجیده شد و در نهایت نتایج مقایسه گردیدند. شتابنگاشت های مورد استفاده در این تحقیق نورثریج ،بم ، سن فرناندو و طبس می باشد. تغییرات در مقاومت بتن در سه نوع C20،C25 و C30 با مقاومت اسمی نمونه فشاری استوانه 20،25 و 30 مگاپاسکال انجام شد و این افزایش مقاومت حدود 8 تا 10 درصد در کاهش تغییر مکان جانبی تحت شتابنگاشت های انتخابی در تاج سد را در بر دارد. با لحاظ نمودن اثر میرایی در بتن با مقدار 0325/0 ، تحت شتابنگاشت های انتخابی تغییری در حدود 3 درصد در تغییر مکان جانبی تاج سد دارد در عین حال که در تخریب کششی رویه بتنی تاثیر ناچیزی دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Study of The Strength of Concrete Coating on The CFRD Dam

نویسندگان [English]

  • alireza mardookhpour 1
  • Ramtin Sobhkhiz 2
  • Seyed Ali Asgharifar 3
1 department of civil engineering,islamic azad university,lahijan branch,iran
2 PhD student of Civil Engineering Department, Engineering Faculty, University of Qom, Qom,iran
3 Civil Engineering Department, Lahjian Branch, Islamic Azad University ,Lahijan. Iran
چکیده [English]

Earthquakes are one of the major phenomena affecting structures and engineers use design criteria to deal with their effects. In terms of the specific degree of safety for dams ‌, it is necessary that the design of large dams include the largest believable earthquake in hazard analysis and probability consideration regardless of the amount of time it returns in the design. Pebble dams have mainly concrete or asphalt coating, which in addition to impermeability to water, increases the stability of the dam. Since a number of gravel dams have been constructed in Iran and several other gravel dams are under construction, the study and analysis of this type of dam is very important for current and future studies of dam engineering. In this research, pebble dam modeling will be done in Abacus software as well as model validation. First, the model presented in the reference article is modeled and validated. The model used in validation and this research is Musouchura Dam. After ensuring the accuracy of modeling and analysis, the effect of concrete strength of dam cover under the effect of selected accelerometers and by changing the strength of concrete and also the effect of considering the damping of concrete were measured and finally the results were compared. The accelerometers used in this study are Northridge, Bam, San Fernando and Tabas. Changes in concrete strength in three types C20, C25 and C30 with nominal strength of cylindrical compression specimens of 20, 25 and 30 MPa were made and this increase in strength is about 8 to 10% in reducing lateral displacement under selected accelerometers in the dam crown has it. Considering the damping effect in concrete with a value of 0.0325, under selected accelerometers, there is a change of about 3% in the lateral displacement of the dam crown, while it has little effect on the tensile degradation of the concrete surface.

کلیدواژه‌ها [English]

  • numerical simulation
  • CFRD Dam
  • earthquake
  • Concrete Coating

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