ارزیابی رفتار شالوده‌ دایره‌ای مستقر بر بستر ماسه‌ای مسلح شده با ژئوسل

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه عمران، دانشگاه آزاد اسلامی واحد شهرکرد، شهرکرد، ایران.

2 دانشکده عمران، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران.

3 دانشکده عمران، معماری و هنر، دانشگاه آزاد اسلامی واحد علوم و تحقیقات، تهران، ایران.

چکیده

وجود بستر صلب نظیر سنگ سخت در زیر لایه‌های ماسه‌ای نسبتاً نازک و استفاده از مسلح‌کننده‌های سه بعدی (ژئوسل) می‌تواند سبب بهبود قابل توجه رفتار و ظرفیت باربری شالوده‌های سطحی گردد. در این مطالعه رفتار شالوده‌های دایره‌ای واقع بر خاک‌های ماسه‌ای نازک در حالت غیرمسلح و مسلح شده با ژئوسل مورد مطالعه قرار گرفته است. با انجام آزمون‌های بزرگ مقیاس، تأثیر ابعاد شالوده، ضخامت لایه ماسه‌ای و ژئوسل به صورت همزمان و مجزا بر میزان باربری و رفتار پی دایره‌ای بررسی شد. اثر تغییر در ضخامت لایه خاکی بر رفتار شالوده با ثابت در نظر گرفتن ابعاد و موقعیت بهینه برای ژئوسل ارزیابی گردید. بر طبق نتایج، بهبود ظرفیت باربری و کاهش نشست شالوده در هر دو حالت مسلح و غیرمسلح در شرایط با نسبت ضخامت لایه ماسه‌ای به عرض شالوده کمتر از دو مشاهده گردیده است. همچنین عمق اثرگذاری بستر صلب در هر دو حالت، حدود دو برابر عرض شالوده بوده است. ترکیب مسلح‌کننده ژئوسل و بستر صلب به ترتیب به عنوان عامل‌های محصور کنندگی جانبی و قائم، ظرفیت باربری را تا 45% افزایش و نشست در نقطه گسیختگی را تا 53% کاهش داده است. نتایج این آزمون‌ها در تعریف ضرایب جدید برای بسط روابط کلاسیک ظرفیت باربری برای شالوده‌های واقع بر خاک‌های با ضخامت کم در حالت مسلح و غیرمسلح مورد استفاده قرار گرفته و مقایسه دستاوردهای حاصل از این پژوهش با تحقیقات پیشین، سازگاری خوب آن‌ها را تأیید نموده است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Evaluation Behavior of Circular Footings Located on Sand Bed Reinforced with Geocell

نویسندگان [English]

  • Pezhman Fazeli Dehkordi 1
  • Mahmoud Ghazavi 2
  • Navid Ganjian 3
1 Department of Civil Engineering, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
2 Department of Civil Engineering, K.N. Toosi University of Technology, Tehran, Iran
3 Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
چکیده [English]

The rigid base proximity (such as stiff rock) under a relatively thin sand stratum and employing a 3D reinforcement (e.g. geocell) can tend to significant improvement in the bearing capacity of shallow footings. In this study, the behavior of circular footings located on unreinforced and geocell-reinforced thin sand layers was investigated. The simultaneous or individual effects of footing dimensions, sand layer thickness, and geocell reinforcement on the bearing capacity and settlement of footing were studied by conducting large-scale model tests. The influence of soil layer thickness on footing behavior was elucidated by considering optimum dimensions and location for geocell reinforcement. Based on the results, improvement in the bearing capacity and settlement reduction for both unreinforced and reinforced footing beds were observed when the sand layer thickness is lower than two times the footing width. Additionally, the effective depth of the rigid base for both cases was obtained two times of footing width. The combination of geocell-reinforcement and rigid base as lateral and vertical confinement factors led to an increase in the bearing capacity and settlement reduction at the failure point up to 45% and 53%, respectively. The test’s results were served to define new factors extending classical bearing capacity equations for footings located on thin soil at reinforced and unreinforced cases. The comparison of results with the previous investigations confirmed their good agreement.

کلیدواژه‌ها [English]

  • Circular footing
  • Bearing capacity
  • Sand
  • Rigid base
  • Geocell

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نشریه مهندسی عمران امیرکبیر
دوره 53، شماره 5
مرداد 1400
صفحه 1801-1820

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