رفتار استاتیکی پی رینگی بر بستر ماسه‌ای مسلح شده با ترکیب خرده لاستیک و ژئوگرید

نوع مقاله : مقاله پژوهشی

نویسندگان

گروه مهندسی عمران، دانشکده فنی مهندسی، دانشگاه هرمزگان، بندر عباس، ایران

چکیده

از پی‌های رینگی در صنایع مختلف از جمله نفت وگاز، استفاده می‌شود. بنابراین، این گونه از پی‌ها از اهمیت بالایی برخوردار بوده و اقداماتی برای بهبود رفتار آن، می‌تواند بسیار حائز اهمیت باشد. در پژوهش حاضر با استفاده از آزمایش‌های تجربی، رفتار پی رینگی با قطر خارجی ثابت 300 میلیمتر و مستقر بر بستر ماسه‌ای مسلح شده با خرده لاستیک دانه‌ای به تنهایی و همچنین در ترکیب با ژئوگرید، تحت بار استاتیکی، ارزیابی شده است. نتایج نشان می‌دهد در هر دو حالت بستر غیر مسلح و همچنین مسلح شده با خرده لاستیک، پی رینگی با نسبت قطر داخلی به خارجی برابر با 0/4 ،دارای بیشترین ظرفیت باربری می‌باشد. همچنین ضخامت بهینه لایه مخلوط خاک – خرده لاستیک برابر با نصف قطر خارجی پی رینگی می‌باشد، که در صورت استفاده از آن، ظرفیت باربری تا 41/5 درصد نسبت به حالت غیر مسلح افزایش می‌یابد؛ افزایش بیشتر این ضخامت نتیجه معکوس داشته و ظرفیت باربری را کاهش و نشست را افزایش می‌دهد. البته استفاده از مسلح کننده ژئوگرید در ترکیب با لایه مخلوط خاک - خرده لاستیک، می‌تواند قدری خاصیت تسلیح کنندگی این لایه با ضخامت‌های زیاد را فعال کند، ولی مقدار آن به قدری نیست که بتواند بر اثرات منفی ناشی از به کارگیری این لایه با ضخامت‌هایی بیش از ضخامت بهینه مذکور، غلبه کند. به طور کلی استفاده ترکیبی از مسلح کننده‌های ژئوگرید و خرده لاستیک تاثیر بیشتری نسبت به استفاده جداگانه از آن‌ها، داشته و می‌تواند ظرفیت باربری را تا 62/7 %نسبت به حالت غیر مسلح افزایش دهد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Static behavior of ring footing based on geogrid-rubber reinforced sand bed

نویسندگان [English]

  • Mohammad Hossein Keyghobadi
  • ADEL ASAKEREH
  • Behzad Kalantari
  • Masoud Dehghani
Department of civil engineering, Faculty of Engineering, University of Hormozgan, Bandar Abbas, Iran.
چکیده [English]

Ring footings have been used in various industries, like oil and gas. So this kind of footings is very important and doing some works to improve their behavior can be very important. In the present study, the behavior of ring footings with a constant outer diameter of 300 mm based on reinforced bed with granular rubber particles alone and also in combination with a geogrid layer, subjected to static loads, has been investigated by experimental tests. The results showed in both unreinforced and rubber-reinforced bed, the ring footing with inner to outer diameter ratio of 0.4 had the maximum bearing capacity. Also, the optimum thickness of rubber-reinforced layer is equal to 0.5 times the outer diameter of ring footing; in this case, the bearing capacity can be increased by 41.5% compared with the unreinforced bed; more increases than optimum value, have reverse results and lead to decrease in bearing capacity and increase in settlement. Using the geogrid layer can activate reinforcing effects of rubber-reinforced layer with high thicknesses, but its value is not big enough to overcome the negative effects of using rubber-reinforced layers with higher thicknesses than optimum value. At last, using geogrid reinforcement in combination with rubber particles can be more effective than using each of them alone. In geogrid-rubber reinforced bed, the bearing capacity can be increased by 62.7% compared with the unreinforced bed.

کلیدواژه‌ها [English]

  • Ring footing
  • rubber particle
  • Geogrid
  • Bearing Capacity
  • Settlement
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