ارزیابی رفتار سیستم شالوده‌های همجوار متکی بر ماسه‌های مقید شده با مسلح کننده ژئوسل: مطالعه آزمایشگاهی

نوع مقاله : مقاله پژوهشی

نویسنده

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

چکیده

     تجربیات گذشته نشان می‌دهد که استفاده از مسلح کننده‌های سلولی در ماسه‌های ضعیف تاثیر قابل ملاحظه‌ای در فشار باربری و نشست شالوده‌های واقع بر این نوع بسترها دارد. با افزایش شدت بارها و ارتفاع سازه‌های در نزدیکی یکدیگر، ابعاد شالوده‌ها افزایش یافته و فاصله میان آن‌ها نزدیک‌تر می‌شود. قرار گرفتن شالوده‌ها در مجاورت یکدیگر سبب ایجاد اثر متقابل آن‌ها بر یکدیگر و در نتیجه تغییر مکانیسم گسیختگی، قابلیت باربری و نشست‌پذیری آن‌ها می‌گردد. رفتار شالوده‌های همسایه واقع بر خاک‌های ماسه‌ای مسلح شده با مسلح کننده‌های دو بعدی در ادبیات تخصصی همواره مطالعه شده است ولی این شرایط برای مسلح کننده‌های سلولی کمتر مورد توجه بوده است. از این جهت، در این مطالعه تاثیر همجواری دو شالوده‌ دایروی متقارن واقع بر ماسه نیمه متراکم تسلیح شده با ژئوسل مورد ارزیابی قرار گرفته است. با حفظ هندسه و موقعیت بهینه ثابت برای ژئوسل در خاک بستر، اثر تغییر فاصله بین شالوده‌ها بر میزان باربری و نشست آن‌ها مطالعه شده است. نتایج حاکی از آن است که وجود مسلح کننده سه بعدی در ترکیب با اثر همجواری شالوده‌ها می‌تواند باربری را بیش از 300% و نشست را تا بیش از 60% نسبت به یک شالوده منفرد مشابه واقع بر بستر غیرمسلح بهبود دهد. حداکثر باربری در حالتی به دست آمد که دو شالوده کاملا در مجاورت یکدیگر واقع شده باشند. زمانی که فاصله بین شالوده‌ها از سه برابر قطر شالوده بیشتر می‌شود اثر همجواری کاهش قابل توجهی داشته و هر کدام از شالوده‌ها تقریبا رفتاری مشابه یک شالوده منفرد را خواهند داشت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Assessment Behavior of Cojointed Footings System Placed on Sands Encased by Geocell Reinforcement: Experimental Study

نویسنده [English]

  • Pezhman Fazeli Dehkordi
Department of Civil Engineering, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
چکیده [English]

Previous experiences indicate that employing cellular reinforcements (such as geocell) in the weak sands beneath footings has significant influence on the bearing pressure and their settlement. The increased structures’ height and loads intensity lead to enhancement in the dimension of the footings and their spacing, thereby causing them to get closer to each other. Existing footings near each other create interaction problem that tends to change failure mechanism, the ability of load-carrying capacity and deformability. The behavior of nearby footings resting on sandy soils reinforced with 2D polymeric reinforcements has been elucidated in the literature; however, it has not been attended for cellular reinforcements. By keeping optimum geometry and location for cellular reinforcement embedded in the soil, the effect of spacing between footings on bearing capacity and settlement was studied. The results show that coupled effect of reinforcement and footing interference can enhance load carrying capacity by more than 300% and improve the settlement by more than 60% compared with single isolated footing on an unreinforced bed. Maximum bearing capacity is attained when two footings are beside. Spacing between footings more than three times of footing diameter represents substantial reduction in the interference effect and each footing almost acts as a single isolated footing.

کلیدواژه‌ها [English]

  • Weak sands
  • Footings interference effect
  • Cellular reinforcement
  • Bearing capacity and settlement
  • Failure mechanism
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