مطالعه عددی تأثیر نسبت سختی رافت-خاک بر رفتار فونداسیون رافت شمعی واقع بر خاک ماسه ای

نوع مقاله : مقاله عمران

نویسندگان

گروه مهندسی عمران، دانشگاه آزاد اسلامی واحد مهاباد، مهاباد، ایران

چکیده

فونداسیون رافت شمعی (PRF) ترکیبی از شمع و رافت است که ظرفیت باربری کافی را در زیر نشست مجاز فراهم می کند. در این مقاله جهت بررسی رفتار سیستم فونداسیون رافت شمعی واقع بر خاک های ماسه ای تحت بار عمودی، از روش المان محدود و از نرم افزار PLAXIS 3D استفاده شده است. در برنامه المان محدود 27 مدل عددی برای رافت بدون شمع و مسلح به شمع شبیه سازی و آنالیز گردید. تأثیر سختی رافت- خاک، تعداد، فاصله و آرایش بندی شمع ها بر رفتار کلی بار- نشست، بهبود ظرفیت باربری، کاهش نشست و سهم تقسیم بار بین رافت و گروه شمع مورد بحث قرار گرفت. نتایج نشان داد که افزایش سختی رافت- خاک و تعداد شمع ها کمترین تأثیر را بر مکانیسم کلی منحنی بار- نشست دارد. افزایش سختی رافت- خاک ظرفیت باربری و نسبت کاهش نشست را به ترتیب به طور متوسط 19% و 23% بهبود بخشید و سهم بار حمل شده توسط رافت را حدود 5% کاهش داد. علاوه بر آن افزایش تعداد شمع ها ظرفیت باربری و نسبت کاهش نشست را به ترتیب در حدود 71% و 55% بهبود بخشید و سهم بار حمل شده توسط رافت را بطور فزآینده و به میزان 41% کاهش داد. همچنین آرایش بندی و فاصله شمع ها، تاثیر اندکی در حدود 4% بر رفتار کلی بار- نشست، سهم تقسیم بار بین رافت و شمع، بهبود ظرفیت باربری و کاهش نشست داشت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Study of the Influence of the Raft-Soil Stiffness Ratio on the Behavior of the Piled Raft Foundation Located on Sandy Soil

نویسندگان [English]

  • Masoud Yousefi
  • Loghman Rahimi
  • Hadi Azizian
Department of Civil Engineering, Mahabad Branch, Islamic Azad University, Mahabad, Iran
چکیده [English]

The Piled raft foundation (PRF) is a combination of pile and raft that provides adequate bearing capacity under the allowable settlement. In this article, finite element method and PLAXIS 3D software is used to investigate the behavior of piled raft foundation system located on sandy soils under vertical load. In the finite element program 27 numerical models simulated and analyzed for rafts without piles and reinforced with piles. The effect of raft-soil stiffness, number, spacing, and piles arrangement on the general load- displacement behavior, improvement of bearing capacity, reduction of settlement and the Share of load distribution between raft and piles group discussed. The results shown that increasing the soil- raft stiffness and the number of piles has the least effect on the general mechanism of the load-settlement curve. Increasing the raft-soil stiffness improved the bearing capacity and settlement reduction ratio by an average of 19% and 23%, respectively, and the share of load carried by the raft by about 5% reduced. In addition, increasing the number of piles improved the bearing capacity and settlement reduction ratio by about 71% and 55%, respectively, and the share of load carried by the raft by an increasing amount of 41% reduced. Also, the arrangement and spacing of piles had a small effect of about 4% on the general load-settlement behavior, the share of load sharing between rafts and piles, improving the bearing capacity and reducing settlement.

کلیدواژه‌ها [English]

  • Raft-Soil stiffness ratio
  • Pile group
  • Sandy soils
  • Bearing capacity
  • Settlement
  • 3D finite elements method
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