بررسی رفتار جانبی پی تقویت شده با ریزشمع تحت اثر توام بارگذاری قائم و افقی

نوع مقاله : مقاله پژوهشی

نویسندگان

• شادان عابدینی
• جعفر بلوری بزاز

گروه مهندسی عمران، دانشکده مهندسی، دانشگاه فردوسی مشهد، مشهد، ایران

10.22067/jfcei.2023.79201.1184

چکیده

ریزشمع‌ها یکی از اجزا پرکاربرد در مهندسی عمران به جهت تقویت پی‌ها و یا بهسازی خاک هستند. از این عناصر در پی توربین‌های بادی نیز بهره جسته می‌شود. پی این سازه‌های بلند علاوه بر نیروی قائم حاصل از وزن توربین، تحت اثر نیروی قابل توجه جانبی نیز قرار دارند. در این تحقیق نیز سعی شده است تا با مدل‌سازی پی تقویت شده با استفاده از ریزشمع به بررسی رفتار این پی مربعی با بعد 20 سانتی‌متر تحت بار جانبی پرداخته شود. بدین منظور پی تقویت شده با تعداد 2، 4 و 8 ریزشمع به طول‌های 40 و 60 سانتی‌متری در داخل خاک ماسه‌ای و به‌صورت آزمایشگاهی مدل‌سازی شده و تحت بار جانبی استاتیکی قرار گرفته است. نتایج آزمایش‌ها نشان داد که این تقویت در مواردی تا 6 برابر ظرفیت باربری را بهبود داده است. از طرفی با بررسی رفتار گروهی ریزشمع مشاهده شد هنگامی که بار وارد شده از بار گسیختگی فاصله داشته باشد، طول ریزشمع‌ها تأثیر چندانی بر نقش هر ریزشمع در تأمین مقاومت جانبی ندارد و در بیشترین حالت (8 ریزشمع سربار قائم 15%) این اختلاف 30 درصد بوده است. همچنین در این تحقیق مشخص شد افزایش تعداد ریزشمع در حالات مختلف، باعث ایجاد دو رفتار متفاوت می‌شود. افزایش تعداد ریزشمع در حالت نزدیک به گسیختگی باعث افزایش نقش ریزشمع‌ها و در حالت دور از گسیختگی باعث کاهش نقش شده است. مهم‌ترین پارامتر تأثیرگذار این حالات، تعداد ریزشمع بوده است که در بیشترین حالت باعث افزایش 200 درصدی نقش ریزشمع در رفتار گروهی آن گشته است.

کلیدواژه‌ها

• ظرفیت باربری جانبی
• پی سطحی
• ریزشمع
• بار قائم
• ماسه

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عنوان مقاله [English]

Investigation of lateral behavior micropiled foundation under combined lateral and vertical loading

نویسندگان [English]

• Shadan Abedini
• J. Bolouri Bazzaz

Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

چکیده [English]

Micropiles are one of the most widely used components in civil engineering to strengthen foundations or improve the soil. These elements are also used in wind turbines. In addition to the vertical force resulting from the weight of the turbine, these tall structures are also affected by significant lateral force. This paper aims to investigate the behavior of a square micropiled foundation with the dimension of 20 cm under lateral loading. For this purpose, the reinforced foundation with 2, 4, and 8 micropiles with lengths of 40 and 60 cm in the sandy soil has been modeled experimentally and subjected to static lateral load. Also, the effect of vertical surcharge load on lateral bearing capacity has been investigated in different conditions. The results of the tests revealed that this type of reinforcement has improved the bearing capacity up to 6 times in some cases. Studying micropile collective behavior unveiled that, distant from collapse, micropile length minimally affected individual lateral capacity. In the extreme scenario (8 micropiles, 15% overload), this discrepancy was 30%. Varying micropile numbers near collapse produced two contrasting behaviors: amplification in one and reduction in another case. The determining factor in both instances was the micropile quantity, leading to a remarkable 200% role increase in the most extreme conditions.

کلیدواژه‌ها [English]

• Lateral bearing capacity
• Shallow foundation
• Micropile
• Vertical load
• Sandy soil

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