مدلسازی فیزیکی بررسی تاثیر پیکربندی مهار مارپیچ و سربار بر جابجایی دیوار

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار،گروه مهندسی عمران، واحد شهر قدس، دانشگاه آزاد اسلامی، تهران، ایران.

2 پردیس بین‌الملل دانشگاه خوارزمی، تهران، ایران،

3 استادیار، فنی و مهندسی، آزاد، کرج، ایران،

چکیده

مهارهای مارپیچ با ویژگی‌های منحصر به‌فرد خود کاربردهای فراوانی در ساخت و ترمیم پی‌ها و بهسازی خاک‌ها پیدا کرده است. با اینحال تحقیقات محدودی بر روی استفاده از این مهارها در پایدارسازی دیوار و شیب‌ها و ساخت دیوارهای حائل انجام شده است. برای این منظور مطالعه‌ای آزمایشگاهی در رابطه با پایدارسازی دیوار با سه نوع مهار مارپیچ و دو نوع شیروانی در خاک ماسه‌ا‌ی طراحی و انجام شد. هدف از آزمایش‌های انجام شده بررسی تأثیر شکل مهار و شیب پشت بالای دیوار بر جابجایی تاج دیوار بوده است. برای افزایش دقت اندازه‌گیری‎ها و تعیین کرنش‌های برشی از مقایسه تصاویر و روش سرعت‌سنجی تصویری ذرات(PIV )استفاده شده است. در نهایت برای بررسی پتانسیل اجرایی آن، به مقایسه نتایج بدست آمده با روش میخ‌کوبی متداول پرداخته شده است. با استفاده از مدل‌سازی‌های انجام شده مشخص شده است که میزان جابجایی تاج دیوار با افزایش قطر و تعداد صفحه‌های مارپیچ کاهش می یابد. این کاهش برای افزایش شعاع مارپیچ حدود30 درصد و برای افزایش تعداد صفحه و قطر در حدود 60 درصد بوده است. در صورت نیاز به کاهش چشم‌گیر جابجایی پیشنهاد می‌شود تعداد صفحه مهار افزایش یابد و قطر آن دچار تغییر نشود. از طرف دیگر مهارها برای فعال شدن نیاز به میزان کمی جابجایی دارند و این مسئله با تغییر نوع مهار مارپیچ قابل برطرف کردن نیست. در نهایت مشخص شد که سطح لغزش ایجاد شده در دیوار مهار مارپیچ با استفاده از سربار سبک، سهمی شکل است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Physical modeling for evaluating the effect of helical anchor configuration and surcharge on wall displacement

نویسندگان [English]

  • Javad Nazariafshar 1
  • Mohammad Emad Mahmoudi Mehrizi 2
  • Younos Daghigh 3
1 Assistant Professor, Department of Civil Engineering, Shahr-e-Qods Branch Islamic Azad University, Tehran, Iran
2 Campus international of Kharazmi University, Tehran, Iran
3 Assisstant professor in department of Civil Engineeering, Islamic Azad University- Karaj, Iran
چکیده [English]

 Helical anchors with unique characteristics have several applications in constructing and reforming the foundations, as well as soil improvement. However, a limited number of study has been done on the use of helical anchors in walls and slopes stability. In the performed studies, the behavior of the helical anchor’s wall was investigated. For this purpose, a laboratory study was designed to evaluate the wall stability with three types of helical anchors and two types of back-slopes in sandy soil. The aim of the study was to investigate the effect of anchor’s shape and the back slope above the wall on the wall crest displacement. To increase the accuracy of measurements and determine the shear strains, photogrammetry and particle image velocimetry (PIV) methods were employed. Finally, to evaluate its implementation potential, the results were compared with those of the nailing method. The results of modeling revealed that an increase in diameter and the number of the helices led to decreasing in wall crest displacement. The reduction percentages were 30% and 60% respectively for increased diameter and increased number of helices and diameter. If the significant reduction in displacement is required, it is suggested to increase the number of helices without any changes in their diameter. Besides, anchors need a small amount of displacement to be activated and this issue cannot be solved by changing the type of helical anchor. Finally, the results indicated that the slip surface created on the wall of helical anchor using light surcharge is parabolic in shape.

کلیدواژه‌ها [English]

  • Helical anchor: Wall: Horizontal displacement: Back slope: Particle image velocimetry

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نشریه مهندسی عمران امیرکبیر
دوره 52، شماره 10
دی 1399
صفحه 2529-2548

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