ارزیابی رفتار لرزه‌ای پی سطحی مجاور شیب به کمک شبیه سازی های عددی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشجوی دکتری، گروه مهندسی عمران، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران

2 استادیار، گروه مهندسی عمران، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران

3 استادیار، گروه مهندسی عمران، دانشگاه رازی، کرمانشاه، ایران

چکیده

کاهش ظرفیت باربری استاتیکی و لرزه‌ای از مهمترین مشکلات پی‌های واقع در مجاورت یا درون شیب است. همچنین راه حل‌های تحلیل حدی ارائه شده در مطالعات پیشین متمرکز بر راه حل کران بالا هستند. اما در این مطالعات، اثر بارگذاری لرزه‌ای واقعی همانند اثرات فرکانس بارگذاری، دامنه‌ی شتاب بالای 0.3g در حوزه‌ی زمان، تحلیل‌های دینامیکی غیر-خطی و ... درنظر گرفته نشده است. برای این منظور در این مقاله رفتار لرزه‌ای پی‌های سطحی در مجاورت تاج شیب ماسه‌ای مطالعه می‌شود. برای مدلسازی عددی مسأله‌ی تحقیق از روش اجزای محدود دو بعدی و چارچوب محاسباتی کرنش مسطح استفاده شده است. پی‌های سطحی در فاصله‌ی مجاورت مشخصی نسبت به تاج شیب قرار داده شده اند. شیب مورد مطالعه در این تحقیق، شیبی با زاویه‌ی 25 درجه (شیب 2:1 قائم به افقی) است. شیب مورد تحلیل از مصالح ماسه‌ای با تراکم متوسط تشکیل شده است. مدل‌های رفتاری ارتجاعی خمیری کامل موهر-کولمب (MC) و خاک سخت شونده (HSM) برای بررسی اثر سخت شوندگی مصالح خاکی شیب درنظر گرفته شده اند. در این مطالعه، رفتار لرزه‌ای واقعی شیب، پی سطحی و جهت پاسخ‌های لرزه‌ای مورد بررسی قرار گرفته است. نتایج تحقیق نشان می‌دهد که دو مدل رفتاری MC و HSM پاسخ‌های کاملا متفاوتی در دو حوزه‌ی رفتار المان سازه ای پی سطحی و عملکرد ژئوتکنیکی شیب ماسه‌ای خشک بدست می دهند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Seismic Behaviour of Shallow Foundation Adjacent to Slope Evaluation by Numerical - Laboratory Methods

نویسندگان [English]

  • Sahar Jalili 1
  • Hossein Javaheri Koupaei 2
  • Hassan Sharafi 3
1 Ph.D. Student, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 Assistant Professor, Department of Civil Engineering, Science and Research Branch,Islamic Azad University,Tehran,Iran
3 Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran
چکیده [English]

Seismic behaviour of shallow foundation on adjacent of the sand slope crest is evaluated in this article. The foundation of various engineering structures has been made of Shallow foundation adjacent to soil slopes. While the shallow foundation is placed in the slope or out of the slope the amount of static and dynamic bearing capacity is reduced. Static bearing capacity and dynamic bearing capacity (Seismic) have been made up of respective coefficients. In fact, when the ground slope is increased the quantitative amount of bearing capacity coefficient of shallow foundation is reduced. Bearing capacity of the shallow foundation has been investigated by various researchers. Respective researchers evaluate this problem when respective shallow foundation is on the slope in static circumstance. In respective condition, the sloe and shallow foundation are under seismic vertical, horizontal loads as well as the combination of respective loads. Seismic vertical and horizontal load effect analysis under horizontal and vertical seismic load condition could be evaluated by critical state methods in quasi-static loading technique. Two-dimensional finite element method, as well as the computational framework of the plane surface, have been used for numerical simulation in current research hypothesis. Shallow foundations have been placed at a certain distance from slope crest. The slope studied in this research has a 25-degree angle (2:1 - V: H).The respective slope has been constructed by sandy materials with medium density. Constitutive elastic models such as Mohr-Coulumb (MC) and Hardening Soil Model (HSM) have been selected for hardening effect evaluation. Actual seismic behaviour of the slope, shallow foundation as well as the direction of seismic response have been investigated innovatively. Research results are presented that two constitutive models (MC and HSM) have completely different response in the zone of the structural element of shallow foundation behaviour and geotechnical performance of dry sandy slope.

کلیدواژه‌ها [English]

  • Shallow foundation
  • Dry Sandy Slope
  • Seismic Loading
  • Numerical Model
  • Physical Model
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