تاثیر مشخصات هندسی شمع بر پاسخ لرزه‌ای آن با استفاده از مدل‌سازی عددی غیرخطی سه‌بعدی

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران

چکیده

رفتار سیستم خاک - شمع تحت بار لرزه‌ای، وابسته به عوامل متعددی است. این عوامل را می‌توان به سه دسته اصلی شامل مشخصات هندسی شمع، مشخصات مکانیکی خاک اطراف شمع و نیز ویژگی‌های بارگذاری لرزه‌ای طبقه‌بندی نمود. هدف تحقیق حاضر بررسی تاثیر مشخصات هندسی شمع بر پاسخ سیستم خاک-شمع با در نظر گرفتن رفتار غیرخطی محیط خاک تحت بار لرزه‌ای است. بدین منظور، مطالعه عددی سه‌بعدی کاملا غیرخطی در حوزه زمان با استفاده از نرم‌افزار تفاضل محدود FLAC3D صورت گرفت. تمرکز مقاله حاضر بر روی پاسخ دینامیکی شمع شناور منفرد مدفون در خاک رسی بوده و مطالعه پارامتریک برای بررسی تاثیر مشخصات هندسی شمع در پاسخ آن صورت گرفته است. به منظور در نظر گرفتن رفتار غیرخطی خاک تحت بار لرزه‌ای، مدل رفتاری الاستوپلاستیک  برای محیط خاک اعمال شد و هم‌چنین با اعمال تابع کاهش مدول برشی خاک با افزایش کرنش برشی، کاهش سختی خاک تحت بار لرزه‌ای شبیه‌سازی شد. نتایج این تحقیق نشان دادند که با افزایش قطر شمع، مقدار لنگر خمشی بیشینه ایجاد شده در شمع تحت بار لرزه‌ای به صورت قابل توجهی افزایش می‌یابد و این افزایش متناسب با توانی از قطر شمع است. هم‌چنین بررسی نتایج آنالیزهای عددی صورت گرفته نشان داد که تاثیر طول شمع بر بیشینه لنگر خمشی ایجاد شده در شمع چندان قابل توجه نیست؛ اما پارامتر طول شمع تاثیر قابل توجهی بر شکل دیاگرام توزیع لنگر خمشی در شمع و نیز مکان رخداد لنگرخمشی بیشینه دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Nonlinear Three-Dimensional Numerical Study of Pile Seismic Behavior: Effect of Pile Geometrical Parameters

نویسندگان [English]

  • Sadjad Hadei
  • Mohammad Mehdi Ahmadi
Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
چکیده [English]

The behavior of soil-pile systems subjected to earthquake loading depends on many parameters. These parameters can be categorized into three main groups: geometrical parameters of the pile, soil mechanical properties, and loading characteristics. The purpose of this study is to investigate the effect of pile geometrical parameters on the seismic response of soil-pile systems considering soil nonlinear behavior. To this aim, a set of fully nonlinear three-dimensional analyses in the time domain was conducted using the finite difference computer program FLAC3D. The focus of the paper is on the seismic response of the floating single pile embedded in clayey soil and the parametric study was performed to investigate the effect of pile geometrical parameters on its seismic response. To consider soil nonlinear behavior during seismic events, an elastoplastic constitutive law was applied to the soil medium. Also, soil shear modulus reduction with the increase in soil shear strain level was simulated. The results of this study showed that an increase in pile diameter causes an increase in the maximum kinematic bending moment. This increase is proportional to the pile diameter powered by a value. Also, the results showed that effect of pile length on the magnitude of maximum bending moment in pile was not significant. However, the shape of the bending moment distribution diagram and location of the maximum bending moment are strongly affected by pile length.

کلیدواژه‌ها [English]

  • Clayey soil-pile interaction
  • 3D Numerical modeling
  • Soil nonlinear behavior
  • Analyses in the time domain
  • Pile geometrical parameters
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