اثر بارگذاری ترکیبی بر ظرفیت باربری پی‌ نواری مستقر بر خاک دو لایه رسی مجاور شیب‌ مسلح با ژئوگرید

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی عمران و محیط زیست، دانشگاه صنعتی شیراز، شیراز، ایران

2 گروه مهندسی عمران، واحد شهر کرد، دانشگاه آزاد اسلامی، شهر کرد، ایران

3 عضو اصلی کمیسیون تخصصی ژئوتکنیک، سازمان نظام مهندسی ساختمان، تهران، ایران

چکیده

هدف مقاله حاضر تعیین ظرفیت باربری زهکشی‌نشده پی‌های نواری مستقر بر خاک‌های دولایه رسی در مجاورت یک شیب مسلح‌شده با ژئوگرید تحت اثر بارگذاری‌های ترکیبی با اعمال بارهای افقی (H)، قائم (V) و لنگر خمشی (M) می‌باشد. به همین منظور با مدلسازی المان محدود در نرم‌افزار آباکوس و انجام تحلیل برمبنای روش بار-جابجایی کنترل شده، پوش‌های گسیختگی و مکانیزم گسیختگی خاک زیر پی در فضاهای بارگذاری V-H، V-M و V-H-M تعیین شد. نتایج حاصله در دو حالت شیب‌های فاقد تسلیح و مسلح‌شده با لایه‌های ژئوگرید و با انجام مطالعات پارامتریک درخصوص اثر تغییرات نسبت‌های مقاومت زهکشی‌نشده لایه‌های خاک رسی (Cu1/Cu2) و نسبت ضخامت لایه رسی اول به عرض پی نواری (H1/B) مقایسه شد. نتایج نشان داد که با افزایش Cu1/Cu2 در بارگذاری V-H، ظرفیت باربری قائم افزایش یافته که ناشی از افزایش چسبندگی زهکشی‌نشده لایه اول است. همچنین در بارگذاری‌های ترکیبی V-H و V-M در حالتی که تنها بارگذاری قائم وجود داشته باشد، حجم بیشتری از خاک دچار گسیختگی می‌شود. همچنین نتایج نشان داد که تسلیح شیب با ژئوگرید به‌ترتیب باعث افزایش 31 و 35 درصدی ظرفیت باربری قائم و ظرفیت لنگر خمشی پی می‌گردد. بطور کلی یافته‌های این مطالعه بینش جدیدی را از مکانیزم گسیختگی پی‌های نواری مستقر بر خاک‌های دولایه رسی در مجاورت شیب‌های مسلح‌شده با ژئوگرید تحت اثر بارگذاری‌های ترکیبی فراهم می‌نماید.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The effect of combined loading on the bearing capacity of strip footings located on two-layered clayey soils adjacent to geogrid-reinforced slopes

نویسندگان [English]

  • Meisam Mahboubi Niazmandi 1
  • Sohrab Mirasi 2
  • Mehdi Hashemi jokar 3
  • Mohammad Momeni 2
1 Department of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran
2 Department of Civil Engineering, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
3 The main member of the specialized geotechnical commission, the organization of the construction engineering system
چکیده [English]

The present paper aims to determine the undrained bearing capacity of strip footings located on two-layered clayey soil in the vicinity of a geogrid-reinforced slope under the effect of combined loading by applying horizontal (H), vertical (V), and bending moment (M) loads. To this aim, by finite element modeling in ABAQUS based on the controlled load-displacement method, the failure envelopes and the failure mechanism of the subsoil of strip footings under the effect of combined loadings were determined in V-H, V-M, and V-H-M loading spaces. The results obtained in two cases of unreinforced and reinforced slopes with geogrids were compared by performing parametric studies regarding the effect of changes in undrained shear strength ratios of clayey layers (Cu1/Cu2) and the ratio of the thickness of the first clay layer to the width of the strip foundation (H1/B). The results showed that by increasing Cu1/Cu2 in V-H loading spaces, the vertical bearing capacity increased, which is caused by the increase in the undrained cohesion of the first layer. Furthermore, in scenarios involving both vertical-horizontal (V-H) and vertical-moment (V-M) load combinations, when subjected solely to vertical loading, a greater volume of soil experienced failure. The results showed that reinforcing the slope with geogrid increases the vertical and the moment bearing capacity by 31 and 35%, respectively. In general, the findings of this study provide new insight into the failure mechanism of strip foundations based on two-layered clayey soils in the vicinity of geogrid-reinforced slopes under the effect of combined loads.

کلیدواژه‌ها [English]

  • Finite element analysis
  • strip footings
  • two-layer clayey soil
  • geogrid-reinforced slope
  • combined loading

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 55، شماره 9
آذر 1402
صفحه 1825-1844

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