مطالعه عددی آزمایش نفوذ پیزوکن در خاک‌ ماسه‌ای فیروزکوه با شرایط زهکشی مختلف

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران

چکیده

آزمایش نفوذ پیزوکن یکی از رایج­ترین آزمایش ­های میدانی است که از آن، به ­منظور اندازه ­گیری فشار آب منفذی، شناسایی لایه ­بندی خاک و تخمین پارامترهای ژئوتکنیکی زمین استفاده می­ شود. بسته به نوع خاک که در محدوده رس تا ماسه قرار گرفته، شرایط زهکشی ­شده، زهکشی ­نشده و یا زهکشی جزئی می تواند در حین فرایند نفوذ رخ دهد. در خاک­ های لای‌دار و ترکیب رس- ماسه، وجود شرایط زهکشی جزئی در آزمون پیزوکن محتمل است، که اغلب در تفسیرهای آزمایش، از این موضوع صرف­نظر می ­شود. در ادبیات فنی، بررسی تأثیر شرایط زهکشی بر نتایج آزمایش پیزوکن عمدتاً به ­صورت آزمایشگاهی یافت می‌شود، و مطالعات عددی که بتواند مدل­سازی قابل قبولی از پیچیدگی های این آزمون مانند اندرکنش خاک-مخروط، اندرکنش آب-خاک، تغییر شکل­ های بزرگ و اثر رفتار غیرخطی خاک را ارائه دهد، به­ ندرت انجام شده است. در این مقاله، به­ کمک نرم ­افزار المان محدود آباکوس و با استفاده از مدل رفتاری پیشرفته هایپوپلاستیک تغییر شکل­ های بزرگ و رفتار غیرخطی خاک در حین فرآیند نفوذ مدل­سازی و رفتار خاک ماسه­ ی اشباع فیروزکوه در شرایط زهکشی و درصد تراکم ­های مختلف تحلیل شد. سپس با استفاده از نتایج به ­دست آمده، محدوده تأثیر نفوذ مخروط بر خاک اطراف و محدوده شرایط زهکشی جزئی برای خاک ماسه ­ای فیروزکوه بررسی شد. همچنین نشان داده شد که شرایط زهکشی و درصد تراکم خاک تأثیر قابل ملاحظه ­ای بر روند تغییرات اضافه فشار آب منفذی در خاک اطراف مخروط دارد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

A numerical study of piezocone test in Firoozkooh sandy soil under different drained conditions

نویسندگان [English]

  • Mohammad Javad Mashin chian
  • mohammad mehdi ahmadi
Ph.D Candidate in Geotechnical Engineering, Faculty of Civil Engineering, Sharif University of Technology, Tehran, Iran.
چکیده [English]

The piezocone penetration test is commonly used to measure pore water pressure, identify soil profiles and estimate their material properties. Depending on the soil type, ranging from clay to sand, undrained, partially drained, or drained conditions may occur during cone penetration. In silt and sand–clay mixtures, the piezocone penetration is characterized by partially drained conditions, which are often neglected in data interpretation. The effect of drainage on piezocone measurements has been mainly studied experimentally. Numerical analyses are rare because taking into account large soil deformations, soil–water and soil–structure interactions, and nonlinear soil behavior are still challenging tasks. In this paper, using an advanced hypoplastic constitutive model and ABAQUS finite element software, large deformations and nonlinear behavior of soil during penetration were modeled, and the behavior of Firoozkooh saturated sandy soil having different drainage conditions and relative densities were analyzed. Then, using the obtained results, the range of influence of cone penetration on the surrounding soil and the range of partial drainage conditions for Firoozkooh sandy soil were investigated. It was also shown that drainage condition and density of the soil had a significant effect on the affected soil area and the trend of changes in excess pore water pressure.

کلیدواژه‌ها [English]

  • Piezocone Test
  • Partial Drainage
  • Numerical Modeling
  • ABAQUS Software
  • Hypoplastic constitutive model

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نشریه مهندسی عمران امیرکبیر
دوره 54، شماره 10
دی 1401
صفحه 3637-3656

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