بررسی تأثیر دما بر مقاومت برشی زهکش نشده رس کائولینیت

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه زمین شناسی مهندسی و تکتونیک، دانشکده زمین شناسی، پردیس علوم، دانشگاه تهران

2 گروه زمین شناسی و تکتونیک، دانشکده زمین شناسی، پردیس علوم ، دانشگاه تهران

3 تهران، دانشگاه تهران، دانشکده علوم، گروه زمین شناسی مهندسی

چکیده

بررسی تغییر دما بر مقاومت خاک یکی از موضوعاتی است که در دهه‌های اخیر مورد توجه بسیاری  از محققین قرار گرفته است. در تحقیق حاضر به منظور بررسی تأثیر دما بر مقاومت برشی زهکش نشده (Cu)خاکهای رسی، ابتدا سلولی با قابلیت تغییر و ثابت نگه داشتن دمای نمونه در طول بارگذاری، طراحی و ساخته شد. پس از تعیین ویژگی‌های شاخص نمونه‌ای از خاک رس کائولینیت، آزمایش تعیین مقاومت برشی زهکش نشده بر روی خاک اشباع در دماهای 10 ،20 ،30 ،40 ،50 ،60 و70 درجه سانتی گراد انجام گردید. با تکرار آزمایش بر روی نمونه هایی با ویژگی های ثابت و در دمای مشخص تکرارپذیری نتایج تأیید شد. نتایج نشان می‌دهد با افزایش دما، Cu کائولینیت کاهش یافته بطوریکه افزایش دما از 10 درجه به 70 درجه سانتی گراد باعث کاهش مقدار Cu از 26/6 به 10/94 کیلوپاسکال شده است. بر این اساس، در محدوده دمایی مورد مطالعه رابطه ای تجربی بین دما و Cu( با ضریب تعیین 0/96 )برای رس مورد مطالعه پیشنهاد شد. شکل کلی منحنیهای تنش – کرنش نمونه ها در دماهای مختلف یکسان بوده و در کرنش 20 %بصورت خطی در می‌آیند. افزایش دما باعث کاهش محدوده تغییر شکل الاستیک و افزایش محدوده تغییر شکل پلاستیک نمونه ها شده و زاویه صفحه گسیختگی با افق، با افزایش ( AES )نشان دهنده افزایش آن با افزایش دما کاهش می‌یابد. اندازه‌گیری تنش ناشی از انبساط محوری نمونه دما است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Investigation of the Effect of Temperature on the Undrained Shear Strength of Kaolinite

نویسندگان [English]

  • Akbar Cheshomi 1
  • Fariborz Mohammadi 2
  • Alimohammad Rajabi 3
1 Department of Structural and Engineering Geology, School of Geology, College of Science, University of Tehran
2 Department of Structural and Engineering Geology, School of Geology, College of Science, University of Tehran
3 Department of Structural and Engineering Geology, School of Geology, College of Science, University of Tehran
چکیده [English]

Investigation of the effect of temperature on soil strength is one of the issues which has been considered by many researchers in recent decades. In this study to investigate the effect of temperature on the undrained shear strength (Cu) of clay soils, a cell with the capability of both changing and keeping fixed the temperature of sample, was designed and constructed. After determining the index properties of samples for Kaolinite clay soil, undrained shear strength (Cu) test was carried out on saturated clay soil at 10, 20, 30, 40, 50, 60 and 70 ° C. Repeatability of the results was confirmed by repeating tests on samples with the same properties a given temperature. The results showed that by increasing the temperature, the Cu values decreased so that, as the temperature raised from 10 ° C to 70 ° C, the values Cu were reduced from 26.6 to 10.94 kPa. Accordingly, in the studied temperature range, an empirical relationship between temperature and Cu (with R2 = 0.96) was proposed. The general shape of the stress–strain curves of the samples in different temperature was the same and in strain level of 20% was linear. Increasing the temperature caused to decline in the range of elastic deformation and enhancement in the range of plastic deformation of the samples; in addition, by increasing the temperature, the angle of the failure plane was decreased. The measurement of axial expansion stress (AES) indicated enhancement of the stress by increasing the temperature.

کلیدواژه‌ها [English]

  • temperature
  • kaolinite
  • undrained shear strength
  • clay soil
  • failure

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 52، شماره 8
آبان 1399
صفحه 1971-1982

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