نوع مقاله: علمی - پژوهشی

نویسندگان

1 دانشجوی فارغ التحصیل کارشناسی ارشد دانشگاه ارومیه

2 دانشیار دانشگاه ارومیه

چکیده

در این تحقیق تأثیر سه حالت عمده زبری ناپیوستگی‌ها به صورت دندانه‌دار، زبر موجدار و صفحه‌ای صاف با جهت‌یافتگی مختلف نسبت به فشار جانبی بر مقاومت سنگ تحت تنش‌های سه محوری مورد بررسی قرار گرفته است. 15 گروه نمونه‌های دارای سه نوع زبری سطح ناپیوستگی و دارای پنج نوع شیب از صفر تا 90 درجه با موفقیت آماده‌سازی شده و مقاومت هر گروه تحت تنش‌های سه محوری در فشارهای جانبی مختلف اندازه‌گیری شده است. نتایج نشان می‌دهد که با افزایش زاویه شیب ناپیوستگی از 30 تا 45 و 60 درجه تحت فشار جانبی ثابت مقاومت محوری نمونه‌های دارای ناپیوستگی صاف شدیداً کاهش می‌یابد. اما مقاومت محوری ناپیوستگی‌های زبر موجدار و دندانه‌دار با افزایش زاویه شیب از 30 تا 45 درجه تحت فشار جانبی ثابت نسبت به ناپیوستگی دارای صفحه‌ای صاف به مقدار کمتری کاهش می‌یابد و در کل مقاومت ناپیوستگی دارای صفحه‌ای صاف دارای جهت یافتگی مختلف و تحت تغییرات فشار جانبی کمتر از ناپیوستگی‌های زبر موجدار و دندانه‌دار است. برای نمونه‌های دارای ناپیوستگی‌های زبر موجدار و دندانه‌دار در شیب 30 درجه شکست در سنگ سالم اتفاق افتاد. در صورتی که برای نمونه‌های دارای ناپیوستگی‌های دندانه‌دار در شیب 45 درجه به ویژه تحت فشار جانبی بیشتر، نیز شکست در سنگ سالم اتفاق افتاد. همچنین در نمونه‌های دارای ناپیوستگی‌های دندانه‌دار در شیب 60 درجه تحت تنش یک محوری لغزش در یک طرف سطوح دندانه‌ها اتفاق افتاده و باعث جابجایی دو صفحه کلی ناپیوستگی گردید. اما با افزایش فشار جانبی دندانه‌ها شکسته شدند. نسبت مقاومت محوری حداکثر به مقاومت محوری حداقل سنگ (Rtriax) دارای حداکثر مقدار برای فشار جانبی صفر بوده و به صورت تابع توانی منفی ابتدا با افزایش فشار جانبی به شدت کاهش یافته سپس به مقدار ثابتی نزدیک می‌شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effect of discontinuities roughness having different slope angles on the strength of jointed rock under triaxial stresses

نویسندگان [English]

  • Fatemeh Aminpoure 1
  • Hassan Moomivand 2

1 M.Sc. Mining Engineering Department, Urmia University

2 Associate Professor of Urmia University

چکیده [English]

Effect of discontinuities roughness including tooth-shaped asperity, rough undulating and smooth plane having different orientations respect to confining pressure on the strength of rock under triaxial stresses has been investigated in this research. 15 groups of specimens having three types of discontinuities roughness and five types of slope angles from 0 to 90 degrees have been successfully prepared and tested under triaxial stresses. The axial strength of rough undulating and tooth-shaped asperity discontinuities decreases a little with increasing slope angle from 30 to 45 degrees under constant confining pressure and in general the axial strength of smooth plane discontinuities having different orientations is less than the axial strength of rough undulating and tooth-shaped asperity discontinuities under the different confining pressures. For tooth-shaped asperity discontinuities having orientation angles 45 degrees, failure also occurred at the body of the specimens particularly with increasing the confining pressure. Sliding occurred at the one side of tooth-shaped asperities of discontinuity having orientation angles of 60 degree under uniaxial loading and displacement took place at the direction of discontinslopeuities. But tooth-shaped asperities were broken along the discontinuities under the higher confining pressures. The effect slope angle on the axial strength decreases with an increase of confining pressure and rate of reducing the axial strength increases with an increase of discontinuity roughness. As, the strength of specimens having very rough discontinuities under high confining pressures approaches to the strength of massive (intact) rock. The maximum axial strength to the minimum axial strength ratio (Rtriax) has high value for the zero confining pressure and it decreases sharply as a negative power function of confining pressure then approaches to a constant value.

کلیدواژه‌ها [English]

  • discontinuity"
  • roughness"
  • slope angle"
  • model material"

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