تحلیل الگوی شکست ماسه سنگ‌ها (مطالعه موردی: ماسه سنگ‌های استان مرکزی)

نوع مقاله: مقاله پژوهشی

نویسندگان

1 گروه زمین‌شناسی دانشگاه بوعلی سینا همدان

2 گروه مهندسی معدن دانشگاه صنعتی همدان

چکیده

هدف از این پژوهش، تحلیل الگوهای شکست ماسه سنگ‌های دوران مزوزوئیک و سنوزوئیک استان مرکزی با توجه به تغییرات مقاومت فشاری آنها می‌باشد. برای این منظور، الگوهای شکست پنج تیپ مختلف از ماسه سنگ‌های با مقادیر مقاومت فشاری تک‌محوره (UCS) متفاوت حاصل از نتایج آزمایشگاهی و آنالیز عددی مورد بررسی قرار گرفتند. همچنین در این مطالعه اثر الگوهای شکست بر روی مقاومت فشاری تک‌محوره کمی‌سازی گردید. برای انجام این پژوهش نمونه‌های بلوکی از ماسه سنگ‌های سازند‌های مختلف واقع در بخش شمالی استان مرکزی جمع‌آوری و براساس ویژگی‌های بافتی و کانی‌شناسی به پنج تیپ (تیپ‌‌‌‌های 1 تا 5) تقسیم گردیده و تحت آزمایش UCS قرار گرفتند. بررسی الگوهای شکست این ماسه سنگ‌ها در محدوده‌های مختلف مقاومتی نشان داد که در مقادیر پایین مقاومت، الگوی شکست عمدتا از نوع برشی ساده (Simple shear) می‌باشد که با افزایش مقاومت فشاری به نوع کششی چندگانه (Multiple extenssion) تغییر می‌یابد. الگوی غالب شکست برای تیپ‌های 1، 2 و 4 از نوع برشی ساده و برای تیپ‌های 3 و 5 از نوع کششی چندگانه می‌باشد. بررسی الگوهای شکست در بازه‌های مقاومتی مختلف برای کل نمونه‌‌‌‌های ماسه‌سنگی نشان داد که تا مقادیر 140 مگاپاسکال، الگوی شکست غالب از نوع برشی ساده و برای مقادیر بیش از 140 مگاپاسکال، الگوی شکست از نوع کششی چندگانه می‌باشد. همچنین در این مطالعه، الگوهای شکست نمونه‌های آزمایشگاهی با استفاده از نرم‌افزار PFC2D به صورت عددی شبیه‌سازی شدند و ملاحظه گردید که نتایج بدست آمده از مدل‌سازی عددی، همخوانی قابل قبولی با نتایج آزمایشگاهی نشان می‌دهند.

کلیدواژه‌ها


عنوان مقاله [English]

Failure Modes Analysis of Sandstones (Case Study: Markazi Province Sandstones)

نویسندگان [English]

  • mehran nouri 1
  • Gholamreza Khanlari 1
  • Vahab Sarfarazi 2
  • Behrooz Rafiei 1
1 Geology department, Bu-Ali Sina university, Hamedan-Iran
2 mining engineering department, hamedan university of technology
چکیده [English]

The aim of this study is analyzing the failure modes of sandstones related to Markazi Province using compressive strength changes. For this purpose, the fracture modes of five different types of sandstones with different compressive strength values have been studied experimentally and numerically. Also, The effect of failure modes on uniaxial compressive strength was quantified. block samples were collected from different sandstone formations located in northern part of Markazi province. These sandstones were divided into five types based on the textural and mineralogical characteristics. These samples were subjected to uniaxial compressive strength testing. Examination of the fracture modes showed that simple shear mode occurred at low values of strength and it changes to multiple extension mode with increasing the compressive strength. The dominant failure mode for types 1, 2 and 4 is simple shear and for types 3 and 5 is multiple extension. Investigation of failure modes in different strength ranges showed that the dominant failure modes up to 140 and over 140 MPa are simple shear and multiple extension, respectively. Therefore, strength of 140 MPa was considered as the transisson point. Also, in this study, the failure modes of the experimental samples were numerically simulated using PFC2D software. The results of numerical modeling showed a good agreement with the experimental results.

کلیدواژه‌ها [English]

  • sandstones
  • Failure mode
  • UCS
  • PFC2D
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