مدل‌سازی عددی تاثیر فاصله‌داری و زاویه داری درزه Y شکل نزدیک بار کششی میل مهار بر رشد ترک

سرفرازی, وهاب; عجم زاده, محمدرضا

doi:10.30479/jmre.2019.8968.1140

مدل‌سازی عددی تاثیر فاصله‌داری و زاویه داری درزه Y شکل نزدیک بار کششی میل مهار بر رشد ترک

نوع مقاله : یادداشت فنی

نویسندگان

¹ استادیار، گروه مهندسی معدن، دانشگاه صنعتی همدان

² کارشناسی ارشد استخراج معدن، گروه مهندسی معدن، دانشگاه صنعتی همدان

10.30479/jmre.2019.8968.1140

چکیده

ابعاد حفریات زیرزمینی یکی از پارمترهای کلیدی در پایداری آن است. در توده‌سنگ‌های ضعیف، حفریات بزرگ زمان پایداری کمی دارند بطوری که این زمان از زمان نصب نگهداری کمتر است. راک‌بولت‌ها به عنوان یکی از سیستم‌های نگهداری در پایدارسازی پروژه‌های مهندسی سنگ کاربرد دارند. نقش اصلی راک‌بولت‌ها، افزایش مقاومت زمین است. عملکرد راک‌بولت‌ها به کیفیت نصب آن‌ها بستگی دارد. با استفاده از روش‌های کشش راک‌بولت و تست گشتاور می‌توان از کیفیت نصب راک‌بولت مطلع شد. شبیه‌سازی‌های عددی از دیگر از روش‌هایی است که برای مطالعه رفتار راک‌بولت کاربرد دارند. در این روش‌ها می‌توان رفتار پیچیده راک‌بولت را که با مطالعه آزمایشگاهی امکان‌پذیر نیست، مطالعه کرد. در این مقاله سعی شده است که با استفاده از نرم‌افزار franc 2d تاثیر نیروی وارده از طرف راک‌بولت بر روی درزه Yشکل مدلسازی شود. زاویه درزه بزرگ نسبت به افق (β) صفر، 45 و 90 درجه است. زاویه درزه کوچک نسبت به درزه بزرگ (α)، 20، 40، 60، 80، 100، 120، 140 و 160 درجه است. فاصله درزه از مرکز محل اعمال نیرو 2a، 3a و 4a است که a طول درزه بزرگ است. در این پژوهش 52 مدل مورد بررسی قرار گرفت. در حالتی که درزه افقی باشد بیشترین و در حالت قائم کمترین رشد درزه دیده می‌شود. بیشترین تعداد رشد درزه نیز در حالتی است که زاویه درزه بزرگ نسبت به افق 45 درجه باشد. بیشترین گسترش رشد شاخه کوچک در حالت افقی و بیشترین تعداد رشد شاخه کوچک درزه نیز در زاویه 45 درجه نسبت به افق اتفاق افتاده است.

کلیدواژه‌ها

موضوعات

مکانیک سنگ

عنوان مقاله [English]

Numerical Simulation of the Effect of Spacing and Angularity of Y Shape Joint Neighboring Rock Bolt Tensile Load on the Crack Growth

نویسندگان [English]

V. Sarfarazi ¹
M.R. Ajamzadeh ²

¹ Assistant Professor, Dept. of Mining, Hamedan University of Technology

² M.Sc Student, Dept. of Mining, Hamedan University of Technology

چکیده [English]

The dimension of underground structure is a key factor in its stability. Rock blotting has important effect in rock mechanic projects. It increases the stability of rock blocks. The performance of rock bolt is depending on the quality of its set up. Quality of its set up is determined by pull out test method. Numerical simulation is other method for determination of rock blotting behavior. In this paper, the effect of tensile loading on the “Y” shape joint is determined using FRANC2D. The angularity of large joint tail (β) changes from 0° to 90° with increment of 45°. The angularity of small joint tail related to large joint tail (α) changes from 20° to 160° with increment of 20°. The spacing between joint and loading place change from 2a to 4a with increment of “a” which “a” is the length of large joint tail. Totally 52 model were simulated. In the case of horizontal joint the crack growth length is maximum and vertical joint has minimum effect on the crack growth. When the angularity of large joint tail related to horizontal was 45°, the maximum of crack growth was occurred. The maximum of crack growth from small joint tail was occurred when it is in horizontal configuration. The maximum number of small joint tail growth occurred when its angularities related to horizontal axis was 45°.

کلیدواژه‌ها [English]

Rock bolt
Y shape joint
Crack growth
Angularity
Spacing

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