ارزیابی تحکیم و پدیده شکست ذرات مصالح سنگریزه ضعیف در دستگاه ادومتر با مقیاس متوسط

نوع مقاله : پژوهشی اصیل (کامل)

نویسندگان
1 دانشیار دانشکده مهندسی عمران و محیط زیست دانشگاه تربیت مدرس
2 دانشجوی دانشکده مهندسی عمران و محیط زیست دکتری دانشگاه تربیت مدرس
چکیده
مصالح سنگریزه ای مصالحی هستند که کاربرد فراوانی در پروژه های عمرانی مانند سد سازی ، راهسازی، اسکله ها و .... دارند . با توجه به گسترش روزافزون استفاده از این مصالح آزمایشات و مطالعات شناسایی زیادی نیز روی این مصالح انجام گرفته است. معمولاً این مطالعات بر روی سنگریزه های متوسط و قوی که دارای مقاومت فشاری بالای 50 مگاپاسکال می باشند، انجام گرفته است. امروزه به دلیل کاهش هزینه و حفاظت از محیط زیست استفاده از سنگریزه های نرم و ضعیف که دارای مقاومت فشاری پایین تر از 50 مگاپاسکال می باشند، افزایش یافته است. هنوز مطالعات کامل و جامعی بر روی سنگریزه های نرم انجام نگرفته است و نیاز به کسب اطلاعات بیشتر در زمینه رفتار این مصالح در شرایط مختلف می باشد. با توجه به اینکه ابعاد سنگریزه های قابل استفاده در محل ممکن است خیلی بزرگتر از ابعاد دستگاههای آزمایشگاهی باشد، بنابراین مقیاس کردن و تطابق نتایج بدست آمده از آزمایشگاه و محل از نکات مهم در مورد مصالح سنگریزه است. در این تحقیق رفتار مصالح سنگریزه ای ضعیف در شرایط مختلف در دستگاه ادومتر با مقیاس متوسط مورد بررسی قرار گرفته است. نتایج این مطالعات نشان دهنده این است که حضور آب باعث افزایش نشست و همچنین افزایش پدیده شکست ذرات می شود. بیشترین مقدار کرنش و تغییر شکل برای نمونه ها در اولین روز بارگذاری اتفاق می افتد و در هر روز بارگذاری، بیشترین مقدار تغییر شکل در چند ساعت اولیه اتفاق می افتد.

کلیدواژه‌ها

موضوعات


عنوان مقاله English

Settlement and Particle Breakage of Soft Rockfill Materials in Medium Scale Oedometer

نویسندگان English

Ali Komak panah 1
Hamidreza Rahmani 2
1 Associate Professor, faculty of civil and environmental engineering, Tarbiat Modares University
2 Phd candidate, faculty of civil and environmental engineering, Tarbiat Modares University, Tehran
چکیده English

Rockfill materials are used in construction projects such as dam construction, road construction and so on. Due to the increasing use of these materials, experiments and studies have also been carried out on this material and usually, these studies have been carried out on strong rockfill materials. Today, the use of soft and weak rockfill materials has expanded because the economic and environmental issues. These marginal materials traditionally would not be used owing to their unfavorable engineering properties that is, low strength, high compressibility, and proneness to material degradation with time. Therefore, the use of soft rocks excavated on site as rockfill materials for high rockfill dams is still a controversial issue, as weathering takes place when the rock is exposed to an environment in which variations in air, temperature, and water content are involved. and still no comprehensive studies have been conducted on soft rockfill materials and need more information on the behavior of these materials in different conditions. One of the most important subject discussed in the rockfill materials is the particle breakage phenomena. Particle breakage index that quantifies the degree of particle breakage, can reflect the degree of particle crushing of material. To select weak rockfill materials, we visited the Nohob dam that is under construction and rockfill material in spillway excavation section is thrown away and it is not used in the construction of the dam. With considering that the dimensions of the usable rockfill material may be much larger than the dimensions of the laboratory equipment. Therefore, it is always a matter of scaling and matching the results of the laboratory and the field from the important items of rockfill materials. In this research, the behavior of weak rockfill materials has been studied in medium scale oedometer apparatus, in dry, wet and saturate conditions and also Los Angeles experiment is done. Based on the present study, the particle breakage increases with the addition of water and in saturate conditions, particle breakage also has a slight increase compared to wet conditions and for settlements and deformations of wet and dry specimens of materials show that wet specimens settlements are more than dry specimens.

کلیدواژه‌ها English

Particle Breakage
Weak Rockfill Material
Medium Scale Oedometer
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