تاثیر دما بر رفتار نشست‌پذیری خاک ریزدانه تثبیت شده با سیمان

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی عمران - دانشکده فنی و مهندسی گرگان - دانشگاه گلستان- گرگان-ایران

2 گروه مهندسی عمران- دانشکده فنی و مهندسی گرگان- دانشگاه گلستان- گرگان

3 گروه مهندسی عمران - دانشگاه غیر انتفاعی میرداماد گرگان-گرگان-ایران

چکیده

در این پژوهش به بررسی آزمایشگاهی تاثیر دما بر خصوصیات نشست پذیری خاک ریزدانه بهسازی شده با سیمان پرداخته شده است. بدین منظور آزمون­های آزمایشگاهی از قبیل آزمایش تراکم استاندارد و آزمایش تحکیم حرارتی انجام گردیده است. آزمایش تحکیم حرارتی با طراحی و ساخت سلول دستگاه تحکیم حاوی ترموکوپل حرارتی و دماسنج جهت انجام آزمایش بر روی نمونه­های مختلف حاوی سیمان تحت زمان­های عمل­آوری متفاوت صورت پذیرفت. نمونه­ها تحت دماهای 30، 45 و 60 درجه سانتی­گراد با مقادیر مختلف سیمان شامل 4، 6 و 8 درصد تحت زمان­های عمل­آوری 7 و 28 روز مورد مطالعه قرار گرفتند. نتایج نشان دادند تحکیم حرارتی بر روی مخلوطهای مختلف خاک­-سیمان باعث بهبود شرایط نشست پذیری خاک شده است. در این ارتباط با افزایش دما از 20 (دمای محیط) به 60 درجه سانتی­گراد، نشست خاک افزایش یافته و با افزایش مقدار سیمان از 4 به 8 درصد نشست خاک نیز کاهش یافته است. همچنین با افزایش زمان عمل­آوری از 7 به 28 روز تحت دما و درصد سیمان مشخص، شاخص فشردگی کاهش معناداری یافته است. همچنین می­توان پی برد کمترین مقدار شاخص فشردگی نمونه­ها مربوط به نمونه حاوی 8 درصد سیمان با زمان عمل­آوری 28 روز در دمای 30 درجه سانتی­گراد بوده و بیشترین شاخص تورم نیز در نمونه­ خاک طبیعی رخ داده است. نتایج نشان دادند که در نمونه­های تحت زمان عمل­آوری ۷ روز و دمای ۳۰ درجه سانتی گراد، با افزایش مقدار سیمان از ۴ به ۸ درصد، مقادیر شاخص فشردگی و تورم نمونه­ها به ترتیب در حدود ۱۴ و 30 درصد کاهش یافته­اند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The Effect of Temperature on the Settlement Behavior of Fine-Grained Soil Stabilized with Cement

نویسندگان [English]

  • Seyedeh Shokoofeh Yousefi 1
  • Alireza Tabarsa 2
  • Younes Bagheri 3
1 Depatrment of Civil Engineering, Faculty of Engineering, Golestan University, Gorgan, Iran.
2 Depatrment of Civil Engineering, Faculty of Engineering, Golestan University, Gorgan, Iran.
3 Faculty of Engineering, Mirdamad Institute of Higher Education, Gorgan, Iran.
چکیده [English]

In this research, heat effects on settlement characteristics of cement-stabilized fine-grained soil have been considered in laboratory using standard compaction and thermal consolidation tests. Thermal consolidation tests were conducted by designing a consolidation cell instrument equipped with thermocouple and thermometer on different cement-stabilized samples at various curing times. Samples were tested at temperatures of 30, 45 and 60 0C; cement contents of 4, 6 and 8 percent; and curing times of 7 and 28 days. According to the results, consolidation will be improved in cement-stabilized soils if heat is used. Moreover, settlement time decreases and consolidation speed increases. The results also show that increasing temperature from 20 0C (room temperature) to 60 0C may increase soil settlement. This is while increasing cement content from 4 to 8 percent leads to decrease soil settlement. Besides, increasing curing time from 7 to 28 days under specific temperature and cement content, causes a significant decrease in soil compression index. Among different samples investigated in this research, the minimum compression index was observed in 28 day-cured specimens reinforced with 8 percent cement at temperature of 30 0C while the maximum swelling index was observed in natural soil. The findings also revealed that in 7 day-cured specimens under temperature of 30 0C with increasing cement content from 4 to 8 percent, compression and swelling index values have been decreased to 14 and 30 percent, respectively.

کلیدواژه‌ها [English]

  • Soil improvement
  • Thermal consolidation
  • Cement
  • Compression index
  • Swelling index
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