مطالعه آزمایشگاهی ظرفیت باربری معادل بستر رسی بهسازی شده با ستون سنگی

مهندسی عمران فردوسی

مقاله 5، دوره 38، شماره 3 - شماره پیاپی 51، مهر 1404، صفحه 97-114   

نوع مقاله: مقاله پژوهشی

شناسه دیجیتال (DOI): 10.22067/jfcei.2025.92285.1346

نویسندگان

کریم بهاری امینه^{* 1}؛ سید محمد علی صدرالدینی²؛ محمد هادی علیزاده الیزیی¹

¹گروه مهندسی عمران، دانشگاه آزاد اسلامی واحد رودهن

²گروه مهندسی عمران، دانشگاه آزاد اسلامی واحد اسلامشهر

چکیده

در چند دهه‌ی اخیر، ساخت‌وساز بر روی خاک‌های سُست و مسئله‌دار، چالش‌ها و مشکلات زیادی را پیش‌روی مهندسان ژئوتکنیک قرار داده است. در این میان، روش‌های متعددی برای بهسازی این خاک‌ها مورد استفاده قرار گرفته است. از جمله‌ی این روش‌ها، استفاده از ستون سنگی است که با حذف بخشی از خاک ضعیف و جایگزینی آن با ستون‌های خاک دانه‌ای صورت می‌گیرد. در این تحقیق، بهسازی بستر رسی سست از دو طبقه‌ی CL و CH، با ستون‌های سنگی مورد بررسی قرار گرفته است. بدین‌منظور، نمونه‌های بهسازی نشده و بهسازی شده با گروه ستون سنگی، شامل 7 ستون با قطر 30 میلیمتر و چیدمان مثلثی، در دستگاه برش مستقیم بزرگ‌مقیاس مورد آزمایش قرار گرفته و پارامترهای مقاومت برشی معادل و مقادیر ظرفیت باربری تعیین شده‌اند. آزمایش برش با استفاده از روش سریع انجام شده است. همچنین، تأثیر متغیرهایی چون نوع خاک پیرامونی، تعداد لایه‌های ساخت ستون سنگی و راستای چینش ستون‌های سنگی محدود با چیدمان مثلثی (رأس/ قاعده)، بر پارامترهای مقاومت برشی و ظرفیت باربری مورد ارزیابی قرار گرفته است. بر اساس نتایج حاصل، بهسازی خاک رسی با استفاده از روش گروه ستون سنگی موجب افزایش قابل توجه ظرفیت باربری خاک‌های سست شده است. نتایج آزمایش انجام شده نشان داد کیفیت ستون سنگی اهمیت زیادی در توان باربری آن دارد. علاوه بر این بهسازی خاک رسی CL نسبت به بهسازی خاک CH به روش ستون سنگی می‌تواند توان باربری بستر را بیشتر افزایش دهد که بیانگر کارایی بیشتر این روش بهسازی در خاک های رسی سخت تر است.

کلیدواژه‌ها

بستر رسی؛ ستون سنگی؛ برش مستقیم بزرگ‎مقیاس؛ مقاومت برشی؛ ظرفیت باربری

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