معرفی تکنیکی جدید برای ارزیابی رفتار و تغییرحجم خاک‌های غیراشباع

مهندسی عمران فردوسی

مقاله 3، دوره 25، شماره 2، آبان 1393، صفحه 31-52   

نوع مقاله: پژوهشی

شناسه دیجیتال (DOI): 10.22067/civil.v25i2.40700

نویسندگان

غلام حسن اسکندری^{* 1}؛ علی رئیسی استبرق¹؛ عباس سروش²

¹دانشگاه تهران

²دانشگاه صنعتی امیرکبیر

چکیده

تعیین تغییرحجم خاک‌های غیراشباع در حین بارگذاری و تغییرمکش از مشکلات اساسی آزمایشگاهی برای این نوع خاک‌ها محسوب می‌گردد. بررسی منابع نشان می‌دهد تاکنون تلاش‌های بسیاری برای ابداع ابزار آزمایشگاهی مناسب به‌منظور اندازه‌گیری تغییرحجم نمونه‌های غیراشباع خاک با دقت مناسب صورت گرفته است. این مقاله به شرح جزئیات و مزایای طراحی و ساخت یک دستگاه سه‌محوری با سلول دوگانه‌ی کاملاً خودکار برای اندازه‌گیری تغییرحجم نمونه‌های غیراشباع خواهد پرداخت. در ادامه، مراحل کالیبراسیون برای تغییرحجم ظاهری ناشی از انبساط اولیه و جذب آب و انبساط اتصالات مربوطه‌ی دستگاه مذکور نیز ارائه شده است. آزمایش بر روی نمونه‌های غیراشباع خاک متورم‌شوندهبرای تعیین منحنی مشخصه‌ی آب‌خاک در شرایط غیرایزوتروپیک انجام شد. نتیجه‌های به‌دست آمده نشان‌دهنده‌ی عملکرد مناسب دستگاه ساخته شده می‌باشد.هم‌چنین نتایج آزمایش‌ها نشان می‌دهد که منحنی مشخصه‌ی رطوبتی خاک تابعی از اعمال بار وارد به نمونه می‌باشد.

کلیدواژه‌ها

خاک غیراشباع؛ تغییرحجم؛ سلول دوگانه؛ کالیبراسیون؛ منحنی مشخصه‌ی رطوبتی خاک؛ بارگذاری غیرایزوتروپیک

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