بررسی اثر کیفیت شیمیایی رطوبت اولیه بر خواص مکانیکی یک خاک متورم شونده در چرخه‏ های تر و خشک

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد سازه‏ های آبی گروه مهندسی آبیاری و آبادانی دانشگاه تهران

2 دانشیار گروه مهندسی آبیاری و آبادانی دانشگاه تهران

3 مربی گروه مهندسی آبیاری و آبادانی دانشگاه تهران

چکیده

خاک‏های متورم‌شونده از خاک‏های مشکل‌آفرین در پروژه‏های عمرانی محسوب می‏شوند. این دسته خاک‏ها با جذب آب متورم و با ازدست‌دادن آن منقبض می‏شوند. پدیدة تر و خشک شدن این خاک‏ها را اصطلاحاً چرخه‏های تر و خشک می‌نامند. در این پژوهش تأثیر کیفیت شیمیایی آب منفذی بر پتانسیل تورمی و انقباضی یک خاک متورم‌شونده بررسی شد. سی و سه نمونة‏ آزمایشگاهی با آب مقطر، محلول سدیم‏ کلرید (با غلظت 50 گرم بر لیتر)، و کلسیم کلرید (با غلظت 250 گرم بر لیتر) به روش استاتیکی تهیه شد. آزمایش‏ها در یک دستگاه تحکیم اصلاح‌شده، تحت سر بار 10 کیلوپاسکال، صورت پذیرفت و هنگام اعمال چرخة تر استغراق نمونه‏ها به وسیلة آب مقطر انجام شد. نتایج نشان داد پتانسیل تورمی نمونة‏ تهیه‌شده با محلول کلسیم کلرید بیشتر از نمونه‏های تهیه‌شده با آب مقطر و محلول سدیم کلرید است و مقدار پتانسیل تورمی و انقباضی در این نمونه‏ها بعد از گذشت تقریباً پنج چرخه برای آب مقطر و سدیم کلرید و سه چرخه برای کلسیم کلرید به حالت تعادل می‏رسد. از سویی نتایج اندازه‏گیری تغییرات حجم ویژه و وزن واحد حجم خشک نمونه‏های مختلف با آب منفذی متفاوت نشان داد مقادیر آن‏ها نیز با افزایش چرخه‏های متوالی تر و خشک به مقدار نسبتاً ثابتی می‏رسد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of Pore Water Quality on the Mechanical Behavior of an Expansive Soil during Wetting and Drying Cycles

نویسندگان [English]

  • Amin Soltani 1
  • Ali Raeesi Estabragh 2
  • Jamal Abdollahi 3
1 M.Sc. Student, Irrigation and Reclamation Eng. Dept., University of Tehran
2 Associate Prof., Irrigation and Reclamation Eng. Dept., University of Tehran
3 Instructor, Irrigation and Reclamation Eng. Dept., University of Tehran
چکیده [English]

Expansive soils are considered a worldwide problem as they cause extensive damage to
civil engineering structures. An important characteristic of expansive soils is their
susceptibility to volume change due to the phenomenon of wetting and drying. This paper
presets the effect of pore water quality on the swelling and shrinkage behavior of an
expansive soil during wetting and drying cycles. Thirty three soil samples were prepared
through static compaction with various pore water qualities consisting of distilled water,
sodium chloride (50g/lit) and calcium chloride (250gr/lit). Wetting and drying cycles
were conducted on samples in a modified odometer apparatus under the surcharge
pressure of 10 kPa using distilled water as the reservoir fluid during the process of
wetting. Results indicated that samples prepared with calcium chloride show more
swelling potential as compared with distilled water and sodium chloride. Furthermore,
swelling and shrinkage potential, specific volume and dry unit weight for soil samples
reach equilibrium after 5 cycles for distilled water and sodium chloride and while 3
cycles for calcium chloride.

کلیدواژه‌ها [English]

  • pore water
  • Swelling and shrinkage potential
  • Specific volume
  • Dry unit weight *
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