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 *

مراجع

Abdullah, W. S., Alshibli, K. A., and Al-Zou'bi, M. S. (1999). Influence of pore water chemistry on the swelling behavior of compacted clays. Applied Clay Science, 15(5), 447-462.
Al-Homoud, A. S., Basma, A. A., Husein Malkawi, A. I., and Al Bashabsheh, M. A. (1995). Cyclic swelling behavior of clays. Journal of Geotechnical Engineering, 121(7), 562-565.
Alonso, E. E., Romero, E., Hoffmann, C., and García-Escudero, E. (2005). Expansive bentonite–sand mixtures in cyclic controlled-suction drying and wetting. Engineering Geology, 81(3), 213-226.
Barden, L. and Sides, G. R. (1970). Engineering behavior and structure of compacted clay. Journal of Soil Mechanics & Foundations Div., 96(4), 1171-1200.
Basma, A. A., Al-Homoud, A. S., Husein Malkawi, A. I., and Al-Bashabsheh, M. A. (1996). Swelling-shrinkage behavior of natural expansive clays. Applied Clay Science, 11(2), 211-227.
Bolt, G. H. (1956). Physico-chemical analysis of the compressibility of pure clays. Geotechnique, 6(2), 86-93.
Chen, F. H. (1965). The use of piers to prevent uplifting of lightly loaded structures founded on expansive soils. In Proceeding of International Research and Engineering Conference on Expansive Clay Soils, Texas.
Chu, T. Y. and Mou, C. H. (1973). Swelling volume change characteristics of expansive soils determined by controlled suction test. In Proc., of 3rd Int. Conf. on Expansive Soils (Vol. 1, 177-185).
Estabragh, A. R., Moghadas, M., and Javadi, A. A. (2013). Effect of different types of wetting fluids on the behaviour of expansive soil during wetting and drying. Soils and Foundations, 53(5), 617-627.
Gourley, C. S., Newill, D., and Schreiner, H. D. (1993). Expansive soils: TRL’s research strategy. In Proceedings of first international symposium on engineering characteristics of arid soils.
Jones, D. E. and Holtz, W. G. (1973). Expansive soils-the hidden disaster. Civil Engineering 43, 87-89.
Komine, H. and Ogata, N. (1996). Prediction for swelling characteristics of compacted bentonite. Canadian Geotechnical Journal, 33(1), 11-22.
Kröhn, K. P. (2003). New conceptual models for the resaturation of bentonite. Applied clay science, 23(1), 25-33.
Lambe, T. W. (1958). The structure of compacted clay. Journal of the Soil Mechanics and Foundations Division, ASCE, 84, 1-34.
McKeen, R. G. (1992). A model for predicting expansive soil behavior. In Proc., 7th Int. Conf. on Expansive Soils (Vol. 1, 1-6).
Nelson, J. D. and Miller, D. J. (1992). Expansive soils: problems and practices in foundation and pavement engineering. John Wiley & Sons Inc.
Olson, R. E. (1974). Shearing strengths of kaolinite, illite, and montmorillonite. Journal of the Geotechnical Engineering Division, 100(11), 1215-1229.
Osipov, V. I., Bik, N. N., and Rumjantseva, N. A. (1987). Cyclic swelling of clays. Applied clay science, 2(4),363-374.
Parsaee, B. and Estabragh, A. R. (2009). Evaluation of volume change potential in clayey soils during wetting and drying cycles. MSc dissertation, University of Tehran, Karaj. (In Farsi)
Popescu, M. (1980). Behaviour of expansive soils with a crumb structure. In Expansive Soils (158-171). ASCE.
Seed, H. B. and Chan, C. K. (1960). Structure and strength characteristics of compacted clays. Institute of Transportation and Traffic Engineering, University of California.
Siddiqua, S., Blatz, J., and Siemens, G. (2011). Evaluation of the impact of pore fluid chemistry on the hydromechanical behaviour of clay-based sealing materials. Canadian Geotechnical Journal, 48(2), 199-213.
Soltani, A., Estabragh, A. R., Hoorfar, A., and Abdullahi, J. (2014). Effect of initial moisture quality on the mechanical behavior of an expansive soil during wetting and drying. In Proceeding of 8th National conference on Civil Engineering, Babol, Iran.
Subba Rao, K. S. and Satyadas, G. G. (1987). Swelling potential with cycles of swelling and partial shrinkage. In Proceedings, 6th International Conference on Expansive Soils (Vol. 1, 137-142).
Tawfiq, S. and Nalbantoglu, Z. (2009). Swell-Shrink behavior of expansive clays. In Proceeding of 2nd International Conference on New Developments in Soil Mechanics and Geotechnical Engineering, Nicosia, North Cyprus (336-341).
Tripathy, S. and Rao, K. S. S. (2009). Cyclic swell–shrink behaviour of a compacted expansive soil. Geotechnical and Geological Engineering, 27(1), 89-103.
Tripathy, S., Rao, K. S., and Fredlund, D. G. (2002). Water content-void ratio swell-shrink paths of compacted expansive soils. Canadian geotechnical journal, 39(4), 938-959.

فایل ها

هم رسانی

ارجاع به این مقاله

آمار