تاثیر شوری بر پتانسیل تورم و انقباض خاک‌های متورم شونده تحت چرخه‌های تر و خشک شدن

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد سازه های آبی

2 عضو هیئت علمی

3 استادیار/ دانشگاه محقق اردبیلی

چکیده

خاک‌های متورم شونده از نوع خاک‌های مشکل‌زایی هستند که با تغییر رطوبت، دچار تغییر حجم میشوند. این خاک‌ها معمولاً حاوی مقادیر زیادی رس بوده و مقدار تورم آن‌ها بستگی کامل به نوع کانی‌های رسی و پیوندهای مولکولی دارد. همچنین نوع مواد شیمیایی که با این نوع خاک تماس پیدا می‌کند بر نحوه رفتار آن بسیار اثر گذار می‌باشد. در این پژوهش اثر شوری بر رفتار خاک‌های رسی تحت چرخه‌های تر و خشک بررسی شد. بدین منظور سه نمونه خاک شامل یک نمونه خاک متورم شونده از اطراف دریاچه ارومیه، در حالت بدون شوری و دو نمونه خاک با شوری 2 و 4 درصد وزنی، با استفاده از نمک NaCl تهیه شده و آزمایش تورم آزاد بر روی نمونه‌ها در دستگاه تحکیم و در معرض چرخه‌های تر و خشک انجام گرفت و در نهایت تأثیر شوری بر رفتار خاک بررسی گردید. همچنین در طی آزمایشها میزان نمک‌زدایی نمونه‌ها مورد بررسی قرار گرفت. نتایج حاصله نشان داد میزان تورم و انقباض در چرخه های دوم از بیشترین مقدار برخوردار بوده است. بررسی چرخه‌ها نشان داد که میزان پتانسیل تورم و انقباض پس از پایان حدود 6 چرخه به مقدار نزدیک به 50 درصد کاهش می‌یابد. همچنین نتایج تحقیق حاضر نشان داد که با افزایش غلظت نمک از میزان تورم نمونه‌ها کاسته شده است. با افزودن میزان اندکی نمک پتانسیل تورمی خاک به میزان قابل توجهی کاهش یافت.

کلیدواژه‌ها

عنوان مقاله [English]

The effect of salinity on the swelling behavior of expansive soils under wetting and drying cycles

نویسنده [English]

  • Hojjat Ahmadi 2
1
2
3
چکیده [English]

Expansive soils is known as a problematic soil that shows volume changes while subjected to moisture content variation. Volume changing of such soils, specially the basis of light structure like base of canals with rigid lining lead to cause high costs. This type of soils evolve more clay and the magnitude of expansion depend upon to the type of minerals and molecular connections. Furthermore the type of chemical materials which is added to the soil, precise an explanatory definition of engineering properties of the soil. In this research the effect of salinity on the behavior of clayey soils under wetting and drying cycle was investigated. In this regards, three expansive soil sample including; zero, two and four weighty percent of NaCl were prepared and free swelling tests under wetting and drying cycles with monitoring of salinity variation were conducted. The results of this investigation revealed that the maximum expansive is refer to the second cycle, as well the expansive behavior after 6 cycle decrease significantly. Also, the achievements of this study confirmed that in the specimens including salt the gravity forces between ions over clays and cation increases and it cause to decrease of swelling. Whereas, in the specimens including 4% salinity the minimum expansive was shown that this may practical as a simple method to control the expansive behavior of clays.

کلیدواژه‌ها [English]

  • Engineering properties
  • free swelling
  • NaCl
  • wetting-drying

مراجع

Aboghobar H. M. 1993. Influence of irrigation water quality on soil infiltration. Irrigation Science, 14(1): 15-19
Ahmadi H., Rahimi H., and Rostami M. 2009. Optimizing the location of contraction-expansion joints in canal lining. Irrigation and Drainage, 58(1): 116-1125.
Asgari F., and Fakher A. 1993. Geotechnical properties of expansive and dispersive soils Tehran University: Jahad Daneshgahi. (In Persian)
Alawaji H. 1999. Swell and compressibility characteristics of sand-bentonite mixtures with liquids, Applied Clay Science 15: 411-430.
Alonso E.E., Romero E., Hoffmann C., and Garcia Escudero E. 2005. Expansive bentonite- sand mixtures in cyclic controlled-suction drying and wetting. Journal of Engineering Geology, 81: 213-226.
Barootkoob S.h., and Rahimi H. 1995. Cracking reasons of concrete lining in Khoozestan province. Msc. Thesis, University of Tehran. (In Persian)
Emdad M. R., Raine S. R., Smith Rod J., and Fardad H. 2004. Effect of water quality on soil structure and infiltration under furrow irrigation. Irrigation Science, 23(2): 55-60.
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.
Chen F.H., and Ma G.S. 1987. Swelling and shrinkage behavior of expansive clays. pp. 127-129. Proceeding of the 6th International Conference on Expansive Soils. New Delhi, India.
Day R.W. 1994. Swell-Shrink Behavior of Compacted Clay. Journal of Geotechnical Engineering, ASCE, 120 (2): 618-623
Dif A.E., and Blumel W.F. 1991. Expansive soils with cyclic drying and wetting. Geotechnical Testing Journal, GTJODJ, 14 (1): 96-102
Estabragh A., R., Parsaei B., and Javadi A.A. 2015. Laboratory investigation of the effect of cyclic wetting and drying on the behaviour of an expansive soil. Soils and Foundations, 55 (2): 304-314
Kalkan, E. 2011. Impact of wetting–drying cycles on swelling behavior of clayey soils modified by silica fume. Applied Clay Science, 52(4), pp.345-352.
Lambe T.W. 1958. The Structure of Compacted Clay.  Journal of the Soil Mechanics and Foundations Division, ASCE, 84: 1-34.
Malik M., Mustafa M.A., and Letey J. 1992. Effect of mixed Na/Ca solutions on Swelling, dispersion and transient water flow in unsaturated montmorillonitic soils. 52: 17-28.
Moghaddas M., Estabragh R. A., and Abdolahi J. 2012. Swell-Shrinkage Paths of a Swelling Soil in Wetting and Drying Cycles with Saline Water. Journal of Water and Soil Science. 22 (3):128-138
Morris P.H., Graham J., and Williams D.J. 1992. Cracking in drying soils. Canadian Geotechnical Journal, 29: 263-277.
Nelson J. D., and Miller D. J. 1992. Expansive Soils: Problems and Practices in Foundation and Pavement Engineering. John Wiley & Sons Inc.
Nowamooz H., and Masroori F. 2010. Influence of suction cycles on the soil fabric of compacted swelling soil. Comptes rendus Geoscience Journal, 342: 901-910.
Oliveria T. S., Costa M. L., and Schaefer C.E. 2005. Water-dispersible clay after wetting and dying cycles in four Brazilian oxisols. Soil and Tillage Research, 83.260-269
Osipov V.I., Bik N.N. and Rumjantseva N.A. 1987. Cyclic swelling of clays applied. Clay Science Journal, Amsterdam, the Netherlands, 2(7), 363-374.
Ring, G.W. 1966. Shrink-Swell Potential of Soils. Highway Research Board. National research council, pp: 1-11.
Rosenbalm D., and Zapata C.E., 2016. Effect of Wetting and Drying Cycles on the Behavior of Compacted Expansive Soils. Journal of Materials in Civil Engineering, 04016191.
Safadoust A., 2016. Effects of the Number of Wetting-Drying Cycles on Structure Stability, Particle Size Distribution and Pore System of Soil. Iranian Journal of Soil and Water Research. 46 (4): 759-767
Salahshour D. F., Davat Gar N., Yazdani, M. R., and Sadraddini A. A. 2016. Effect of increasing salinity of irrigation water on trend of shrinkage cracking development in paddy fields. Iraninan Journal of Soil Research, 30(2), 173-186.
Tang C.S., Shi B., Liu C., Suo W.B. and. Gao L. 2011. Experimental characterization of shrinkage and desiccation cracking in thin clay layer. Applied Clay Science. 52: 69-77
Tawfiq S., and Nabantoglu Z. 2009. Swell-shrink behavior of expansive clays. Proceeding of the 2nd International Conference on Expansive Soil Mechanics and Geotechnical Engineering. Nicosia, North Cyprus. 336-341.
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: 938-959.
Wheeler S.J., Sharma R.S. and Buisson M.S.R. 2003. Coupling of hydraulic hysteresis and stress strain behavior in unsaturated soils. Geotechnique. 53(1): 41-54.
Yazdandoust F., and Yasrobi S.SH. 2010. Effect of cyclic wetting and drying on swelling behavior of polymer-stabilized expansive clays. Applied Clay Science, 50: 461-468
تحقیقات کاربردی خاک
دوره 6، شماره 1
خرداد 1397
صفحه 85-97

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سابقه مقاله

  • تاریخ دریافت: 28 تیر 1395
  • تاریخ بازنگری: 16 بهمن 1395
  • تاریخ پذیرش: 17 اسفند 1395

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