اثر دما بر ضریب نفوذپذیری خاک رسی متراکم و عایق رسی ژئوسینتتیک (GCL)

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

گروه مهندسی عمران، دانشکده فنی، دانشگاه ارومیه

چکیده

تأثیر دما در خواص نفوذپذیری خاک­ های رسی متراکم یکی از پارامترهای اساسی در طراحی لایه­ های عایق مهندسی است که در معرض شیرابه ­ها هستند. در این تحقیق اثر دما بر ضریب نفوذپذیری رس متراکم منطقه نازلوی ارومیه و عایق ­های رسی ژئوسینتتیک (Geosynthetic) و همچنین تأثیر میزان تنش مؤثر و دانسیته بر نرخ تغییر ضریب نفوذپذیری نمونه ­های رسی بررسی شده است. دستگاه تعیین ضریب نفوذپذیری سه­ محوری با دیواره انعطاف­ پذیر برای اندازه ­گیری ضریب نفوذپذیری نمونه ­ها تحت تأثیر دما مورداستفاده قرار گرفته است. با افزایش دما ویسکوزیته (Viscosity) محلول کاهش یافته و اثرات دمایی ساختار خاک را تغییر می­ دهد و تولید حفرات بزرگ­تر بین ذرات رس می­کند و باعث ایجاد تغییر در سطح مقطع مؤثر جریان شده و آب جذب‌شده تبدیل به آب آزاد می­ شود و در نتیجه باعث افزایش ضریب نفوذپذیری خاک رسی می­ شود. با افزایش دما از 23 به 50 درجه سانتی­گراد ضریب نفوذپذیری خاک رسی تقریباً 3/2 برابر می­ شود. افزایش تنش مؤثر از kPa30 به kPa65 باعث می­ شود ضریب نفوذپذیری نمونه­ های رسی، تقریباً به‌اندازه 4/0 نمونه­ هایی شود که تحت تنش مؤثر kPa30 قرار داشتند. با کاهش دانسیته خاک رسی از 9/1 گرم بر سانتی­متر مکعب به 5/1 گرم بر سانتی­متر مکعب بسته به­ میزان دمای آزمایش، ضریب نفوذپذیری 2 تا 3 برابر می ­شود. برخلاف خاک ­های رسی، در عایق ­های رسی ژئوسینتتیک افزایش دما تأثیر اندکی (در حدود 20%) در ضریب نفوذپذیری این لایه ­ها داشته و زمانی که این لایه ­ها در معرض افزایش دما قرار گیرند به عملکرد خوب خود به‌عنوان یک مانع هیدرولیکی ادامه می­ دهند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of Temperature on the Hydraulic Conductivity of Compacted Clayey Soil and Geosynthetic Clay Liner (GCL)

نویسندگان [English]

  • Mehdi Gholikhany
  • Kazem Badv
Department of Civil Engineering, Urmia University, Urmia, Iran
چکیده [English]

In most studies, the increase in hydraulic conductivity with temperature has been considered due to the decrease in the viscosity of fluid (Habibagahi, 1977; Cho et al., 1999; Delage et al., 2011). However, the changes in hydraulic conductivity with temperature are not only influenced by the changes in water properties, but also by the thermal effect on soil-water interaction at the microstructure level (Towhata et al., 1993; Romero et al., 2001; Villar and Lloret, 2004). In the present study, results of temperature effects on the hydraulic conductivity of compacted clay from the Nazlou region of Urmia City (Iran), and geosynthetic clay liner (GCL) are presented. In this research, experiments were conducted by flexible-wall triaxial permeability apparatus. In order to increase the temperature of the permeability cell to a desired level, a heater and a temperature sensor were used. Results showed that by increasing the temperature, the viscosity of fluid decreases, the soil pore size increases, cross-section of effective flow increases and hence, the soil hydraulic conductivity increases. Increasing the effective stress causes the rate of increase in soil permeability due to temperature to decrease. Results showed that temperature increase does not have a significant effect on the hydraulic conductivity increase of geosynthetic clay liners.

کلیدواژه‌ها [English]

  • Hydraulic Conductivity
  • Temperature
  • Compacted clay
  • GCL
  • Effective stress
  • Density
Ai H, Young JF, Scherer GW, “Thermal expansion kinetics: method to measure permeability of cementitious materials: II, application to hardened cement paste”, Journal of the American Ceramic Society, 2004, 84 (2), 385-391.
ASTM D5084, “Standard test method for measurement of hydraulic conductivity of saturated porous materials using a flexible wall permeameter”, ASTM D5084-16a, 2016.
Badv K, Omidi A, “Effect of synthetic leachate on the hydraulic conductivity of clayey soil in Urmia City landfill site”, Iranian Journal of Science & Technology, Transaction B, Engineering, 2007, 31, B5, 535-545.
Bastiaens W, Bernier F, Li XL, “Experiments and conclusions on fracturing, self-healing and self-sealing processes in clays”, Journal of Physics and Chemistry of the Earth, 2007, 32, 600-615
Benson CH, Gribb MM, “Measuring unsaturated hydraulic conductivity in the laboratory and field In Unsaturated Soil Engineering Practice”, American Society of Civil Engineers (ASCE), 1997, Reston, Va. 113-168.
Blümling P, Bernier F, Lebon P, Martin CD, “The excavation damaged zone in clay formations time-dependent behaviour and influence on performance assessment”, Journal of Physics and Chemistry of the Earth, 2007, 32, 588-599.
Chen GJ, Maes T, Vandervoort F, Sillen X, Van Marcke P, Honty M, Vanderniepen P, “Thermal impact on damaged Boom Clay and opalinusclay: permeameterand isostatic tests with mCT scanning”, Rock Mechanics and Rock Engineering 2014, 47 (1), 87e99.
Chen WZ, Ma YS, Sillen X, “Effect of temperature and thermally-induced microstructure change on hydraulic conductivity of Boom Clay”, Journal of Rock Mechanics and Geotechnical Engineering, 2017, 383-395.
Cho Wj, Lee Jo, Chun Ks, “The temperature effects on hydraulic conductivity of compacted bentonite”, Applied Clay Science, 1999, 14 (1), 47-58.
Daniel DE, “Measurement of hydraulic conductivity of unsaturated soils with thermocouple psychrometers”, Soil Science Society of America Journal, 1982, 20 (6), 1125-1129.
Delage P, Sultan N, Cui YJ, Ling LX, “Permeability change in Boom Clay with temperature”, arXiv preprint arXiv, 2011, 1112. 6396.
Gao HB, Shao MA, “Effect of temperature changes on soil hydraulic properties”, Soil Tillage Res, 2015, 153, 145-154.
Ghabezloo S, Sulem J, Saint-Marc J, “Evaluation of a permeability-porosity relationship in a low permeability creeping material using a single transient test”, International Journal of Rock Mechanics and Mining Sciences, 2009, 46 (4), 761-768.
Habibagahi K, “Temperature effect and the concept of effective void ratio”, Indian Geotechnical Journal 1977, 7 (1), 14-34.
Hopmans JW, Dane JH, “Temperature dependence of soil hydraulic properties”, Soil Science Society of America, 1986, 50, 4-9.
Jobmann M, Polster M, “The response of Opalinus claystone due to heating: a combined analysis of in situ measurement, laboratory investigations and numerical calculations”, Phys Chem Earth, 2007, 32 (8-14), 929-936.
Li XL, Bastiaens W, Van Marcke P, Verstricht J, Chen GJ, Weetjens E, Sillen X, “Design and development of large-scale in situ PRACLAY heater test and horizontal high-level radioactive waste disposal gallery seal test in Belgian HADES”, Journal of Rock Mechanics and Geotechnical Engineering, 2010, 2 (2), 103e 10.
Liu MX, Cui WH, Wu D, Liao LJ, Du WZ, “Soil macropore structures and their effect on preferential flow”, Applied Mechanics, 522, 990-994.
Lima A, “Ther        mo-hydro-mechanical behaviour of two deep Belgian clay formations, Boom and Ypresian Clays”, PhD Thesis, 2011, Barcelona, Spain: universitat politecnica de catalunya.
Lu Y, “Temperature effect on unsaturated hydraulic properties of two fine-grained soils and its influence on moisture movement under an airfield test facility”, Master of science Thesis, 2015, Arizona State University.
Monfared M, Sulem J, Delage P, Mohajerani M, “On the THM behaviour of a sheared Boom clay sample: application on the behaviour and sealing properties of the EDZ”, Engineering Geology, 2012, 124, 47-58.
Pusch R, Guven N, “Electron microscopic examination of hydrothermally treated bentonite clay”, Engineering Geology, 1990, 28 (3), 303-14.
Ren J, Shen Zh, Yang J, Zhao J, Yin J, “Effect of temperature and dry density on hydraulic conductivity of silty clay under infiltration of low-temperature water”, Arabian Journal for Science and Engineering, 2013.
Romero E, Gens A, Lloret A, “Temperature effects on the hydraulic behavior of an unsaturated clay”, Geotechnical & Geological Engineering, 2001, 19 (3-4), 311-32.
Rowe RK, Caers CJ, Reynolds G, Chan C, “Design and construction of barrier system for the Halton Landfill”, Canadian Geotechnical Journal, 2000, 37 (3), 662-675.
Schneider M, Goss KU, “Temperature dependence of the water retention curve for dry soils”, Water Resources, 2011, 47, 5.
Towhata I, Kuntiwattanakul P, Seko I, Ohishi K, “Volume change of clays induced by heating as observed in consolidation tests”, Soils and Foundations, 1993, 33 (4), 170-83.
Villar MV, Lloret A, “Influence of temperature on the hydro-mechanical behavior of a compacted bentonite”, Applied Clay Science, 2004, 26 (1), 337-50.
Wan M, “Study of soil-water characteristics and hydraulic conductivity of highly compacted GMZ bentonite under temperature control”, Ph.D. Thesis, 2010, Shanghai, China, Tongji University.
Wan M, Ye WM, Chen YG, Cui YJ, Wang J, “Influence of temperature on the water retention properties of compacted GMZ01 bentonite”, Environmental Earth Sciences, 2015, 73 (8), 4053-4061.
Qiao X, Ma Sh, Pan G, Liu G, “Effects of temperature change on the soil water characteristic curve and a prediction model for the mu us bottomland, northern china”, 2019, Water, 11, 1235.