مطالعه تجربی رفتار کوله‌های خاک مسلح ژئوسنتتیکی تحت اثر شکل بارگذاری

چکیده مقاله :

استفاده از فرآیند مسلح نمودن خاک به‌عنوان روشي جهت برطرف ساختن ضعف مقاومت كششي خاك به كمك اجزاي فلزي يا پليمري با مقاومت كششي مناسب به‌عنوان يكي از روش‌های سريع و اقتصادي پايدارسازي شیروانی‌ها و احداث ديوارهاي حائل شناخته مي‌شود. در این تحقیق با استفاده از مدل‌سازی فیزیکی با شتاب بالا در دستگاه سانتریفیوژ، رفتار کوله‌های خاک مسلح با ارتفاع نسبتاً بلند تحت اثر سربار خارجی مورد ارزیابی قرار گرفت. بدین منظور کوله‌ای به ارتفاع 35 سانتی‌متر معادل 1050 سانتی‌متر در واقعیت با مقیاس 1:30 با استفاده از دستگاه سانتریفیوژ ساخته و تحت بارگذاری در شتاب g30 قرار گرفت. در این تحقیق از خاک دانه‌ای و شش‌لایه مسلح‌کننده ژئوسنتتیکی استفاده گردید. نتایج به‌دست‌آمده نشان داد، ظرفیت باربری پی‌های قرار گرفته بر روی کوله‌های خاک مسلح ارتباط کاملاً مستقیمی با شکل پی داشته و برای پی‌های با عرض یکسان هرچقدر شکل پی از مربع به شکل مستطیلی تغییر یابد (طول پی افزایش یابد) از میزان باربری نهایی کاسته خواهد شد. با بررسی المان‌های مسلح‌کننده خاک در لایه‌های مختلف به لحاظ گسیختگی و افزایش طول مشخص گردید که گسیختگی و افزایش برای پی نواری بیشترین مقدار و در پی مربعی کمترین مقدار است. به بیان دیگر با افزایش سطح بارگذاری عمق تأثیر تنش بیشتر شده و لایه‌های مسلح‌کننده بیشتری در عمق تحت‌تأثیر بارگذاری قرار خواهند گرفت

چکیده انگلیسی :

Using the reinforced soil method as a method to overcome the weak tensile strength of the soil with the help of metal or polymeric components with appropriate tensile strength is known as one of the fast and economical methods of stabilizing the slopes and building retaining walls. In this research, using physical modeling with high acceleration in a centrifuge, the behavior of reinforced soil abutments with a relatively high height under the effect of external overhead was evaluated. For this purpose, a reinforced soil slope with a height of 35 cm, equivalent to 1050 cm, was made in reality with a scale of 1:30 using a centrifuge and was subjected to loading at an acceleration of 30g. In the construction of reinforced soil walls, sandy soil and 6 layers of geosynthetic reinforcement with a thickness of 0.25 cm were used. The obtained results showed that the bearing capacity of foundations placed on reinforced soil abutments  has a direct relationship with the shape of the foundation, and for foundations with the same width, the more the shape of the foundation changes from square to rectangular (the length of the foundation increases), the greater the bearing capacity. The final will be reduced. By examining soil reinforcement elements in different layers in terms of rupture and length increase, it was found that the rupture and increase is the highest for strip foundation and the lowest for square foundation. In other words, with an increase in the depth of the loading level, the impact of stress will increase and more reinforcing layers in depth will be affected by the loading

منابع و مأخذ:

[1] J. JONES, Guide to Reinforced Fill Structure And Slope Design, 2002.
[2] B.R. Christopher, V. Elias, Mechanically Stabilized Earth Walls and Reinforced Soil Slopes Design and Construction Guidelines, United States. Federal Highway Administration, 1997.
[3] N. Abu-Hejleh, J. Zornberg, T. Wang, J. Watcharamonthein, Monitored displacements of unique geosynthetic-reinforced soil bridge abutments, Geosynthetics International 9(1) (2002) 71-95.
[4] H.I. Ling, Y. Mohri, D. Leshchinsky, C. Burke, K. Matsushima, H. Liu, Large-scale shaking table tests on modular-block reinforced soil retaining walls, Journal of Geotechnical and Geoenvironmental engineering 131(4) (2005) 465-476.
[5] A. Murali Krishna, A. Bhattacharjee, Seismic analysis of reinforced soil retaining walls, Geotechnical Design and Practice: Selected Topics (2019) 159-171.
[6] D. Raisinghani, B. Viswanadham, Centrifuge model study on low permeable slope reinforced by hybrid geosynthetics, Geotextiles and Geomembranes 29(6) (2011) 567-580.
[7] C. Yoo, S.-B. Kim, Performance of a two-tier geosynthetic reinforced segmental retaining wall under a surcharge load: full-scale load test and 3D finite element analysis, Geotextiles and Geomembranes 26(6) (2008) 460-472.
[8] W. Burwash, J. Frost, Case history of a 9 m high geogrid reinforced retaining wall backfilled with cohesive soil, Geosynthetics, Conference, 1991, Atlanta, Georgia, USA, 1991.
[9] R. Fannin, S. Hermann, Performance data for a sloped reinforced soil wall, Canadian Geotechnical Journal 27(5) (1990) 676-686.
[10] K. Yang, J. Zornberg, C. Liu, H. Lin, Stress distribution and development within geosynthetic-reinforced soil slopes, Geosynthetics International 19(1) (2012) 62-78.
[11] K.-h. Yang, Stress distribution within geosynthetic-reinforced soil structures, The University of Texas at Austin2009.
[12] E. Haza, P. Gotteland, J.-P. Gourc, Design method for local load on a geosynthetic reinforced soil structure, Geotechnical & Geological Engineering 18(4) (2000) 243-267.
[13] L. Wichter, P. Risseeuw, G. Gay, Large scale test on bearing behaviour of a woven reinforced earth, Proceeding of the 3rd International Conference on Geotextiles, Vienna, Austria, 1986, pp. 1073-1078.
[14] B. Thamm, B. Krieger, J. Krieger, Full scale test on a geotextile reinforced retaining structure: Proc 4th International Conference on Geotextiles, Geomembranes and Related Products, The Hague, 28 May–1 June 1990 V1 P3–8. Publ Rotterdam: AA Balkema, 1990, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Pergamon, 1991, p. A384.
[15] R. Bathurst, D. Walters, N. Vlachopoulos, P. Burgess, T. Allen, Full scale testing of geosynthetic reinforced walls, Advances in transportation and geoenvironmental systems using geosynthetics2000, pp. 201-217.
[16] J. Mitchell, M. Jaber, C. Shen, Z. Hua, Behavior of reinforced soil walls in centrifuge model tests, In: Proceedings of Centrifuge '88, Paris, France, 1988, pp. 259-271.
[17] D. Goodings, J. Santamarina, Reinforced earth and adjacent soils: centrifuge modeling study, Journal of geotechnical engineering 115(7) (1989) 1021-1025.
[18] A. Porbaha, D. Goodings, Geotextile reinforced cohesive slopes on weak foundations, Proceedings of Centrifuge, 1994, pp. 623-628.
[19] E. Guler, C. Ocbe, Centrifuge and full scale models of geotextile reinforced walls and several case studies of segmental retaining walls in Turkey, Emirates J Eng Res 8(1) (2003) 15-23.
[20] J.G. Zornberg, Performance of geotextile-reinforced soil structures, University of California, Berkeley, 1994.
[21] F. Arriaga, Responses of geosynthetic-reinforced structures under working stress and failure conditions, University of Colorado at Boulder, 2004.
[22] A. Sommers, B. Viswanadham, Centrifuge model tests on the behavior of strip footing on geotextile-reinforced slopes, Geotextiles and Geomembranes 27(6) (2009) 497-505.
[23] P. Aklil, W. Wu, Centrifuge model tests on foundation on geosynthetic reinforced slope [D], Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013 (2013).
[24] D.M. Wood, Geotechnical modelling, CRC press2014.
[25] L. Fuglsang, The application of the theory of modelling to centrifuge studies, Centrifuge in soil mechanics (1988).
[26] E. Shin, B. Das, Experimental study of bearing capacity of a strip foundation on geogrid-reinforced sand, Geosynthetics International 7(1) (2000) 59-71.
[27] TSR101, General technical specifications of the road 101, Geosynthetics in road construction, Plan and Budget organization, president of the Islamic Republic of Iran, Tehran, IRAN, 2013.
[28] J.G. Zornberg, N. Sitar, J.K. Mitchell, Performance of geosynthetic reinforced slopes at failure, Journal of Geotechnical and Geoenvironmental Engineering 124(8) (1998) 670-683.
[29] ASTM.D4595, Standard Test Method for Tensile Properties of Geotextiles by the Wide-Width Strip Method, ASTM (2017).
[30] T. Pham, S.M. Rahmaninezhad, A. Palma, T. Phan, T. Vu, Analytical Method for Predicting Lateral Facing Deflection of Geosynthetic-Reinforced Soil Abutment Walls, Geo-Congress 2023, 2023, pp. 345-358.
[31] A.B. Cerato, A.J. Lutenegger, Scale effects of shallow foundation bearing capacity on granular material, Journal of Geotechnical and Geoenvironmental Engineering 133(10) (2007) 1192-1202.
[32] D. Leshchinsky, G.F. Marcozzi, Bearing capacity of shallow foundations: rigid versus flexible models, Journal of Geotechnical Engineering 116(11) (1990) 1750-1756.