بررسی اثر زبری بر رفتارهای مقاومتی و تغییر‌حجمی سطح مشترک ماسه و فولاد

نوع مقاله: مقاله پژوهشی

نویسندگان

گروه آموزشی ژئوتکنیک، دانشکده مهندسی عمران و محیط زیست، دانشگاه صنعتی شیراز، شیراز، ایران

چکیده

ظرفیت باربری پوسته شمع‌ها و همچنین پایداری دیوارهای نگهبان و سازه‌های خاک مسلح به رفتار سطح مشترک خاک-سازه وابسته است. با انجام آزمایش‌های برش مستقیم، رفتار یک ماسه ریزدانه تیزگوشه در این تحقیق بررسی شد. سپس با ساخت صفحات فولادی با زبری‌های سطحی مختلف و قرار دادن آنها در نیمه پایینی جعبه برش مستقیم، رفتار‌ سطح مشترک این صفحه‌ها با نمونه‌های متراکم و شل ماسه بررسی گردید. آزمایش­ها نشان می­دهد که مقاومت برشی و گرایش به اتساع سطح مشترک ماسه و فولاد همواره کمتر از مقادیر متناظر به دست آمده برای نمونه‌های ماسه است. در این خصوص، زاویه اصطکاک داخلی اوج برای سطح مشترک فولاد زبر با ماسه متراکم و شل به ترتیب در حدود 40 و 25 درصد کمتر از مقادیر متناظر برای ماسه متراکم است. به طور مشابه، زاویه اصطکاک داخلی اوج برای سطح مشترک فولاد با زبری میانه و ماسه متراکم و شل به ترتیب در حدود 60 و 45 درصد کمتر از مقادیر متناظر برای ماسه شل است.  

کلیدواژه‌ها


عنوان مقاله [English]

Study on the Influence of Roughness on the Strength and Volume Change Behaviors of Sand-Steel Interfaces

نویسندگان [English]

  • Benyamin Farhadi
  • Ali Lashkari
Geotechnical Department, Faculty of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran
چکیده [English]

The bearing capacity of piles shaft and stability of retaining walls and reinforced soil structures depend on the behavior of soil-structure interfaces. Using direct shear apparatus, behavior of a sand with fine angular grains was studied. Steel plates with two surface roughness values were separately embedded at the lower half of the shear box and consequently, the upper half was filled with dense or loose sand. Then, the behavior of interfaces forming between dense/loose sand and rough/medium rough steel plates was studied. Tests show that the shear strength and dilation in sand-structure interfaces are significantly less than the corresponding values for sand. In this regard, the peak friction angle of rough steel plate in contact with dense and loose samples is, respectively, about 40 and 25 percent less than those of dense and loose sand. In a similar fashion, the peak friction angle of medium rough steel plate in contact with dense and loose samples is about 60 and 45 percent less than those in dense and loose sand, respectively.

کلیدواژه‌ها [English]

  • Soil-Structure Interface
  • Roughness
  • Shear strength
  • Dilation
  • Direct Shear Test
[1]     DeJong, J. T. & Westgate, Z. J. Role of initial state, material properties, and confinement condition on local and global soil-structure interface behavior. ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol. 135, No. 1, pp. 1646-1660, 2009.
[2]     DeJong, J. T., White, D. J., & Randolph, M. F. Microscale observation and modeling of soil-structure interface using particle image velocimetry. Soils and Foundations. Vol. 46, No. 1, pp. 15-28, 2006.
[3]     Porcino, D., Fioravanye, V., Ghionna, V. N., & Pedroni, S. Interface behavior of sands from constant normal stiffness direct shear tests. ASTM Geotechnical Testing Journal. Vol. 26, No. 3, pp. 1-13, 2003.
[4]     Fioravante, V. On the shaft friction modeling of non-displacement piles in sand. Soils and Foundations, Vol. 42, No. 2, pp. 23-33, 2002.
[5]     Miller, G. A. & Hamid, T. B. Interface direct shear testing of unsaturated soil. ASTM Geotechnical Testing Journal. Vol. 30, No. 3, pp. 182-191, 2007.
[6]     Hu, L. & Pu, J. Testing and modeling of soil-structure interface. ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol. 130, No. 8, pp. 851-860, 2004.
[7]     Lings, M. L. & Dietz, M. S. The peak strength of sand-steel interfaces and the role of dilation. Soils and Foundations, Vol. 45, No. 6, pp. 1-14, 2005.
[8]     Kishida, H. & Uesugi, M. Tests of interfaces between sand and steel in simple shear apparatus. Géotechnique, Vol. 37, No. 1, pp. 45-52, 1987.
[9]     Uesugi, M. & Kishida, H. Frictional resistance at yield between dry and mild steel. Soils and Foundations. Vol. 26, No. 4, pp. 139-149, 1986.
[10]  Evgin, E. & Fakharian, K. Effect of stress path on the behavior of sand-steel interface. Canadian Geotechnical Journal, Vol. 33, pp. 853-865, 1996.
[11]  Fakharian, K. & Evgin, E. Cyclic simple shear behavior of sand-steel interfaces under constant normal stiffness condition. ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol. 123, No. 12, pp. 1098-1105, 1997.  
[12]  Lehan, B. M., Jardine, R. J., Bond, A. J., & Frank, R. Mechanisms of shaft friction in sand from instrumented pile tests. ASCE Journal of Geotechnical Engineering, Vol. 119, No. 1, pp. 19-35, 1993.
[13]  Krabbenhoft, S., Andersen, A., & Damkilde, L. The tensile capacity of bored piles in frictional soils. Canadian Geotechnical Journal, Vol. 45, pp. 1715-1722, 2008
[14]  Rollins, K. M., Clayton, R. J., Mikesell, R. C., & Blaise, B. C. Drilled shaft side friction in gravelly soils. ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol. 131, No. 8, pp. 987-1003, 2005
[15]  Tabucanon, J. T., Airey, D. W., & Poulos, H. G. Pile skin friction in sands from constant normal stiffness tests. ASTM Geotechnical Testing Journal, Vol. 18, No. 3, pp. 350-364, 1995
[16]  Lehan, B. M., Gaudin, C. & Schneider, J. A. Scale effect on tension capacity for rough piles buried in dense sand. Géotechnique, Vol. 55, No. 10, pp. 709-719, 2005.
[17]  Liu, H., Song, E., & Ling, H. I. Constitutive modeling of soil-structure interface through the concept of critical state soil mechanics. Mechanics Research Communications, Vol. 33, pp. 515-531. 2006
[18]  Lashkari, A. Prediction of the shaft resistance of nondisplacement piles in sand. International Journal for Numerical and Analytical Methods in Geomechanics. Vol. 37, pp. 904-931, 2013.
[19]  Lashkari, A. A critical state model for saturated and unsaturated interfaces. Scientia Iranica, Vol. 19, No. 5, pp. 1147-1156. 2012.