مطالعه عددی آزمایش نفوذ پیزوکن در خاک‌ ماسه‌ای فیروزکوه با شرایط زهکشی مختلف

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران

چکیده

آزمایش نفوذ پیزوکن یکی از رایج­ترین آزمایش ­های میدانی است که از آن، به ­منظور اندازه ­گیری فشار آب منفذی، شناسایی لایه ­بندی خاک و تخمین پارامترهای ژئوتکنیکی زمین استفاده می­ شود. بسته به نوع خاک که در محدوده رس تا ماسه قرار گرفته، شرایط زهکشی ­شده، زهکشی ­نشده و یا زهکشی جزئی می تواند در حین فرایند نفوذ رخ دهد. در خاک­ های لای‌دار و ترکیب رس- ماسه، وجود شرایط زهکشی جزئی در آزمون پیزوکن محتمل است، که اغلب در تفسیرهای آزمایش، از این موضوع صرف­نظر می ­شود. در ادبیات فنی، بررسی تأثیر شرایط زهکشی بر نتایج آزمایش پیزوکن عمدتاً به ­صورت آزمایشگاهی یافت می‌شود، و مطالعات عددی که بتواند مدل­سازی قابل قبولی از پیچیدگی های این آزمون مانند اندرکنش خاک-مخروط، اندرکنش آب-خاک، تغییر شکل­ های بزرگ و اثر رفتار غیرخطی خاک را ارائه دهد، به­ ندرت انجام شده است. در این مقاله، به­ کمک نرم ­افزار المان محدود آباکوس و با استفاده از مدل رفتاری پیشرفته هایپوپلاستیک تغییر شکل­ های بزرگ و رفتار غیرخطی خاک در حین فرآیند نفوذ مدل­سازی و رفتار خاک ماسه­ ی اشباع فیروزکوه در شرایط زهکشی و درصد تراکم ­های مختلف تحلیل شد. سپس با استفاده از نتایج به ­دست آمده، محدوده تأثیر نفوذ مخروط بر خاک اطراف و محدوده شرایط زهکشی جزئی برای خاک ماسه ­ای فیروزکوه بررسی شد. همچنین نشان داده شد که شرایط زهکشی و درصد تراکم خاک تأثیر قابل ملاحظه ­ای بر روند تغییرات اضافه فشار آب منفذی در خاک اطراف مخروط دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

A numerical study of piezocone test in Firoozkooh sandy soil under different drained conditions

نویسندگان [English]

  • Mohammad Javad Mashin chian
  • mohammad mehdi ahmadi
Ph.D Candidate in Geotechnical Engineering, Faculty of Civil Engineering, Sharif University of Technology, Tehran, Iran.
چکیده [English]

The piezocone penetration test is commonly used to measure pore water pressure, identify soil profiles and estimate their material properties. Depending on the soil type, ranging from clay to sand, undrained, partially drained, or drained conditions may occur during cone penetration. In silt and sand–clay mixtures, the piezocone penetration is characterized by partially drained conditions, which are often neglected in data interpretation. The effect of drainage on piezocone measurements has been mainly studied experimentally. Numerical analyses are rare because taking into account large soil deformations, soil–water and soil–structure interactions, and nonlinear soil behavior are still challenging tasks. In this paper, using an advanced hypoplastic constitutive model and ABAQUS finite element software, large deformations and nonlinear behavior of soil during penetration were modeled, and the behavior of Firoozkooh saturated sandy soil having different drainage conditions and relative densities were analyzed. Then, using the obtained results, the range of influence of cone penetration on the surrounding soil and the range of partial drainage conditions for Firoozkooh sandy soil were investigated. It was also shown that drainage condition and density of the soil had a significant effect on the affected soil area and the trend of changes in excess pore water pressure.

کلیدواژه‌ها [English]

  • Piezocone Test
  • Partial Drainage
  • Numerical Modeling
  • ABAQUS Software
  • Hypoplastic constitutive model
[1] Golestani Dariani AA, Ahmadi MM. Generation and Dissipation of Excess Pore Water Pressure During CPTu in Clayey Soils: A Numerical Approach. Geotechnical and Geological Engineering. 2021 Jun;39(5):3639-53.
[2] Ceccato, Francesca, Lars Beuth, and Paolo Simonini, Analysis of piezocone penetration under different Drainage conditions with the two-phase material point method, Journal of Geotechnical and Geoenvironmental Engineering 142.12 (2016): 04016066.
[3] M. Randolph, S. Hope, Effect of cone velocity on cone resistance and excess pore pressures, in:  Effect of cone velocity on cone resistance and excess pore pressures, Yodogawa Kogisha Co. Ltd, 2004, pp. 147-152.
[4] K. Kim, M. Prezzi, R. Salgado, W. Lee, Effect of penetration rate on cone penetration resistance in saturated clayey soils, Journal of Geotechnical and Geoenvironmental Engineering, 134(8) (2008) 1142-1153.
[5] E. Susila, R.D. Hryciw, Large displacement FEM modelling of the cone penetration test (CPT) in normally  consolidated sand, International Journal for Numerical and Analytical methods in Geomechanics, 27(7) (2003) 585-602.
[6] W. Huang, D. Sheng, S. Sloan, H. Yu, Finite element analysis of cone penetration in cohesionless soil, Computers and Geotechnics, 31(7) (2004) 517-528.
[7] G.P. Kouretzis, D. Sheng, D. Wang, Numerical simulation of cone penetration testing using a new critical state constitutive model for sand, Computers and Geotechnics, 56 (2014) 50-60.
[8] M. Abu-Farsakh, M. Tumay, G. Voyiadjis, Numerical parametric study of piezocone penetration test in clays, International Journal of Geomechanics, 3(2) (2003) 170-181.
[9] L. Beuth, P. Vermeer, Large deformation analysis of cone penetration testing in undrained clay, Installation effects in geotechnical engineering, (2013).
[10] M.F. Silva, D.J. White, M.D. Bolton, An analytical study of the effect of penetration rate on piezocone tests in clay, International Journal for Numerical and Analytical methods in Geomechanics, 30(6) (2006)501-527.
[11] J. Yi, S. Goh, F. Lee, M. Randolph, A numerical study of cone penetration in fine-grained soils allowing for consolidation effects, Géotechnique, 62(8) (2012) 707-719.
[12] Mo, P. Q., Gao, X. W., Yang, W., & Yu, H. S., A cavity expansion–based solution for interpretation of CPTu data in soils under partially drained conditions, International Journal for Numerical and Analytical Methods in Geomechanics, 44(7) (2020) 1053-1076.
[13] C. Teh, G. Houlsby, An analytical study of the cone penetration test in clay, Géotechnique, 41(1) (1991) 17-34.
[14] R. Salgado, J. Mitchell, M. Jamiolkowski, Cavity expansion and penetration resistance in sand, Journal of Geotechnical and Geoenvironmental Engineering, 123(4) (1997) 344-354.
[15] A.G. Amuda, A. Hasan, F. Sahdi, S.N.L. Taib, Variable penetration rate testing for shear strength of peat–a review, International Journal of Geotechnical Engineering, 14(6) (2020) 673-685.
[16] H. Yu, L. Herrmann, R. Boulanger, Analysis of steady cone penetration in clay, Journal of Geotechnical and Geoenvironmental Engineering, 126(7) (2000) 594-605.
[17] D. Liyanapathirana, Arbitrary Lagrangian Eulerian based finite element analysis of cone penetration in soft clay, Computers and Geotechnics, 36(5) (2009) 851-860.
[18] J. Walker, H.-S. Yu, Analysis of the cone penetration test in layered clay, Géotechnique, 60(12) (2010) 939-948.
[19] A. Tolooiyan, K. Gavin, Modelling the cone penetration test in sand using cavity expansion and arbitrary Lagrangian Eulerian finite element methods, Computers and Geotechnics, 38(4) (2011) 482-490.
[20] M.M. Ahmadi, P. Byrne, R. Campanella, Cone tip resistance in sand: modeling, verification, and applications, Canadian Geotechnical Journal, 42(4) (2005) 977-993.
[21] M. Khodayari, M.M. Ahmadi, Excess Pore Water Pressure along the Friction Sleeve of a Piezocone Penetrating in Clay: Numerical Study, International Journal of Geomechanics, 20(7) (2020) 04020100.
[22] Hauser L, Schweiger HF. Numerical study on undrained cone penetration in structured soil using G- PFEM. Computers and Geotechnics. 2021 May 1;133:104061.
[23] D. Kolymbas, An outline of hypoplasticity, Archive of Applied mechanics, 61(3) (1991) 143-151.
[24] E. Bauer, Calibration of a comprehensive hypoplastic model for granular materials, Soils and Foundations, 36(1) (1996) 13-26.
[25] P.A. Von Wolffersdorff, A hypoplastic relation for granular materials with a predefined limit state surface, Mechanics of Cohesive‐frictional Materials: An International Journal on Experiments, Modelling and Computation of Materials and Structures, 1(3) (1996) 251-271.
[26] D. Mašín, Modelling of soil behaviour with hypoplasticity, Springer Series in Geomechanics and Geoengineering, Ó Springer Nature Switzerland AG, https://doi. org/10, 1007 (2019) 978-973.
[27] Sheng D, Kelly R, Pineda J, Bates L. Numerical study of rate effects in cone penetration test. In3rd international symposium on cone penetration testing, (2014) 419-428.
[28] T. Hamann, G. Qiu, J. Grabe, Application of a Coupled Eulerian–Lagrangian approach on pile installation problems under partially drained conditions, Computers and Geotechnics, 63 (2015) 279-290.
[29] B. Mohammadi-Haji, A. Ardakani, Calibration of a hypoplastic constitutive model with elastic strain range for Firoozkuh sand, Journal of Geotechnical and Geological Engineering, 38 (2020) 5279-5293.
[30] I. Herle, G. Gudehus, Determination of parameters of a hypoplastic constitutive model from properties of grain assemblies, Mechanics of Cohesive‐frictional Materials: An International Journal on Experiments, Modelling and Computation of Materials and Structures, 4(5) (1999) 461-486.
[31] T. Lunne, J.J. Powell, P.K. Robertson, Cone penetration testing in geotechnical practice, CRC Press, 2002.
[32] R. Cudmani, V. Osinov, The cavity expansion problem for the interpretation of cone penetration and pressuremeter tests, Canadian Geotechnical Journal, 38(3) (2001) 622-638.
[33] R. Salgado, Analysis of penetration resistance in sands, University of California, Berkeley, 1993.
[34] H. Mahmoodzadeh, M.F. Randolph, Penetrometer testing: effect of partial consolidation on subsequent dissipation response, Journal of Geotechnical and Geoenvironmental Engineering, 140(6) (2014) 0401- 4022.
[35] Bihs A, Long M, Nordal S, Paniagua P, Consolidation parameters in silts from varied rate CPTU tests, AIMS Geosciences, 7(4) (2021) 637-68.