بررسی تأثیر وقوع پدیدة انسداد در ستون دانه‌ای بر رفتار سیکلیک و فرا سیکلیک زمین بهسازی شده با آن

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده فنی و مهندسی، دانشگاه قم، قم، ایران

2 دانشکده عمران، هنر و معماری، دانشگاه آزاد اسلامی- واحد علوم و تحقیقات، تهران، ایران

چکیده

در مطالعة حاضر تلاش شد تا با شبیه سازی یک تودة خاک سُست مسلح شده با ستون دانه‌ای (با و بدون روکش ژئوگریدی) در سلول دستگاه سه محوری، تأثیر وقوع پدیدة انسداد در ستون­های دانه‌ای بر رفتار زمین بهسازی شده با آن قبل و پس از تجربه بار سیکلیک مورد ارزیابی قرار گیرد. برای این منظور، از آزمایشات زهکشی‌نشده جهت شبیه سازی پدیدة انسداد در ستون­‌های دانه‌ای و آزمایشات مونوتونیک و سیکلیک-مونوتونیک برای شبیه سازی رفتار زمین قبل و پس از تجربه بار سیکلیک استفاده شد. رفتار نمونه‌ها قبل از تجربه بار سیکلیک و افزایش 73 درصدی مدول تغییرشکل به دلیل افزایش سختی روکش در شرایط کوتاه مدت در مقایسه با افزایش 105 درصدی در شرایط بلند مدت نشان داد که بهبود مدول تغییرشکل به دلیل استفاده از روکش سخت‌تر در صورت انسداد ستون‌های دانه‌ای و کاهش ظرفیت زهکشی آن‌ها کمتر از حد انتظار خواهد بود. همچنین مشخص شد که در خلال تجربه بار سیکلیک، هنگامی استفاده از روکش ژئوسنتتیکی در کاهش نشست‌های تجمعی و کاهش پتانسیل روانگرایی مؤثر خواهد بود که سختی کششی آن به اندازه کافی بزرگ باشد. از سوی دیگر، رفتار نمونه‌ها پس تجربه بار سیکلیک نشان داد که استفاده از ستون‌های دانه‌ای با روکش ژئوسنتتیکیِ سخت می­تواند وابستگی مدول تغییرشکل زمین به تغییرات دامنة بارگذاری سیکلیک را به حدی کاهش ‌دهد که ارزیابی تغییرشکل زمین ناشی از بارهای سیکلیک بتواند مستقل از دامنة بارگذاری انجام شود. همچنین مشخص شد که استفاده از روکش ژئوگریدی با سختی مناسب پیرامون ستون­‌های دانه‌­ای نقش چشمگیری در ممانعت از اُفت مقاومت زمین مسلح شده با ستون‌های دانه‌ای پس از تجربه بارهای سیکلیک ایفا می­‌کند، به ویژه هنگام تجربة بارهای بزرگ و همچنین پس از وقوع روانگرایی احتمالی.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Investigating the Effect of Clogging in a Granular Column on the Cyclic and Post-cyclic Behavior of Soft Ground Improved with it

نویسندگان [English]

  • majid yazdandoust 1
  • Amin Bastami 2
1 Department of Civil Engineering, University of Qom, Qom, IRAN
2 Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, IRAN
چکیده [English]

An attempt was made in the present study to evaluate the pre-and post-liquefaction behavior of the soft ground improved by granular columns (with and without a geogrid encasement) by simulating a loose soil mass reinforced with a granular column in a triaxial cell. For this purpose, a series of large-scale monotonic compressive tests and also stress-controlled cyclic triaxial tests followed by drained and undrained monotonic compression tests were carried out on the loose sand specimens including the granular column with and without geogrid encasement. The pre-cyclic behavior of specimens showed that the deformation modulus improvement due to the use of a stiffer encasement would be less noticeable in case of clogged granular columns. It was found that during a cyclic loading, the use of geogrid encasement will be effective in reducing cumulative settlements and mitigating the liquefaction potential when its tensile stiffness is large enough. Moreover, the post-cyclic behavior of specimens showed that the use of granular columns (whether encased or non-encased) decreased the dependence of the ground deformation modulus on the CSR changes so that the evaluation of the cyclic-induced ground deformation can be done completely independent of the cyclic loading magnitude. It was also found that the use of an encasement with appropriate stiffness played an important role in minimizing the loss of the strength of the ground stabilized by granular columns after experiencing cyclic loads, especially under large earthquakes and after the occurrence of possible liquefaction.

کلیدواژه‌ها [English]

  • Granular Column
  • Geogrid Encasement
  • Triaxial Test
  • Pre-and Post-Cyclic Behavior
  • Liquefaction

مراجع

[1] M. Gu, X. Cai, H. Mo, Q. Wang. “Unconfined compressive behavior of column with geogrid-encased recycled aggregate: Test and simulation.” Construction and Building Materials 400 (2023): 132528. ‏
[2] A.R. Ghanizadeh, A. Ghanizadeh, P.G. Asteris, P. Fakharian, D.J. Armaghani. “Developing bearing capacity model for geogrid-reinforced stone columns improved soft clay utilizing MARS-EBS hybrid method.” Transportation Geotechnics 38(2023): 100906. ‏
[3] B.K. Pandey, S. Rajesh, S. Chandra. “Time-Dependent Behavior of Embankment Resting on Soft Clay Reinforced with Encased Stone Columns.” Transportation Geotechnics 36(2022): 100809.
[4] L. Zhang, L. Wang, A. Zhou, Y Xu, X. Xia. “Semi-analytical solutions to the consolidation of unsaturated composite ground enforced by stone columns under equal strain condition considering smear effect.” Transportation Geotechnics 31(2021): 100644. ‏
[5] E. Aghili, I. Hosseinpour, R.J. Chenari, H. Ahmadi. “Behavior of granular column-improved clay under cyclic shear loading.” Transportation Geotechnics 31(2021): 100654.
[6] Z. Guetif, M. Bouassida, J.M. Debats. “Improved soft clay characteristics due to stone column installation.” Computers and Geotechnics 34(2) (2007): 104-111.
[7] J.A. Black, V. Sivakumar, A. Bell. “The settlement performance of stone column foundations.” Géotechnique 61(11) (2011): 909-922.
[8] Y.G. Zhou, K. Liu, Z.B. Sun, Y.M. Chen. “Liquefaction mitigation mechanisms of stone column-improved ground by dynamic centrifuge model tests.” Soil Dynamics and Earthquake Engineering 150 (2021): 106946.
[9] M. Ghazavi, J.N. Afshar. “Bearing capacity of geosynthetic encased stone columns.” Geotextiles and Geomembranes 38(2013): 26-36.
[10] B.K., Pandey, S. Rajesh, S. Chandra. “Performance enhancement of encased stone column with conductive natural geotextile under k0 stress condition.” Geotextiles and Geomembranes 49(5) (2021): 1095-1106.
[11] K. Deb, S. Shiyamalaa. “Effect of Clogging on Rate of Consolidation of Stone Column–Improved Ground by Considering Particle Migration.” International Journal of Geomechanics 16(1) (2016): 1-10.
[12] J. Sun, M. Lu, B. Xu, J. Shan. “Consolidation of high replacement ratio stone column-reinforced ground: Analytical solutions incorporating clogging effect.” Journal of Rock Mechanics and Geotechnical Engineering 16(8) (2024): 3311-3326.
[13] S. Pal, K. Deb. “Filtration performance of geotextile encasement to minimize the clogging of stone column during soil liquefaction.” Geotextiles and Geomembranes 49(3) (2021): 771-788.
[14] K. Adalier, A. Elgamal. “Mitigation of liquefaction and associated ground deformations by stone columns.” Engineering Geology 72(3-4) (2004): 275-291.
[15] N. Rahman, M. Rokonuzzaman, T. Sakai, S. Rahman. “Behavior of Floating Stone Columns in Soft Clay: Field Tests and Numerical Analysis.” International Journal of Geomechanics 25(6) (2025): 04025094. ‏
[16] S. Pal, K. Deb. “Post-earthquake Reconsolidation Settlement of Stone Column-Treated Liquefiable Sand.” International Journal of Geomechanics 20(10) (2020): 04020183.
[17] W. Van Impe, P. Silence. “Improving of the bearing capacity of weak hydraulic fills by means of geotextiles.” In Proceedings of the 3rd international conference on geotextiles, Vienna, Austria (1986) pp. 1411-1416.
[18] C.S. Wu, Y.S. Hong. “Laboratory tests on geosynthetic-encapsulated sand columns.” Geotextiles and Geomembranes 27(2) (2009): 107-120.
[19] N. Kumar, R. Kumar. “Performance of geosynthetic-encased stone columns in sandy soils subjected to vertical cyclic loads.” International Journal of Geomechanics 25(1) (2025): 04024323.
[20] M. Gu, X. Cai, J. Qiu, X. Zhang, D. Han “Dynamic Behavior of Stone Column–Improved Soft Clay under Three-Stage Traffic Loads.” International Journal of Geomechanics 25(1) (2025): 04024322.
[21] Z. Xu, L. Zhang, S. Zhou. “Influence of encasement length and geosynthetic stiffness on the performance of stone column: 3D DEM-FDM coupled numerical investigation.” Computers and Geotechnics 132 (2021):103993.
[22] L. Tang, S. Cong, X. Ling, J. Lu, A. Elgamal. “Numerical study on ground improvement for liquefaction mitigation using stone columns encased with geosynthetics.” Geotextiles and Geomembranes 43(2) (2015): 190-195.
[23] C. Cengiz, E. Güler. “Seismic behavior of geosynthetic encased columns and ordinary stone columns.” Geotextiles and Geomembranes 46(1) (2018): 40-51.
[24] C. Cengiz, E. Guler. “Shaking table tests on geosynthetic encased columns in soft clay.” Geotextiles and Geomembranes 46(6) (2018): 748-758.
[25] C. Cengiz, E. Guler. “Load bearing and settlement characteristics of Geosynthetic Encased Columns under seismic loads.” Soil Dynamics and Earthquake Engineering 136(2020): 106244.
[26] C. Yoo, Q. Abbas. “Laboratory investigation of the behavior of a geosynthetic encased stone column in sand under cyclic loading.” Geotextiles and Geomembranes 48(4) (2020): 431-442.
[27] V. SivakumarD., McKelvey, J. Graham, D. Hughes. “Triaxial tests on model sand columns in clay.” Canadian Geotechnical Journal 41(2) (2004): 299-312.
[28] J. Xue, Z. Liu, J. Chen. “Triaxial compressive behaviour of geotextile encased stone columns.” Computers and Geotechnics 108 (2019): 53-60.
[29] R.D. Barksdale, R.C. Bachus. “Design and construction of stone columns.” Vol. 1, report no. FHWA/RD-83/026, National technical information service, Springfield, Virginia (1983).
[30] N.P. Balaam, J.R. Booker. “Analysis of rigid rafts supported by granular piles.” International journal for numerical and analytical methods in geomechanics 5(4) (1981): 379-403.
[31] D. Muir Wood, W. Hu, D.F.T. Nash. “Group effects in stone column foundations: model tests.” Geotechnique 50(6) (2000): 689-698.
[32] S. Rajesh. “Time-dependent behaviour of fully and partially penetrated geosynthetic encased stone columns.” Geosynthetics International 24(1) (2017): 60-71.
[33] M. Hasan, N.K. Samadhiya. “Performance of geosynthetic-reinforced granular piles in soft clays: Model tests and numerical analysis.” Computers and Geotechnics 87(2017): 178-187.
[34] Y. Zhou, G. Kong. “Deformation analysis of a geosynthetic-encased stone column and surrounding soil using cavity-expansion model.” International Journal of Geomechanics 19(5) (2019): 04019036.
[35] M. Gu, J. Han, M. Zhao. “Three-Dimensional DEM Analysis of Axially Loaded Geogrid-Encased Stone Column in Clay Bed.” International Journal of Geomechanics 20(3) (2020): 04019180.
[36] J.F. Chen, X.T. Wang, J.F. Xue, Y. Zeng, S.Z. Feng. “Uniaxial compression behavior of geotextile encased stone columns.” Geotextiles and Geomembranes 46(3) (2018): 277-283.
[37] M. Gu, M. Zhao, L. Zhang, J. Han. “Effects of geogrid encasement on lateral and vertical deformations of stone columns in model tests.” Geosynthetics International 23(2) (2016): 100-112.
[38] L. Zhang, Z. Xu, S. Zhou. “Vertical cyclic loading response of geosynthetic-encased stone column in soft clay.” Geotextiles and Geomembranes 48(6) (2020): 897-911.
[39] M. Miranda, A. Da Costa, J. Castro, C. Sagaseta. “Influence of geotextile encasement on the behavior of stone columns: Laboratory study.” Geotextiles and Geomembranes 45(1) (2017): 14-22.
[40] L.Y. Li, S. Rajesh, J.F. Chen. “Centrifuge model tests on the deformation behavior of geosynthetic-encased stone column supported embankment under undrained condition.” Geotextiles and Geomembranes 49(3) (2021): 550-563.
[41] K. Liu, R. Qiu, T. Yan, B. Wu, J. Fan, F. Yue, G. Mei. “Model test of clogging effects on composite foundation of geosynthetic-encased steel slag column.” Geotextiles and Geomembranes 50(5) (2022): 858-867.
[42] K. Ishihara, F. Tatsuoka, S. Yasuda. “Undrained deformation and liquefaction of sand under cyclic stresses.” Soils and foundations 15(1) (1975): 29-44.
[43] X. Mao, M. Fahey. “Behaviour of calcareous soils in undrained cyclic simple shear.” Géotechnique 53(8) (2003): 715-727.
[44] I.M. Idriss, R. Dobry, R.D. Singh. “Nonlinear behavior of soft clays during cyclic loading.” Journal of the Geotechnical Engineering Division 104(GT12) )1978(: 1427–1447.
[45] A.F. Hyde, T. Higuchi, K. Yasuhara. “Liquefaction, cyclic mobility, and failure of silt.” Journal of geotechnical and geoenvironmental engineering 132(6) (2006): 716-735.
[46] R. Howell, E.M. Rathje, R. Kamai, R. Boulanger. “Centrifuge modeling of prefabricated vertical drains for liquefaction remediation.” Journal of geotechnical and geoenvironmental engineering 138(3) (2012): 262-271.
[47] S.M.R. Hosseini, S.A. Naeini, M. Hassanlourad. “Monotonic, cyclic and post-cyclic behaviour of an unsaturated clayey soil.” International Journal of Geotechnical Engineering 11(3) (2017): 225-235.
[48] Y.Y. Ko, C.H. Chen. “On the variation of mechanical properties of saturated sand during liquefaction observed in shaking table tests.” Soil Dynamics and Earthquake Engineering 129 (2020): 105946.
نشریه مهندسی عمران امیرکبیر
دوره 57، شماره 7
مهر 1404
صفحه 1113-1138

فایل ها

هم رسانی

ارجاع به این مقاله

آمار