3D Numerical Assessment of Rammed Aggregate Pier Performance under Dynamic Loading in Liquefiable Soils
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 149, Issue 3
Abstract
Ground improvement (GI) techniques have shown promise in effective liquefaction mitigation, but the physical mechanisms governing their three-dimensional (3D) response during dynamic loading are not yet fully understood. To evaluate the 3D performance of one GI technique, the rammed aggregate pier (RAP), in-situ site characterization, full-scale field test data, and calibrated baseline constitutive soil model parameters are combined to model the 3D fully coupled hydromechanical response of natural (unreinforced) and improved (reinforced) soil profiles. To the authors’ knowledge, this contribution represents the first 3D model of a columnar-reinforced soil profile being calibrated using full-scale field testing. The field observations from the comprehensive ground improvement testing (GIT) program in New Zealand and insights from two-dimensional (2D) finite-difference analyses using constitutive model parameters calibrated against the field measurements were used. The developed 3D models were subjected to dynamic loads simulating the excitation generated by a vibroseis truck at one of the in-situ test sites of the GIT program, as well as unidirectional and bidirectional earthquake ground motions from the Canterbury Earthquake Sequence events. The 3D simulations showed that the improved soil profiles experienced reduced excess pore pressures and reduced dynamically induced shear strains compared to the natural, unreinforced soil models. The developed 3D finite-element predictions were compared and validated vis-à-vis the field observations of the GIT program. Compared to 2D analyses, 3D analyses provide a more accurate description of actual field conditions, and, for instance, it was observed that multidirectional shaking has a significant effect on liquefaction triggering, particularly for natural soil profiles. Finally, it was shown that soil densification around the installed pier elements and the lateral earth pressure increase within the densified soil and are the primary ground improvement mechanisms contributing to the reduction of dynamically induced shear deformations and excess pore pressure generation during earthquake shaking. It was also found that the permeability and shear stiffness of the installed RAP piers did not have a significant influence on the pore pressure response and shear strains developed along the centerline of the improved area.
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Data Availability Statement
Some data that support the findings of this study are available from the authors upon reasonable request.
Acknowledgments
Funding for this research was provided by Geopier Foundation Company. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of Geopier Foundation Company.
References
Ashford, S. A., K. M. Rollins, and J. D. Lane. 2004. “Blast-induced liquefaction for full-scale foundation testing.” J. Geotech. Geoenviron. Eng. 130 (8): 798–806. https://doi.org/10.1061/(ASCE)1090-0241(2004)130:8(798).
Beaty, M. H., and P. M. Byrne. 2011. “UBCSAND constitutive model version 904aR.” Accessed March 10, 2021. https://www.itascacg.com/software/udm-library/ubcsand.
Boulanger, R. W., and K. Ziotopoulou. 2018. PM4Sand (Version 3.1): A sand plasticity model for earthquake engineering applications. Davis, CA: Univ. of California.
Cubrinovski, M., R. A. Green, and L. Wotherspoon. 2011. Geotechnical reconnaissance of the 2011 Christchurch, New Zealand earthquake. Berkeley, CA: Geotechnical Extreme Events Reconnaissance Association.
Dimitriadi, V., G. Bouckovalas, Y. Chaloulos, and A. Aggelis. 2017. “Seismic liquefaction performance of strip foundations: Effect of ground improvement dimensions.” Soil Dyn. Earthquake Eng. 106 (8): 298–307. https://doi.org/10.1016/j.soildyn.2017.08.021.
Galavi, V., A. Petalas, and R. B. J. Brinkgreve. 2013. “Finite element modeling of seismic liquefaction in soils.” Geotech. Eng. J. SEAGS & AGSSEA 44 (3): 55–64.
Green, R. A., and J. Lee. 2012. “Liquefaction 560 risk mitigation.” In Deep foundations. Hawthorne, NJ: The Magazine for the Deep Foundations Institute.
Green, R. A., B. W. Maurer, and S. van Ballegooy. 2018. “The influence of the non-liquefied crust on the severity of surficial liquefaction manifestations: Case history from the 2016 Valentine’s Day earthquake in New Zealand.” In Proc., Geotechnical Earthquake Engineering and Soil Dynamics V (GEESD V), Geotechnical Special Publication 290, edited by S. J. Brandenberg and M. T. Manzari, 21–32. Reston, VA: ASCE.
Green, R. A., C. G. Olgun, and K. J. Wissmann. 2008. “Shear stress redistribution as a mechanism to mitigate the risk of liquefaction.” In Proc., Geotechnical Earthquake Engineering And Soil Dynamics, Geotechnical Special Publication 181, edited by D. Zeng, M. T. Manzari, and D. R. Hiltunen, 1–10. Reston, VA: ASCE.
Hutabarat, D., and J. D. Bray. 2021. “Effective stress analysis of liquefiable sites to estimate the severity of sediment ejecta.” J. Geotech. Geoenviron. Eng. 147 (5): 04021024. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002503.
Idriss, I. M., and R. W. Boulanger. 2008. Soil liquefaction during earthquakes. Oakland, CA: Earthquake Engineering Research Institute.
Ishihara, K. 1985. “Stability of natural deposits during earthquakes.” In Proc., 11th Int. Conf. on Soil Mechanics and Foundation Engineering. Rotterdam, Netherlands: A. A. Balkema.
Itasca. 2016. FLAC—Fast Lagrangian analysis of continua, Version 8.0. Minneapolis: Itasca Consulting Group.
Kammerer, A., J. Wu, M. Riemer, J. Pestana, and R. Seed. 2004. “Shear strain development in liquefiable soil under bi-directional loading conditions.” In Proc., 13th World Conf. on Earthquake Engineering. Vancouver, BC, Cananda: 13 WCEE Secretariat.
Kottke, A., and E. Rathje. 2008. Technical manual for STRATA. Berkeley, CA: Pacific Earthquake Engineering Research.
Pyke, R., B. Seed, and C. Chan. 1975. “Settlement of sand under multi-directional shaking.” J. Geotech. J. Div. 101 (4): 379–398. https://doi.org/10.1061/AJGEB6.0000162.
Rathje, E. M., W. J. Chang, and K. H. Stokoe. 2005. “Development of an in situ dynamic liquefaction test.” Geotech. Test. J. 28 (1): 50–60.
Roberts, J. N. 2017. “Field evaluation of large-scale, shallow ground improvements to mitigate liquefaction triggering.” Ph.D. thesis, Dept. of Civil, Architectural and Environmental Engineering, Univ. of Texas at Austin.
Saftner, D. A., J. Zheng, R. A. Green, R. Hryciw, and K. Wissman. 2018. “Rammed aggregate pier installation effect on soil properties.” Proc. Inst. Civ. Eng. 171 (2): 63–73. https://doi.org/10.1680/jgrim.16.00021.
Seed, H. B., I. M. Idriss, F. Makdisi, and N. Banerjee. 1975. Representation of irregular stress time histories by equivalent uniform stress series in liquefaction analysis. Berkeley, CA: Earthquake Engineering Research Center.
Seed, R. B., et al., 2003. “Recent advances in soil liquefaction engineering: A unified and consistent framework.” In Proc., 26th Annual ASCE Los Angeles Geotechnical Spring Seminar. Berkeley, CA: Earthquake Engineering Research Center.
Thum, T. S., A. Yerro, A. Saade, E. Ye, K. Wissmann, and R. A. Green. 2021. “Numerical modeling of rammed aggregate piers (RAP) in liquefiable soil.” Soil Dyn. Earthquake Eng. 153 (Feb): 107088. https://doi.org/10.1016/j.soildyn.2021.107088.
Tiznado, J. C., S. Dashti, C. Ledezma, B. P. Wham, and M. Badanagki. 2020. “Performance of embankments on liquefiable soils improved with dense granular columns: Observations from case histories and centrifuge experiments.” J. Geotech. Geoenviron. Eng. 146 (9): 04020073. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002309.
van Ballegooy, S., J. Roberts, K. Stokoe, B. Cox, F. Wentz, and S. Hwang. 2015. “Large-scale testing of shallow ground improvements using controlled stage-loading with T-Rex.” In Proc., 6th Int. Conf. on Earthquake Geotechnical Engineering. London: International Society of Soil Mechanics and Geotechnical Engineering.
van Ballegooy, S., F. Wentz, K. Stokoe, B. Cox, K. Rollins, S. Ashford, and M. Olsen. 2017. Christchurch ground improvement trial report. Auckland, NZ: Tonkin & Taylor.
White, D. J., H. T. Pham, and K. K. Hoevelkamp. 2007. “Support mechanisms of rammed aggregate piers. I: Experimental results.” J. Geotech. Geoenviron. Eng. 133 (12): 1503–1512. https://doi.org/10.1061/(ASCE)1090-0241(2007)133:12(1503).
White, D. J., M. T. Sulieman, H. T. Pham, and J. Bigelow. 2002. Constitutive equations for aggregates used in geopier foundation construction. Ames, IA: Iowa State Univ.
Wissmann, K. J., S. van Ballegooy, B. C. Metcalfe, J. Dismuke, and C. Anderson. 2015. “Rammed aggregate pier ground improvement as a liquefaction mitigation method in sandy and silty soils.” In Proc., 6th Int. Conf. on Earthquake Geotechnical Engineering. London: International Society of Soil Mechanics and Geotechnical Engineering.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 149 • Issue 3 • March 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Feb 9, 2022
Accepted: Oct 25, 2022
Published online: Jan 3, 2023
Published in print: Mar 1, 2023
Discussion open until: Jun 3, 2023
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