Semianalytical Model of Unloading-Induced Pore-Water Pressure and Consequent Consolidation Settlement of Surcharge Preloading Railway Subgrade
Publication: International Journal of Geomechanics
Volume 22, Issue 11
Abstract
Surcharge preloading is a suitable foundation treatment for high-speed railways in soft soil regions. As a temporary preload on the foundation, the surcharge load must be removed before track construction. In this process, rebound deformation of the foundation and variation in the pore-water pressure have been widely observed. These phenomena significantly influence the further evolution process of foundation consolidation. Although Biot’s consolidation theory is suitable for unloading-induced soil consolidation, the conventional Laplace transform method for solving Biot’s equations entails a time-consuming procedure and cannot reflect the time-dependent characteristics of the preloading and unloading process. To address these issues, a time difference method is proposed in this work. The ordinary differential equation in the transformation domain is obtained using the backward two-step difference method, and a physical analytical solution of the plane strain problem of overloaded subgrade is obtained via the Fourier inverse transform method. The proposed solution is validated through a comparison with existing literature data and actual engineering practices. Finally, based on this calculation method, the influence of the surcharge preloading amount, loading time, and soil properties on pore-water pressure dissipation and distribution after surcharge preloading removal is investigated.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author on reasonable request.
Acknowledgments
This research was supported by the National Natural Science Foundation of China (Grant Number 51778485), the Science and Technology Commission of Shanghai Municipality (Grant Numbers 19DZ1201004, 21142200400), the Shanghai Municipal Science and Technology Major Project (2021SHZDZX0100), and the Fundamental Research Funds for the Central Universities, the People’s Republic of China.
References
Biot, M. A. 1941. “General theory of three-dimensional consolidation.” J. Appl. Phys. 12 (2): 155–164. https://doi.org/10.1063/1.1712886.
Biot, M. A. 1957. “The elastic coefficients of the theory of consolidation.” J. Appl. Mech 24 (2): 594–601.
Booker, J. R., and J. C. Small. 1982a. “Finite layer analysis of consolidation. I.” Int. J. Numer. Anal. Methods Geomech. 6 (2): 151–171. https://doi.org/10.1002/nag.1610060204.
Booker, J. R., and J. C. Small. 1982b. “Finite layer analysis of consolidation. II.” Int. J. Numer. Anal. Methods Geomech. 6 (2): 173–194. https://doi.org/10.1002/nag.1610060205.
Booker, J. R., and J. C. Small. 1987. “A method of computing the consolidation behaviour of layered soils using direct numerical inversion of laplace transforms.” Int. J. Numer. Anal. Methods Geomech. 11 (4): 363–380. https://doi.org/10.1002/nag.1610110405.
Chen, L., H. Wu, X. Chen, and J. He. 2021. “Secondary consolidation characteristics and settlement calculation of soft soil treated by overload preloading.” Hydrogeol. Eng. Geol. 48 (1): 138–145.
Fu, Y. B., H. H. Zhu, and J. Yang. 2009. “Experimental study on time-dependent properties and pore water pressure of soft soil under unloading.” Chin. J. Rock Mech. Eng. 28 (1): 3244–3249.
Geng, X., and H. S. Yu. 2017. “A large-strain radial consolidation theory for soft clays improved by vertical drains.” Géotechnique 67 (11): 1020–1028. https://doi.org/10.1680/jgeot.15.T.013.
Gong, X. 1996. Advanced soil mechanics. Hangzhou, China: Zhejiang University Press.
Han, W., S. Liu, and D. Zhang. 2011. “Characteristics and influencing factors analysis of propagation of pneumatic fracturing in soils.” China Civ. Eng. J. 44 (9): 87–93.
Han, W., S. Liu, and D. Zhang. 2013. “Model test study on reinforcement effect of combined method of vacuum preloading and pneumatic fracturing.” China Civ. Eng. J. 46 (10): 108–118.
Hao, Y., Y. Chen, and J. Wang. 2002. “Consolidation analysis for partially penetrating sand drain ground preloaded by surcharge.” China J. Highway Transp. 2: 39–42.
Ho, L., and B. Fatahi. 2015. “Analytical solution for the two-dimensional plane strain consolidation of an unsaturated soil stratum subjected to time-dependent loading.” Comput. Geotech. 67: 1–16. https://doi.org/10.1016/j.compgeo.2015.02.011.
Huang, L., B. Wang, and S. Zhou. 2013. “Centrifugal model test of pile-plank subgrade in soft ground.” Rock Soil Mech. 34 (1): 192–196.
Indraratna, B., C. Rujikiatkamjorn, and I. Sathananthan. 2006. “Analytical and numerical solutions for a single vertical drain including the effects of vacuum preloading.” Can. Geotech. J. 42 (4): 994–1014. https://doi.org/10.1139/t05-029.
Iwata, M., and M. S. Jami. 2010. “Analysis of combined electroosmotic dewatering and mechanical expression operation for enhancement of dewatering.” Drying Technol. 28 (7): 881–889. https://doi.org/10.1080/07373937.2010.490505.
Kumar, R., A. Miglani, and N. R. Garg. 2000. “Plain strain problem of poroelasticity using eigenvalue approach.” J. Earth Syst. Sci. 109 (3): 371–380. https://doi.org/10.1007/BF02702208.
Li, G., T. N. Nguyen, and A. C. Amenuvor. 2016. “Settlement prediction of surcharge preloaded Low embankment on soft ground subjected to cyclic loading.” Mar. Georesour. Geotechnol. 34 (2): 154–161. https://doi.org/10.1080/1064119X.2014.985860.
Li, G., T. Yang, and Z. Yin. 2006. “Study of mechanism about surcharge preloading method on the soft ground of highways.” Chin. J. Geotech. Eng. 7: 896–901.
Li, X., C. Wang, and Y. Liu. 2004. “Nonlinear characteristic analysis of permeability coefficient in the process of soil dewatering and drainage.” Chin. J. Underground Space Eng. 4: 438–440+562.
Li, Y.-C. 1999. “Finite element analysis for a finite conductivity fracture in an infinite poroelastic medium.” Int. J. Numer. Anal. Methods Geomech. 23 (3): 187–215. https://doi.org/10.1002/(SICI)1096-9853(199903)23:3%3C187::AID-NAG964%3E3.0.CO;2-L.
Lin, C., and G. Lei. 2017. “Responses of negative excess pore water pressure under unloading in one-dimensional swelling tests.” Rock Soil Mech.anics 38 (12): 3613–3618+26.
Lin, X. 1984. “A new equivalent conversion method for multi-layer system in flexible pavement design.” J. Tongji Univ. (Nat. Sci.) 3: 32–37.
Liu, S., W. Han, D. Zhang, and G. Du. 2012. “Field pilot tests on combined method of vacuum preloading and pneumatic fracturing for soft ground improvement.” Chin. J. Geotech. Eng. 34 (4): 591–599.
Lo, W., J. Chang, R. I. Borja, J.-H. Deng, and J.-W. Lee. 2021. “Mathematical modeling of consolidation in unsaturated poroelastic soils under fluid flux boundary conditions.” J. Hydrol. 595: 125671. https://doi.org/10.1016/j.jhydrol.2020.125671.
Lopez-Acosta, N. P., V. M. Pineda-Nunez, A. L. Espinosa-Santiago, M. J. Mendoza, M. Rufiar, and R. Garcia. “Assessment of the Settlement and Horizontal Displacement of Test Embankments with Preloading, Drains, and Vacuum in the Former Texcoco Lake, Mexico 2019.” In Proc., 16th Pan-American Conf. on Soil Mechanics and Geotechnical Engineering. London: International Society for Soil Mechanics and Geotechnical Engineering.
Nguyen, T. N., D. T. Bergado, M. Kikumoto, P. H. Dang, S. Chaiyaput, and P. C. Nguyen. 2021. “A simple solution for prefabricated vertical drain with surcharge preloading combined with vacuum consolidation.” Geotext. Geomembr. 49 (1): 304–322. https://doi.org/10.1016/j.geotexmem.2020.10.004.
Ni, P., K. Xu, G. Mei, and Y. Zhao. 2019a. “Effect of vacuum removal on consolidation settlement under a combined vacuum and surcharge preloading.” Geotext. Geomembr. 47 (1): 12–22. https://doi.org/10.1016/j.geotexmem.2018.09.004.
Ni, P. P., G. X. Mei, and Y. L. Zhao. 2019b. “Surcharge preloading consolidation of reclaimed land with distributed sand caps.” Mar. Georesour. Geotechnol. 37 (6): 671–682. https://doi.org/10.1080/1064119X.2018.1482389.
Shan, Y., W. Xiao, K. Xiang, B. Wang, and S. Zhou. 2022. “Semi-automatic construction of pile-supported subgrade adjacent to existing railway.” Autom. Constr. 134: 104085. https://doi.org/10.1016/j.autcon.2021.104085.
Shan, Y., S. Zhou, B. Wang, and C. L. Ho. 2020. “Differential settlement prediction of ballasted tracks in bridge-embankment transition zones.” J. Geotech. Geoenviron. Eng. 146 (9): 04020075. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002307.
Tanaka, H., A. Tsutsumi, and T. Ohashi. 2014. “Unloading behavior of clays measured by CRS test.” Soils Found. 54 (2): 81–93. https://doi.org/10.1016/j.sandf.2014.02.001.
Wang, J., Z. Fang, Y. Cai, J. Chai, P. Wang, and X. Geng. 2018. “Preloading using fill surcharge and prefabricated vertical drains for an airport.” Geotext. Geomembr. 46 (5): 575–585. https://doi.org/10.1016/j.geotexmem.2018.04.013.
Wang, J., Z. Gao, H. Fu, G. Ding, Y. Cai, X. Geng, and C. Shi. 2019. “Effect of surcharge loading rate and mobilized load ratio on the performance of vacuum–surcharge preloading with PVDs.” Geotext. Geomembr. 47 (2): 121–127. https://doi.org/10.1016/j.geotexmem.2018.12.001.
Wang, J., B. Wang, Y. Zhou, and H. Zhang. 2016. “Calculation method for settlement of soft soil beneath high-speed railway.” Chin. J. Underground Space Eng. 12 (1): 196–204.
Wang, J., H. Zhuang, L. Guo, Y. Cai, M. Li, and L. Shi. 2022. “Secondary compression behavior of over-consolidated soft clay after surcharge preloading.” Acta Geotech. 17: 1009–1016.
Wang, L., C. Qi, J. Zheng, Y. Cui, Y. Shan, and R. Zheng. 2020. “Model test study on electroosmotic composite foundations.” Chin. J. Rock Mech. Eng. 39 (12): 2557–2569.
Yang, T., and G. Li. 2006. “Settlement rate method for determining surcharge removal time for embankment on soft ground.” Chin. J. Geotech. Eng. 28 (11): 1942–1946.
Yao, R. D., P. P. Ni, G. X. Mei, and Y. L. Zhao. 2019. “Numerical analysis of surcharge preloading consolidation of layered soils via distributed sand blankets.” Mar. Georesour. Geotechnol. 37 (8): 902–914. https://doi.org/10.1080/1064119X.2018.1506529.
Zhang, G., J. Wang, J. Wei, and H. Xu. 2007. “Study on theory of unloading control of surcharge preloading.” Rock Soil Mech. 28 (6): 1250–1254.
Zhang, G., J. Wang, and H. Xu. 2003. “Study on surcharge ratio and unloading control of surcharge precompression.” J. Civ. Eng. Manage. 20 (4): 37–39.
Zhang, G., Y. Wu, and Z. Li. 1999. “Study on threshold value of surcharge precompression.” Rock Soil Mech. 1: 80–84.
Zhang, J., J. Qian, H. Zhang, and L. Han. 2013. “Numerical analysis of oversized deep soft foundation improved by plastic drainge plates combined with surcharge preloading.” Chin. J. Geotech. Eng. 35 (2): 892–896.
Zhang, K., Y. Xiong, Y. Xia, and X. Liu. 2011. “Numerical analysis of surcharge preloading consolidation effects on soft foundation.” Rock Soil Mech. 32 (1): 648–651.
Zhou, S., B. Wang, and Y. Shan. 2020a. “Review of research on high-speed railway subgrade settlement in soft soil area.” Railway Eng. Sci. 28 (1): 129–145. https://doi.org/10.1007/s40534-020-00214-x.
Zhou, Z., C. Chen, and S. Xiao. 2020b. “Model tests on stress and deformation properties of composite foundation with controllable rigid piles and drainage bodies.” Chin. J. Geotech. Eng. 42 (12): 2308–2315.
Information & Authors
Information
Published In
International Journal of Geomechanics
Volume 22 • Issue 11 • November 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Nov 12, 2021
Accepted: May 9, 2022
Published online: Aug 22, 2022
Published in print: Nov 1, 2022
Discussion open until: Jan 22, 2023
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.