Field Test Verification and Consolidation Model of a Sand-Doped Soft Soil Foundation with Vacuum Pressure
Publication: International Journal of Geomechanics
Volume 23, Issue 7
Abstract
In this study, a field test on the consolidation of sand-doped improved soft soil under surcharge-vacuum preloading is carried out. By analyzing the vacuum pressure transmission efficiency, the settlement rate, and the dissipation rule of excess pore-water pressure of sand-doped and original soft soil foundation in the consolidation process and comparing the indices of vane shear strength, water content, and void ratio before and after consolidation, the technical superiority and reinforcement effect of the sand mixing method for improving soft soil are comprehensively evaluated. Considering the fact that the vacuum pressure decreases linearly along the depth and the surcharge preloading is applied linearly, an assumption of equal volumetric strain is introduced to reflect the lateral deformation, and an axisymmetric nonlinear radial consolidation model of sand-doped soft soil is established. The model accuracy is verified by model degradation research and a field test. The results show that the sand-doped method (20% sand content) can improve the transmission efficiency of vacuum pressure, reduce the loss of vacuum pressure along the prefabricated vertical drains, accelerate the dissipation rate of excess pore-water pressure, increase the final settlement and shear strength, reduce the final void ratio and water content, and improve the reinforcement effect of deep soil. A nonlinear consolidation solution of the sand-doped soil with linear surcharge preloading considering the actual negative boundary conditions can reflect the consolidation behavior more accurately. If lateral deformation and linear surcharge preloading are not considered, the consolidation rate of soil will be overestimated.
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Acknowledgments
This research is supported by the National Natural Science Foundation of China (Grant No. 52178347), the Jiangsu South-to-North Water Diversion Project (Grant No. JSNSBD201910), project ZR2021ME068 supported by the Shandong Provincial Natural Science Foundation, the Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University (Grant No. 2021006), and the Jiangsu Funding Program for Excellent Postdoctoral Talent.
References
Al-Badran, Y. M. 2020. “Effect of adding sand on clayey soil compressibility.” Key Eng. Mater. 857: 328–333. https://doi.org/10.4028/www.scientific.net/KEM.857.328.
Amri, S., M. Akchiche, A. Bennabi, and R. Hamzaoui. 2019. “Geotechnical and mineralogical properties of treated clayey soil with dune sand.” J. Afr. Earth Sci. 152: 140–150. https://doi.org/10.1016/j.jafrearsci.2019.01.010.
Asha, B. S., and J. N. Mandal. 2015. “Laboratory performance tests on natural prefabricated vertical drains in marine clay.” Proc. Inst. Civ. Eng. Ground Improv. 168 (1): 45–65. https://doi.org/10.1680/grim.13.00001.
Barron, R. A. 1948. “Consolidation of fine-grained soils by drain wells.” Trans. ASCE 113 (1): 718–754. https://doi.org/10.1061/TACEAT.0006098.
Basak, P., and R. Madhav. 1978. “Analytical solutions of sand drain problems.” J. Geotech. Eng. Div. 104 (1): 129–135. https://doi.org/10.1061/AJGEB6.0000555.
Bergado, D. T., J. C. Chai, N. Miura, and A. S. Balasubramaniam. 1998. “PVD improvement of soft Bangkok clay with combined vacuum and reduced sand embankment preloading.” J. Geotech. Eng. 29 (1): 95–121.
Bian, X., L. L. Zeng, F. Ji, and M. Xie. 2022a. “Plasticity role in strength behaviour of cement-phosphogypsum stabilized soils.” J. Rock Mech. Geotech. Eng. 14 (6): 1977–1988. https://doi.org/10.1016/j.jrmge.2022.01.003.
Bian, X., W. Zhang, X. Z. Li, X. S. Shi, Y. F. Deng, and J. Peng. 2022b. “Changes in strength, hydraulic conductivity and microstructure of superabsorbent polymer stabilized soil subjected to wetting–drying cycles.” Acta Geotech. 17: 5043–5057. https://doi.org/10.1007/s11440-022-01573-x.
Cai, Y., H. Qiao, J. Wang, X. Geng, P. Wang, and Y. Cai. 2017. “Experimental tests on effect of deformed prefabricated vertical drains in dredged soil on consolidation via vacuum preloading.” Eng. Geol. 222: 10–19. https://doi.org/10.1016/j.enggeo.2017.03.020.
Cao, Y. P., J. W. Xu, X. Bian, and G. Z. Xu. 2019. “Effect of clogging on large strain consolidation with prefabricated vertical drains by vacuum pressure.” KSCE J. Civ. Eng. 23 (10): 4190–4200. https://doi.org/10.1007/s12205-019-1884-2.
Cao, Y. P., J. Zhang, J. W. Xu, and G. Z. Xu. 2020. “A large-strain vacuum-assisted radial consolidation model for dredged sludge considering lateral deformation.” KSCE J. Civ. Eng. 24 (10): 1–12. https://doi.org/10.1007/s12205-020-1854-8.
Cao, Y. P., R. Zhang, G. Z. Xu, and J. W. Xu. 2021. “Axisymmetric large strain consolidation by vertical drains considering well resistance under vacuum pressure.” Arab. J. Geosci. 14 (19): 1–10. https://doi.org/10.1007/s12517-021-08354-y.
Chai, J. C., and J. P. Carter. 2011. Deformation analysis in soft ground improvement. Dordrecht, Netherlands: Springer.
Chai, J. C., Z. S. Hong, and S. L. Shen. 2010. “Vacuum-drain consolidation induced pressure distribution and ground deformation.” Geotext. Geomembr. 28 (3): 525–535. https://doi.org/10.1016/j.geotexmem.2010.01.003.
Chen, J., S. L. Shen, Z. Y. Yin, Y. S. Xu, and S. Horpibulsuk. 2016. “Evaluation of effective depth of PVD improvement in soft clay deposit: A field case study.” Mar. Georesour. Geotechnol. 34 (5): 420–430. https://doi.org/10.1080/1064119X.2015.1016638.
Chen, L. Z., Y. B. Gao, A. Elsayed, and X. M. Yang. 2019. “Soil consolidation and vacuum pressure distribution under prefabricated vertical drains.” Geotech. Geol. Eng. 37 (4): 3037–3048. https://doi.org/10.1007/s10706-019-00822-3.
Chu, J., S. W. Yan, and H. Yang. 2000. “Soil improvement by the vacuum preloading method for an oil storage station.” Géotechnique 50 (6): 625–632. https://doi.org/10.1680/geot.2000.50.6.625.
Ding, J., X. Wan, C. Zhang, Z. He, and L. Zhao. 2019. “Case study: Ground improvement of Yangtze river floodplain soils with combined vacuum and surcharge preloading method.” Int. J. Geomech. 19 (12): 05019008. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001516.
Farooq, K., and K. A. Virk. 2009. “Improvement of engineering characteristics of expansive clays by sand mixing.” In Proc., 17th Int. Conf. on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 785–788. Alexandria, Egypt: International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE).
Fu, H., Y. Cai, J. Wang, and P. Wang. 2017. “Experimental study on the combined application of vacuum preloading–variable-spacing electro-osmosis to soft ground improvement.” Geosynth. Int. 24 (1): 72–81. https://doi.org/10.1680/jgein.16.00016.
Geng, X., B. Indraratna, and C. Rujikiatkamjorn. 2012. “Analytical solutions for a single vertical drain with vacuum and time-dependent surcharge preloading in membrane and membraneless systems.” Int. J. Geomech. 12 (1): 27–42. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000106.
Guo, X., K. H. Xie, M. M. Lu, Y. B. Deng, and T. Huang. 2018. “Nonlinear analytical solution for consolidation of vertical drains by straight-line vacuum preloading method.” J. Cent. South Univ. 282 (2): 384–392. https://doi.org/10.11817/j.issn.1672%E2%88%927207.2018.02.017.
Hansbo, S. 1981. “Consolidation of fine-grained soils by prefabricated drains.” In Vol. 3 of Proc., 10th Int. Conf. on Soil Mechanics and Foundation Engineering, 677–682. Rotterdam, Netherlands: Publications Committee of X.ICSMFE.
Hansbo, S., M. Jamiolkowski, and L. Kok. 1981. “Consolidation by vertical drains.” Géotechnique 31 (1): 45–66. https://doi.org/10.1680/geot.1981.31.1.45.
Hassanlourad, M., M. H. Khatami, and M. M. Ahmadi. 2017. “Effects of sulphuric acid pollutant on the shear behaviour and strength of sandy soil and sand mixed with bentonite clay.” Int. J. Geotech. Eng. 11 (2): 114–119. https://doi.org/10.1080/19386362.2016.1193662.
Indraratna, B., C. Bamunawita, and H. Khabbaz. 2004. “Numerical modeling of vacuum preloading and field applications.” Can. Geotech. J. 41 (6): 1098–1110. https://doi.org/10.1139/T04-054.
Indraratna, B., I. Sathananthan, C. Rujikiatkamjorn, and A. S. Balasubramaniam. 2005a. “Analytical and numerical modeling of soft soil stabilized by prefabricated vertical drains incorporating vacuum preloading.” Int. J. Geomech. 5 (2): 114–124. https://doi.org/10.1061/(asce)1532-3641(2005)5:2(114).
Indraratna, B., C. Rujikiatkamjorn, and I. Sathananthan. 2005b. “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.
Jin, Q. B., Y. B. Li, and B. Li. 2019. “Consolidation behavior and elastic wave characteristics of lime-treated dredged mud with vacuum preloading.” Mar. Georesour. Geotechnol. 39 (2): 1–10. https://doi.org/10.1080/1064119X.2019.1679927.
Khan, A. Q., and G. Mesri. 2014. “Vacuum distribution with depth in vertical drains and soil during preloading.” Geomech. Eng. 6 (4): 377–389. https://doi.org/10.12989/gae.2014.6.4.377.
Kim, T. H., C. K. Kim, S. J. Jung, and J. H. Lee. 2007. “Tensile strength characteristics of contaminated and compacted sand–bentonite mixtures.” Environ. Geol. 52 (4): 653–661. https://doi.org/10.1007/s00254-006-0494-8.
Kong, L. W., X. M. Li, and H. N. Tian. 2011. “Effect of fines content on permeability coefficient of sand and its correlation with state parameters.” Rock Soil Mech. 32: 21–26+41. https://doi.org/10.16285/j.rsm.2011.s2.009.
Lei, G. H., L. D. Xu, Q. Zheng, and H. W. Wu. 2017. “Role of equal-strain assumption in unit-cell theory for consolidation with vertical drains.” J. Cent. South Univ. 24 (12): 2914–2923. https://doi.org/10.1007/s11771-017-3705-4.
Li, M. D., Q. S. Chen, K. J. Wen, S. Nimbalkar, and R. H. Dai. 2021. “Improved vacuum preloading method combined with sand sandwich structure for consolidation of dredged clay-slurry fill and original marine soft clay.” Int. J. Geomech. 21 (10): 04021182. https://doi.org/10.1061/(ASCE)GM.1943-5622.0002123.
Lu, M., S. Wang, S. W. Sloan, D. C. Sheng, and K. H. Xie. 2015. “Nonlinear consolidation of vertical drains with coupled radial–vertical flow considering well resistance.” Geotext. Geomembr. 43 (2): 182–189. https://doi.org/10.1016/j.geotexmem.2014.12.001.
Maatoug, S., N. Brahim, and A. Hatira. 2019. “Amendment of saline soils by adding sand in the old oasis of Nefzaoua in Tunisia.” Res. J. Appl. Sci. Eng. Technol. 16 (4): 153–159. https://doi.org/10.19026/rjaset.16.6019.
Mekkiyah, H. M., and A. Al-Khazragie. 2015. “Behavior of clay soil mixed with fine sand during consolidation.” Appl. Res. J. 1 (8): 437–443.
Mersi, G., and A. Q. Khan. 2012. “Ground improvement using vacuum loading together with vertical drains.” J. Geotech. Geoenviron. Eng. 138 (6): 680–689. https://doi.org/10.1061/(asce)gt.1943-5606.0000640.
Mukherjee, S., P. Ghosh, and T. Das. 2015. “A correlative study of different geotechnical parameters of local soil of West Bengal with varying percentage of sand.” Discovery 40 (184): 260–266.
Nguyen, B. P., and Y. T. Kim. 2019. “Radial consolidation of PVD installed normally consolidated soil with discharge capacity reduction using large strain theory.” Geotext. Geomembr. 47 (2): 243–254. https://doi.org/10.1016/j.geotexmem.2019.01.008.
Ong, C. Y., and J. C. Chai. 2011. “Lateral displacement of soft ground under vacuum pressure and surcharge load.” Front. Archit. Civ. Eng. China 5 (2): 239–248. https://doi.org/10.1007/s11709-011-0110-1.
Qiu, Q. C., H. H. Mo, and Z. L. Dong. 2008. “Vacuum pressure distribution and pore pressure variation in ground improved by vacuum preloading.” Can. Geotech. J. 44 (12): 1433–1445. https://doi.org/10.1139/T07-064.
Rujikiatkamjorn, C., and B. Indraratna. 2007. “Analytical solutions and design curves for vacuum-assisted consolidation with both vertical and horizontal drainage.” Can. Geotech. J. 44 (2): 188–200. https://doi.org/10.1139/t06-111.
Shi, X. S., and J. Yin. 2017. “Experimental and theoretical investigation on the compression behavior of sand–marine clay mixtures within homogenization framework.” Comput. Geotech. 90: 14–26. https://doi.org/10.1016/j.compgeo.2017.05.015.
Shi, X. S., and J. Yin. 2018. “Estimation of hydraulic conductivity of saturated sand–marine clay mixtures with a homogenization approach.” Int. J. Geomech. 18 (7): 04018082. https://doi.org/10.1061/(asce)gm.1943-5622.0001190.
Tang, M., and J. Q. Shang. 2000. “Vacuum preloading consolidation of Yaoqiang Airport runway.” Geotechnique 50 (6): 613–623. https://doi.org/10.1680/geot.2000.50.6.613.
Ural, N., and B. Görgün. 2019. “Effect of different sands on one-dimensional and hydraulic consolidation (radial) tests of clay.” Iran. J. Sci. Technol. Trans. Civ. Eng. 43 (Suppl 1): 331–341. https://doi.org/10.1007/s40996-018-0168-2.
Wang, J., Y. Cai, J. Ma, J. Chu, H. Fu, P. Wang, and Y. Jin. 2016. “Improved vacuum preloading method for consolidation of dredged clay-slurry fill.” J. Geotech. Geoenviron. Eng. 142 (11): 06016012. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001516.
Wang, J., Y. Cai, J. Ni, X. Geng, and F. Xu. 2017. “Effect of sand on the vacuum consolidation of dredged slurry.” Mar. Georesour. Geotechnol. 36 (2): 238–244. https://doi.org/10.1080/1064119x.2017.1304473.
Wu, Y. J., X. D. Wang, X. D. Zhang, Y. T. Lu, Y. Xu, Q. C. Tran, and V. Q. Vu. 2021. “Experimental study on the treatment of sludge discharged from an in situ soil washing plant by vacuum preloading.” Environ. Eng. Sci. 38 (9): 899–909. https://doi.org/10.1089/ees.2020.0340.
Xu, S. F., Z. Wang, and Y. Zhang. 2011. “Study on the hydraulic conductivity of sand–bentonite mixtures used as liner system of waste landfill.” Adv. Mater. Res. 194–196: 909–912. https://doi.org/10.4028/www.scientific.net/AMR.194-196.909.
Yan, Y. G., Z. L. Dong, C. B. Yang, P. S. Chen, and Q. C. Qiu. 2011. “Experimental study on effect of grain size distribution on improvement of dredger fill.” Chin. J. Geotech. Eng. 233 (11): 1775–1779.
Ye, G. B., Y. Xu, and Z. Zhang. 2018. “Performance evaluation of PVD-reinforced soft soil with surcharge and vacuum preloading.” Int. J. Civ. Eng. 16 (4): 421–433. https://doi.org/10.1007/s40999-016-0142-y.
Zhu, Q. F., C. S. Gao, S. H. Yang, L. Zhang, D. B. Li, and Z. C. Wang. 2010. “Transfer properties of vacuum degree in treatment of super-soft muck foundation.” Chin. J. Geotech. Eng. 32 (9): 1429–1433.
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International Journal of Geomechanics
Volume 23 • Issue 7 • July 2023
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© 2023 American Society of Civil Engineers.
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Received: Jul 11, 2022
Accepted: Feb 15, 2023
Published online: May 12, 2023
Published in print: Jul 1, 2023
Discussion open until: Oct 12, 2023
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