Dredged Clay Treatment Consolidation Theory by Air-Booster Vacuum Preloading
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 150, Issue 5
Abstract
Air-booster vacuum preloading (AVP) without sand blanket and surcharge vacuum preloading (SVP) methods were used to treat two adjacent areas in a foundation reinforcement project on Donghai Island, Zhanjiang City, Guangdong Province, China. In this study, engineering characteristics of the AVP foundation were obtained through analyzing monitoring data. Results showed that the AVP method obtained superior foundation consolidation results compared to SVP method. This study proposed a new simplified mechanical model for AVP, with a single PVD (prefabricated vertical drain) centered and the air-booster pipes symmetrically distributed around the PVD, applied equivalent air-booster pressure to the drainage boundary. Furthermore, this study established a mathematical analytical model for predicting consolidation settlement based on the proposed simplified model. By comparing the theoretical settlement value with the measured value, this paper verifies the rationality of the analytical solution. Finally, this study analyzed the effects of well resistance, smearing effect, compression index, and permeability index ratio on consolidation characteristics.
Practical Applications
Land reclamation projects will generate a large amount of dredged ultrasoft soil foundation. The AVP method can achieve superior foundation treatment effects by injecting gas into soil mass through air-booster pipes. The results of this case study demonstrate that the AVP method has substantial advantages compared to the conventional vacuum preloading method. The AVP method can increase foundation settlement, shorten the time for foundation treatment construction, and improve the foundation reinforcement effect. In addition, the AVP method can alleviate PVD clogging and maintain soil permeability, while simultaneously avoiding the excessive use of dredging sand. Therefore, the AVP method can lead to potential economic benefits and protect the natural environment, and it is a method worth considering. Moreover, the mathematical model for predicting consolidation settlement of the AVP method was proposed based on new mechanical assumptions, which can be applied as a reference for settlement prediction in relevant engineering, and the rationality has been verified through comparison with measured settlement results.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, and code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors would like to acknowledge the National Natural Science Foundation of China (NSFC) (No. 51908406) for their financial support.
References
Anda, R., H. Fu, J. Wang, H. Lei, X. Hu, Q. Ye, Y. Cai, and Z. Xie. 2020. “Effects of pressurizing timing on air-booster vacuum consolidation of dredged slurry.” Geotext. Geomembr. 48 (4): 491–503. https://doi.org/10.1016/j.geotexmem.2020.02.007.
Barron, R. A. 1948. “Consolidation of fine-grained soils by drain wells.” Trans. Am. Soc. Civ. Eng. 113 (1): 718–742. https://doi.org/10.1061/TACEAT.0006098.
Berry, P. L., and W. B. Wilkinson. 1969. “The radial consolidation of clay soils.” Géotechnique 19 (2): 253–284. https://doi.org/10.1680/geot.1969.19.2.253.
Cai, Y., Z. Xie, J. Wang, P. Wang, and X. Geng. 2018. “New approach of vacuum preloading with booster prefabricated vertical drains to improve deep marine clay strata.” Can. Geotech. J. 55 (10): 1359–1371. https://doi.org/10.1139/cgj-2017-0412.
Chai, J., J. P. Carter, and S. Hayashi. 2005. “Ground deformation induced by vacuum consolidation.” J. Geotech. Geoenviron. Eng. 131 (12): 1552–1561. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:12(1552).
Indraratna, B., C. Rujikiatkamjorn, P. Baral, and J. Ameratunga. 2019. “Performance of marine clay stabilised with vacuum pressure: Based on Queensland experience.” J. Rock Mech. Geotech. Eng. 11 (3): 598–611. https://doi.org/10.1016/j.jrmge.2018.11.002.
Indraratna, B., C. Rujikiatkamjorn, and I. Sathananthan. 2005a. “Radial consolidation of clay using compressibility indices and varying horizontal permeability.” Can. Geotech. J. 42 (5): 1330–1341. https://doi.org/10.1139/t05-052.
Indraratna, B., I. Sathananthan, C. Rujikiatkamjorn, and A. S. Balasubramaniam. 2005b. “Analytical and numerical modeling of soft soil stabilized by PVD incorporating vacuum preloading.” Int. J. Geomech. 5 (2): 114–124. https://doi.org/10.1061/(ASCE)1532-3641(2005)5:2(114).
Kjellman, W. 1952. “Consolidation of clayed soils by atmospheric pressure.” In Proc., Conf. on Soil Stabilization, 258–263. Boston: Massachusetts Institute of Technology.
Lei, H., Y. Hu, J. J. Liu, X. Liu, and C. Y. Li. 2021a. “Consolidation behavior of Tianjin dredged clay using two air-booster vacuum preloading methods.” J. Zhejiang Univ. Sci. A 22 (2): 147–164. https://doi.org/10.1631/jzus.A2000133.
Lei, H., X. Liu, P. Wang, J. Liu, and Y. Hu. 2021b. “Experimental investigation of influence of air-boost pressure and duration on air-boost vacuum preloading consolidation.” Int. J. Geomech. 21 (6): 04021088. https://doi.org/10.1061/(ASCE)GM.1943-5622.0002044.
Lei, H., Z. Qi, Z. Zhang, and G. Zheng. 2017. “New vacuum-preloading technique for ultrasoft-soil foundations using model tests.” J. Rock Mech. Geotech. Eng. 17 (9): 04017049. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000934.
Liu, J., H. Lei, G. Zheng, S. Feng, and M. S. Rahman. 2018. “Improved synchronous and alternate vacuum preloading method for newly dredged fills: Laboratory model study.” Int. J. Geomech. 18 (8): 04018086. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001220.
Liu, J., J. Li, H. Lei, G. Zheng, and Y. Jin. 2022. “Ground improvement of dredged fills with two improved vacuum preloading methods: Case study.” J. Geotech. Geoenviron. Eng. 148 (12): 05022008. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002922.
Lu, M., and J. Sun. 2022. “Analytical model for consolidation of soft ground improved by PVDs with air-boosted system.” Comput. Geotech. 151 (Feb): 104968. https://doi.org/10.1016/j.compgeo.2022.104968.
Lu, M., S. Wang, S. W. Sloan, D. Sheng, and K. 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.
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.
Rujikiatkamjorn, C., and B. Indraratna. 2014. “Environmental sustainability of soft soil improvement via vacuum and surcharge preloading.” In Geo-Congress, 3658–3665. Reston, VA: ASCE. https://doi.org/10.1061/9780784413272.354.
Shang, J. Q., M. Tang, and Z. Miao. 1998. “Vacuum preloading consolidation of reclaimed land: A case study.” Can. Geotech. J. 35 (5): 740–749. https://doi.org/10.1139/t98-039.
Shen, Y., Y. Liu, S. Geng, Y. Qi, S. Dong, X. Xin, J. Sun, and H. Zheng. 2021. “Consolidation theory of homogeneous multilayer treatment by air-boosted vacuum preloading.” Eur. J. Environ. Civ. Eng. 26 (12): 5634–5652. https://doi.org/10.1080/19648189.2021.1915389.
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. Rock Mech. Geotech. Eng. 142 (11): 06016012. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001516.
Wang, J., H. Fu, W. Zhang, J. Ni, X. Li, and Y. Cai. 2023. “Effect of pressurization frequency and duration on the consolidation of a dredged soil using air booster vacuum preloading combined with prefabricated horizontal drains.” Geotext. Geomembr. 51 (1): 209–218. https://doi.org/10.1016/j.geotexmem.2022.10.009.
Wu, Y., Z. Rong, Y. Lu, X. Zhang, H. Zhang, and Q. C. Tran. 2022. “Experiment-al study of PVD-improved dredged soil with vacuum preloading and air pressure.” Geotext. Geomembr. 50 (4): 668–676. https://doi.org/10.1016/j.geotexmem.2022.03.008.
Xie, L., Z. Liang, G. Feng, Y. Li, and T. Wu. 2022. “Improved analytical solution for air-boosted vacuum consolidation of saturated soil using eigenfunction expansion method.” Symmetry 14 (9): 1757. https://doi.org/10.3390/sym14091757.
Xie, Z., J. Wang, H. Fu, Y. Cai, Y. Zhang, and H. Jin. 2020. “Effect of pressurization positions on the consolidation of dredged slurry in air-booster vacuum preloading method.” Mar. Georesour. Geotechnol. 38 (1): 122–131. https://doi.org/10.1080/1064119X.2018.1563252.
Zheng, G., J. Liu, H. Lei, M. S. Rahman, and Z. Tan. 2017. “Improvement of very soft ground by a high-efficiency vacuum preloading method: A case study.” Mar. Georesour. Geotechnol. 35 (5): 631–642. https://doi.org/10.1080/1064119X.2016.1215363.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 150 • Issue 5 • May 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: May 9, 2023
Accepted: Nov 27, 2023
Published online: Feb 27, 2024
Published in print: May 1, 2024
Discussion open until: Jul 27, 2024
ASCE Technical Topics:
- Case studies
- Consolidated soils
- Design (by type)
- Engineering fundamentals
- Environmental engineering
- Foundation settlement
- Foundations
- Geomechanics
- Geotechnical engineering
- Load factors
- Mathematical models
- Methodology (by type)
- Models (by type)
- Pollution
- Preloading
- Research methods (by type)
- Soil dynamics
- Soil mechanics
- Soil pollution
- Soil properties
- Soil stabilization
- Soil treatment
- Soils (by type)
- Structural design
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.