DOI QR코드

DOI QR Code

Field instrumentation and settlement prediction of ground treated with straight-line vacuum preloading

  • Lei, Huayang (Department of Civil Engineering, Tianjin University) ;
  • Feng, Shuangxi (Department of Civil Engineering, Tianjin University) ;
  • Wang, Lei (Department of Civil Engineering, Tianjin University) ;
  • Jin, Yawei (Jiangsu Xintai Geotechnical Technology Co. Ltd)
  • 투고 : 2018.07.31
  • 심사 : 2019.11.28
  • 발행 : 2019.12.10

초록

The vacuum preloading method has been used in many countries for ground improvement and land reclamation works. A sand cushion is required as a horizontal drainage channel for conventional vacuum preloading. In terms of the dredged-fill foundation soil, the treatment effect of the conventional vacuum preloading method is poor, particularly in Tianjin, China, where a shortage of sand exists. To solve this problem, straight-line vacuum preloading without sand is widely adopted in engineering practice to improve the foundation soil. Based on the engineering properties of dredged fill in Lingang City, Tianjin, this paper presents field instrumentation in five sections and analyzes the effect of a prefabricated vertical drain (PVD) layout and a vacuum pumping method on the soft soil ground treatment. Through the arrangement of pore water pressure gauges, settlement marks and vane shear tests, the settlement, pore water pressure and subsoil bearing capacity are analyzed to evaluate the effect of the ground treatment. This study demonstrates that straight-line vacuum preloading without sand can be suitable for areas with a high water content. Furthermore, the consolidation settlement and consolidation degree system is developed based on the grey model to predict the consolidation settlement and consolidation degree under vacuum preloading; the validity of the system is also verified.

키워드

과제정보

연구 과제 주관 기관 : National Natural Science Foundation of China (NSFC), Tianjin University, China Scholarship Council (CSC)

The authors acknowledge the National Key Research and Development Program of China (Grant No. 2017YFC0805402), the National Natural Science Foundation of China (NSFC) (Grant No. 51578371), the Open Project of State Key Laboratory of Disaster Reduction in Civil Engineering (Grant No. SLDRCE17-01), the Tianjin Construction Commission Science and Technology Project (Grant No. 2017E6-0015), Incentive Fund for Overseas Visits of Doctoral Students of Tianjin University in 2019 (070-0903077101), and China Scholarship Council (CSC. 201906250153) for their financial support.

참고문헌

  1. Barron, R.A., Lane, K.S., Keene, P. and Kjellman, W. (1948), "Consolidation of fine-grained soils by drain wells", Jap. Geotech. Soc. Spec. Publ., 74(118), 324-360.
  2. Cai, Y., Xie, Z, Wang, J., Wang, P. and Geng, X. (2018), "A new approach of vacuum preloading with booster PVDs to improve deep marine clay strata", Can. Geotech. J., 55(10), 1359-1371. https://doi.org/10.1139/cgj-2017-0412.
  3. Deng, J. (1994), "Modeling for satisfactory non-equigap GM(1,1)", J. Grey Syst., 6(2), 75-86.
  4. Indraratna, B., Rujikiatkamjorn, C., Ameratunga, J. and Boyle, P. (2011), "Performance and prediction of vacuum combined surcharge consolidation at port of Brisbane", J. Geotech. Geoenviron. Eng., 137(11), 1009-1018. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000519.
  5. Khan, A.Q. and Mesri, G. (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.
  6. Le, C., Xu, C., Jin, Y.W. and Yang, Y. (2013), "Application of improved vacuum preloading method in Tianjin Lingang Industrial Zone", New Front. Eng. Geol. Environ., 9(7), 279-284. https://doi.org/10.1007/978-3-642-31671-5_51.
  7. Lei, H., Qi, Z., Zhang, Z. and Zheng, G. (2017). "A new vacuum preloading technique for ultra-soft soil foundations using model tests", Int. J. Geomech., 17(9), 04017049. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000934.
  8. Lei, H., Wang, X., Chen, L., Huang, M. and Han, J. (2016), "Compression characteristics of ultra-soft clays subjected to simulated staged preloading", KSCE J. Civ. Eng., 20(2), 718-728. https://doi.org/10.1007/s12205-015-0343-y.
  9. Liu, G. and Feng, S.X. (2014), "Prediction and correlation factor analysis of pipeline settlement in construction of deep foundation pit", Architect. Technol., 45(7), 644-646.
  10. Liu, H., Xiang, Y. and Nguyen, H (2013), "A multivariable grey model based on optimized background value and its application to subgrade settlement prediction", Appl. Mech. Mater., 256-259(1), 1721-1725. https://doi.org/10.4028/www.scientific.net/AMM.256-259.1721.
  11. Liu, J., Lei, H., Zheng, G., Feng, S. and Rahman, M.S. (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.
  12. Liu, J., Lei, H., Zheng, G., Zhou, H. and Zhang, X. (2017), "Laboratory model study of newly deposited dredger fills using improved multiple-vacuum preloading technique", J. Rock Mech. Geotech. Eng., 9(5), 924-935. https://doi.org/10.1016/j.jrmge.2017.03.003.
  13. Liu, S., Zhang, D., Du, G. and Han, W. (2016), "A new combined vacuum preloading with pneumatic fracturing method for soft ground improvement", Procedia Eng., 143, 454-461. https://doi.org/10.1016/j.proeng.2016.06.057.
  14. Mesri, G. and Khan, A.Q. (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.
  15. Ministry of Transport of the People's Republic of China. (2009), Technical Specification for Vacuum Preloading Technique to Improve Soft Soils (JTS_147-2-2009), China Communications Press, Beijing, China.
  16. Ministry of Water Resources of the People's Republic of China. (2019), Specification of Soil Test (GB/T50123-2019), China Communications Press, Beijing, China.
  17. Ministry of Water Resources of the People's Republic of China. (2003), Code for in-situ Measurement of Railway Engineering Geology (TB10041-2003), China Communications Press, Beijing, China.
  18. Quang, N. and Giao, P. (2014), "Improvement of soft clay at a site in the mekong delta by vacuum preloading", Geomech. Eng., 6(5), 419-436. http://dx.doi.org/10.12989/gae.2014.6.4.419.
  19. Rujikiatkamjorn. C., Indraratna. B. and Chu. J. (2008), "2D and 3D numerical modeling of combined surcharge and vacuum preloading with vertical drains", Int. J. Geomech., 8(2), 144-156. https://doi.org/10.1061/(ASCE)1532-3641(2008)8:2(144).
  20. Saowapakpiboon, J., Bergado, D.T., Voottipruex, P., Lam, L.G. and Nakakuma, K. (2011), "PVD improvement combined with surcharge and vacuum preloading including simulations", Geotext. Geomembr., 29(1), 74-82. https://doi.org/10.1016/j.geotexmem.2010.06.008.
  21. Shahin, M.A., Jaksa, M.B. and Maier, H.R. (2005), "Neural network based stochastic design charts for settlement prediction", Can. Geotech. J., 42(1), 110-120. https://doi.org/10.1139/t04-096.
  22. Song, Y. and Kim, T. (2004), "Improvement of estuarine marine clays for coastal reclamation using vacuum-applied consolidation method", Ocean Eng., 31(16), 1999-2010. https://doi.org/10.1016/j.oceaneng.2004.05.004
  23. Terzaghi, K. (1925), "Principles of soil mechanics, IV-settlement and consolidation of clay", Eng. Newsrec., 95, 874-878.
  24. Tu, H., Xu, Y. and Xie, L. (2014), "Mechanism and numerical analysis of effect of air injection on vacuum preloading for weak foundation improvement", Rock Soil Mech., 35(s2), 600-606.
  25. Wang, J., Ma, J., Liu, F., Mi, W., Cai, Y. and Fu, H. (2016), "Experimental study on the improvement of marine clay slurry by electroosmosis-vacuum preloading", Geotext. Geomembr., 44(4), 615-622. https://doi.org/10.1016/j.geotexmem.2016.03.004.
  26. Wang, Q. (2015), "Application of vacuum preloading technique of water vapor separation in ultra-thick sludge soft foundation treatment", Sci. Technol. Ports., 50(9), 8-11.
  27. Wu, L., Wang, X. and Liu, Z. (2009), "Several calculation methods of consolidation degree during soft soil treatment by preloading method", Soil Eng. Found., 23(4), 66-68. https://doi.org/10.3969/j.issn.1004-3152.2009.04.020
  28. Wu, Y., Kong G. and Lu, Y. (2017), "Experimental study on vacuum preloading with flocculation for solid-liquid separation in waste slurry", Geomech. Eng., 13(2), 319-331. https://doi.org/10.12989/gae.2017.13.2.319.
  29. Xu, N. and Dang, Y. (2015), "An optimized grey GM (2,1) model and forecasting of highway subgrade settlement", Math. Prob. Eng., 2015(1), 1-6. http://dx.doi.org/10.1155/2015/606707.
  30. Yeung, A.T., So, S.T., Kwong, A.K., Tham, L.G. and Zhao, W.B. (2009), "Field-scale constructability evaluation of underwater vacuum preloading", Geomech. Geoeng., 4(3), 245-252. https://doi.org/10.1080/17486020903171382.
  31. You, J. (2006), "Programming of gray model in traffic volume forecast based on visual basic and microsoft excel", Comput. Commun., 42(4), 611-614.
  32. Zeng, F., Chen, X., Wang, J., Yan, J. and Guo, H. (2012), "Application of grey model method to vacuum preloading settlement and consolidation degree prediction", J. Jiangxi Univ. Sci. Technol., 12(3), 23-26.
  33. Zeng, G. and Yang, X. (1959), "Settlement analysis of sand well foundation", J. Zhejiang Univ., 4(3), 38-76. https://doi.org/10.1139/cgj-2018-0572.
  34. Zhu, S. and Miao, Z. (2002), "Recent development and improvement of vacuum preloading method for improving soft soil", Proc. Inst. Civ. Eng. Ground Improv., 6(2), 79-83. https://doi.org/10.1680/grim.2002.6.2.79.

피인용 문헌

  1. Shallow ground treatment by a combined air booster and straight-line vacuum preloading method: A case study vol.24, pp.2, 2019, https://doi.org/10.12989/gae.2021.24.2.129