Lateral displacement of soft ground under vacuum pressure and surcharge load

Abstract

Surcharge load (e.g. embankment fill) will induce settlement and outward lateral displacement, while vacuum pressure will induce settlement and inward lateral displacement of a ground. Ideally, combination of surcharge load and vacuum pressure can reduce or minimize the lateral displacement. Laboratory large scale model (length: 1.50 m, width: ~0.62 m, height: 0.85 m) tests and finite element analyses (FEA) were conducted to investigate the main influencing factors on lateral displacement of a soft clayey ground under the combination of vacuum pressure and surcharge load. For the conditions investigated, the results indicate that the outward lateral displacement increases with the increase of the ratio of surcharge load to vacuum pressure (RL) and the loading rate of the surcharge load (LR). Also, it is shown that for a given RL and LR condition, lateral displacement reduces with the increase of the initial undrained shear strength (S_u) of the ground. To predict the lateral displacement of a ground under the combination of surcharge load and vacuum pressure, the loading conditions in terms of RL and LR, and S_u value of the ground have to be considered.

Keywords

vacuum consolidation / lateral displacement / PVD / finite element analysis / surcharge load

References

[1] Chai J C, Carter J P, Hayashi S. Vacuum consolidation and its combination with embankment loading. Canadian Geotechnical Journal, 2006, 43(10): 985-996

[2] Chu J, Yan S W, Yang H. Soil improvement by the vacuum preloading method for an oil storage station. Géotechnique, 2000, 50(6): 625-632

[3] Indraratna B N, Rujikiatkamjorn C. McIntosh G, Balasubramaniam A S.Vacuum consolidation effects on lateral yield of soft clays as applied to road and railway embankment. In: Proceedings of the International Symposium on Geotechnical Engineering, Ground Improvement and Geosynthetics for Human Security and Environmental Preservation. Bangkok, Thailand, 2007, 31-62

[4] Shang J Q, Tang M, Miao Z. Vacuum preloading consolidation of reclaimed land: a case study. Canadian Geotechnical Journal, 1998, 35(4-6): 740-749

[5] Chai J C, Miura N, Bergado D T. Preloading clayey deposit by vacuum pressure with cap-drain: analyses versus performance. Geotextiles and Geomembranes, 2008, 26(3): 220-230

[6] Fujii A, Tanaka H, Tsuruya H, Shinsha H. Field test on vacuum consolidation method by expecting upper clay layer as sealing up material. In: Proceedings of the Symposium on Recent Development about Clayey Deposit—From Microstructure to Soft Ground Improvement. Japanese Geotechnical Society, 2002, 269-274 (in Japanese).

[7] Britto A M, Gunn M J. Critical State Soil Mechanics via Finite Elements. London: McGraw Hill,1987

[8] Chai J C, Miura N, Sakajo S, Bergado D T. Behavior of vertical drain improved subsoil under embankment loading. Soils and Foundations, Tokyo, 1995, 35(4): 49-61

[9] Roscoe K H, Burland J B. On the generalized stress-strain behavior of ‘wet’ clay. In: Heyman J, Leckie F A, eds. Engineering plasticity, Cambridge: Cambridge University Press, 1968, 535-609

[10] Taylor D W. Fundamentals of Soil Mechanics. New York: Wiley, 1948

[11] Chai, J C, Miura N, Kirekawa T, Hino T.Optimum PVD installation depth for two-way drainage deposit. Geomechanics and Engineering, An International Journal, 2009, 1(3): 179-192

[12] Japan Road Association. Guidelines and counter-measure for road and earthworks construction. Japan Road Association, Japan, 1986 (in Japanese)

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg