Similar articles

Abstract: In actual engineering practice, the stress increment within a composite foundation caused by external loads may vary simultaneously with depth and time. In addition, column installation always leads to a decay of soil permeability towards the column. However, almost none of the consolidation theories for composite foundation comprehensively consider these factors until now. For this reason, a stress increment due to external loads changing simultaneously with time and depth was incorporated into the analysis, and three possible variation patterns of soil’s horizontal permeability coefficient were considered to account for the detrimental influence of column installation. These three patterns included a constant distribution pattern (Pattern I), a linear distribution pattern (Pattern II), and a parabolic distribution pattern (Pattern III). Solutions were obtained for the average excess pore water pressures and the average degree of consolidation respectively. Then several special cases were discussed in detail based on the general solution obtained. Finally, comparisons were made, and the results show that the present solution is the most general rigorous solution in the literature, and it can be broken down into a number of previous solutions. The consolidation rate is accelerated with the increase in the value of the top to the bottom stress ratio. The consolidation rate calculated by the solution for Pattern I is less than that for Pattern II, which in turn is less than that for Pattern III.

[1]Balaam, N.P., Booker, J.R., 1981. Analysis of rigid rafts supported by granular piles. International Journal for Numerical and Analytical Method in Geomechanics, 5(4):379-403.

[2]Basu, D., Prezzi, M., 2007. Effect of the smear and transition zones around PVD installed in a triangular pattern on the rate of soil consolidation. International Journal of Geomechanics, 7(1):34-43.

[3]Castro, J., Sagaseta, C., 2009. Consolidation around stone columns: influence of column deformation. International Journal for Numerical and Analytical Methods in Geomechanics, 33(7):851-877.

[4]Chai, J.C., Miura, N., 1999. Investigation of factors affecting vertical drain behavior. Journal of Geotechnical and Geoenvironmental Engineering, 125(3):216-226.

[5]Han, J., Ye, S.L., 2002. A theoretical solution for consolidation rates of stone column-reinforced foundations accounting for smear and well resistance effects. International Journal of Geomechanics, 2(2):135-151.

[6]Indraratna, B., Redana, I.W., 1998. Laboratory determination of smear zone due to vertical drain installation. Journal of Geotechnical and Geoenvironmental Engineering, 124(2):180-184.

[7]Leo, C.J., 2004. Equal strain consolidation by vertical drains. Journal of Geotechnical and Geoenvironmental Engineering, 130(3):316-327.

[8]Lu, M.M., Xie, K.H., Guo, B., 2010. Consolidation theory for a composite foundation considering radial and vertical flows within the column and the variation of soil permeability within the disturbed soil zone. Canadian Geotechnical Journal, 47(2):207-217.

[9]Sharma, J.S., Xiao, D., 2000. Characterization of a smear zone around vertical drains by large-scale laboratory tests. Canadian Geotechnical Journal, 37(6):1265-1271.

[10]Walker, R., Indraratna, B., 2006. Vertical drain consolidation with parabolic distribution of permeability in smear zone. Journal of Geotechnical and Geoenvironmental Engineering, 132(7):937-941.

[11]Walker, R., Indraratna, B., 2007. Vertical drain consolidation with overlapping smear zones. Geotechnique, 57(5):463-467.

[12]Wang, R.C., Xie, K.H., Guan, S.H., 2002. Analytical solutions for consolidation of composite ground with granular columns under time-dependent loading. Journal of Zhejiang University (Engineering Science), 36(1):12-16 (in Chinese).

[13]Wang, X.S., Jiao, J.J., 2004. Analysis of soil consolidation by vertical drains with double porosity model. International Journal for Numerical and Analytical Method in Geomechanics, 28(14):1385-1400.

[14]Xie, K.H., Lu, M.M., Liu, G.B., 2009. Equal strain consolidation for stone-column reinforced foundation. International Journal for Numerical and Analytical Methods in Geomechanics, 33(15):1721-1735.

[15]Zhang, Y.G., Xie, K.H., Wang, Z., 2006. Consolidation Analysis of Composite Ground Improved by Granular Columns Considering Variation of Permeability Coefficient of Soil. Proceedings of Sessions of Geo Shanghai, Ground Modification and Seismic Mitigation, ASCE, Shanghai, China, 152:135-142.

[16]Zhu, G.F., Yin, J.H., 2004. Consolidation analysis of soil with vertical and horizontal drainage under ramp loading considering smear effects. Geotextiles and Geomembranes, 22(1-2):63-74.