Abstract
The semi-analytical solutions to Fredlund and Hasan’s one-dimensional (1D) consolidation for unsaturated soils with a semi-permeable drainage boundary are presented. Two variables are introduced to transform the two coupled governing equations of pore-water and pore-air pressures into an equivalent set of partial differential equations (PDFs), which are easily solved by the Laplace transform method. Then, the pore-water pressure, pore-air pressure, and soil settlement are obtained in the Laplace domain. The Crump method is adopted to perform the inverse Laplace transform in order to obtain the semi-analytical solutions in the time domain. It is shown that the proposed solutions are more applicable to various types of boundary conditions and agree well with the existing solutions from the literature. Several numerical examples are provided to investigate the consolidation behavior of an unsaturated single-layer soil with single, double, mixed, and semi-permeable drainage boundaries. The changes in the pore-air and pore-water pressures and the soil settlement with the time factor at different values of the semi-permeable drainage boundary parameters are illustrated. In addition, parametric studies are con- ducted on the pore-air and pore-water pressures at different ratios (the air permeability coefficient to the water permeability coefficient) and depths.
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Abbreviations
- C a :
-
interactive constant with respect to the air phase
- C w :
-
interactive constant with respect to the water phase
- C av :
-
coefficient of volume change with respect to the air phase
- C wv :
-
coefficient of the volume change with respect to the water phase
- C a σ :
-
consolidation coefficient for the air phase
- C w σ :
-
consolidation coefficient for the water phase
- g :
-
gravitational acceleration
- h :
-
soil layer thickness
- h 0 :
-
top boundary thickness
- k a :
-
coefficient of the air permeability
- k w :
-
coefficient of the water permeability
- k a0 :
-
coefficient of the air permeability at the top boundary
- k w0 :
-
coefficient of the water permeability at the top boundary
- M :
-
molecular mass of air
- m a1k :
-
coefficient of the air volume change with respect to a change in (σ - ua)
- m a2 :
-
coefficient of the air volume change with respect to a change in (u a − u w)
- m w1k :
-
coefficient of the water volume change with respect to a change in (σ − u a)
- m w2 :
-
coefficient of the water volume change with respect to a change in (u a − u w)
- n 0 :
-
initial porosity
- q 0 :
-
initial surcharge
- R :
-
universal gas constant
- Q(s):
-
result of the Laplace transform of \(\frac{{{\partial _q}\left( t \right)}}{{\partial t}}\)
- R a :
-
parameter of the semi-permeable drainage for the air at the top bound- ary
- R w :
-
parameter of the semi-permeable drainage for the water at the top boundary
- S r0 :
-
initial degree of the saturation
- T :
-
absolute temperature
- t :
-
time
- u a :
-
pore-air pressure
- u atm :
-
atmospheric pressure
- \(\overline u _a^0\) :
-
absolute pore-air pressure
- u 0a :
-
initial excess pore-air pressure
- u w :
-
pore-water pressure
- u 0w :
-
initial excess pore-water pressure
- w :
-
settlement
- w*:
-
normalized settlement
- z :
-
depth
- γ w :
-
unit weight of water
- ε v :
-
volumetric strain
References
Xie, K. H., Xie, X. Y., and Gao, X. Theory of one dimensional consolidation of two-layered soil with partially drained boundaries. Computers & Geotechnics, 24, 265–278 (1999)
Gray, H. Simultaneous consolidation of contiguous layers of unlike compressible soils. Transactions, ASCE, 110, 1327–1356 (1945)
Schiffman, R. L. and Stein, J. R. One-dimensional consolidation of layered systems. Journal of the Soil Mechanics and Foundations Division, 96, 1499–1504 (1970)
Scott, R. F. Principles of Soil Mechanics, Addison-Wesley Pub. Co., Boston (1963)
Biot, M. A. General theory of three-dimensional consolidation. Journal of Applied Physics, 12, 155–164 (1941)
Barden, L. Consolidation of compacted and unsaturated clays. Geotechnique, 15, 267–286 (1965)
Fredlund, D. G. and Hasan, J. U. One-dimensional consolidation theory: unsaturated soils. Canadian Geotechnical Journal, 17, 521–531 (1979)
Dakshanamurthy, V., Fredlund, D. G., and Rahardjo, H. Coupled three-dimensional consolidation theory of unsaturated porous media. Proceedings of 5th International Conference on Expansive Soils, Adelaide, 99–103 (1984)
Fredlund, D. G., Rahardjo, H., and Fredlund, M. D. Unsaturated Soil Mechanics in Engineering Practice, John Wiley & Sons, Hoboken (2012)
Qin, A. F., Chen, G. J., Tan, Y. W., and Sun, D. A. Analytical solution to one dimensional consolidation in unsaturated soils. Applied Mathematics and Mechanics (English Edition), 29(10), 1329–1340 (2008) DOI 10.1007/s10483-008-1008-x
Qin, A. F., Sun, D. A., and Tan, Y. W. Semi-analytical solution to one-dimensional consolidation in unsaturated soils. Applied Mathematics and Mechanics (English Edition), 31(2), 215–226 (2010) DOI 10.1007/s10483-010-0209-9
Shan, Z. D., Ling, D. S., and Ding, H. J. Exact solutions for one-dimensional consolidation of single-layer unsaturated soil. International Journal for Numerical and Analytical Methods in Geomechanics, 36, 708–722 (2012)
Shan, Z. D., Ling, D. S., and Ding, H. J. Analytical solution for 1D consolidation of unsaturated soil with mixed boundary condition. Journal of Zhejiang University-Science A, 14, 61–70 (2013)
Zhou, W. H., Zhao, L. S., and Li, X. B. A simple analytical solution to one-dimensional consolidation for unsaturated soils. International Journal for Numerical and Analytical Methods in Geomechanics, 38, 794–810 (2014)
Zhou, W. H. and Zhao, L. S. One-dimensional consolidation of unsaturated soil subjected to time-dependent loading with various initial and boundary conditions. International Journal of Geomechanics, 14, 291–301 (2014)
Ho, L. and Fatahi, B. One-dimensional consolidation analysis of unsaturated soils subjected to time-dependent loading. International Journal of Geomechanics, 16, 04015052 (2015)
Ho, L. and Fatahi, B. Axisymmetric consolidation in unsaturated soil deposit subjected to timedependent loadings. International Journal of Geomechanics, 17, 04016046 (2016)
Ho, L., Fatahi, B., and Khabbaz, H. A closed form analytical solution for two-dimensional plane strain consolidation of unsaturated soil stratum. International Journal for Numerical and Analytical Methods in Geomechanics, 39, 1665–1692 (2015)
Crump, K. S. Numerical inversion of Laplace transforms using a Fourier series approximation. Journal of the Association for Computing Machinery, 23, 89–96 (1976)
Wang, L., Sun, D. A., and Qin, A. F. General semi-analytical solutions to one-dimensional consolidation for unsaturated soils. Applied Mathematics and Mechanics (English Edition), 38(6), 831–850 (2017) DOI 10.1007/s10483-017-2209-8
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Project supported by the National Natural Science Foundation of China (Nos. 41630633 and 11672172)
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Wang, L., Sun, D. & Xu, Y. Semi-analytical solutions to one-dimensional consolidation for unsaturated soils with semi-permeable drainage boundary. Appl. Math. Mech.-Engl. Ed. 38, 1439–1458 (2017). https://doi.org/10.1007/s10483-017-2243-6
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DOI: https://doi.org/10.1007/s10483-017-2243-6
Key words
- semi-analytical solution
- unsaturated soil
- one-dimensional (1D) consolidation
- semi-permeable drainage boundary
- Laplace transform