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SUMMARY This paper introduces an exact analytical solution for governing flow equations for one-dimensional consolidation in unsaturated soil stratum using the techniques of eigenfunction expansion and Laplace transformation. The homogeneous boundary conditions adopted in this study are as follows: (i) a one-way drainage system of homogenous soils, in which the top surface is considered as permeable to air and water, whereas the base is an impervious bedrock; and (ii) a two-way drainage system where both soil ends allow free dissipation of pore-air and pore-water pressures. In addition, the analytical development adopts initial conditions capturing both uniform and linear distributions of the initial excess pore pressures within the soil stratum. Eigenfunctions and eigenvalues are parts of the general solution and can be obtained based on the proposed boundary conditions. Besides, the Laplace transform method is adopted to solve the first-order differential equations. Once equations with transformed domain are all obtained, the final solutions, which are proposed to be functions of time and depth, can be achieved by taking an inverse Laplace transform. To verify the proposed solution, two worked examples are provided to present the consolidation characteristics of unsaturated soils based on the proposed method. The validation of the recent results against other existing analytical solutions is graphically demonstrated. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ground improvement using stone columns is one of the most suitable methods for deformation control of soft soils. The use of stone columns can improve the bearing capacity, reduce settlement, accelerate consolidation process and enhance slope stability as well as resistance to liquefaction. Settlement prediction of the ground influenced by the large stiffness difference between the columns and the surrounding soil and the induced arching is discussed in this paper. Plate load test is one of the common methods to be used for quality control of stone column reinforced ground. The test results can be used to back calculate some of the design parameters of the stone column. A finite element based procedure to estimate the Young's modulus and dilation angle of stone column material using plate load test results is proposed. The employed finite element model is axisymmetric and suitable for a cylindrical stone column. The field measurements after calibration have been in good agreement with numerical results for predicting deformations. The procedure developed in this study can be adopted by practicing engineers to estimate the Young's modulus and dilation angle of stone columns by conducting a plate load test. [ABSTRACT FROM AUTHOR]