ANALYSIS OF CONSOLIDATION OF FREE DRAINAGE WELL IN UNSATURATED SOIL WITH VARIABLE PERMEABILITY COEFFICIENT WITHIN SMEAR ZONE

The previous research theory of consolidation of unsaturated soil free drainage well foundation, both the permeability coefficient within the searched area and the non-searched area are considered equal. This assumption is not consistent with the actual engineering. The permeability coefficient can be variable within the smear zone in this paper. It gives the analysis of the regularity in pressure of excess pore water and air. It is based on Fredlund one-dimensional consolidation theory, Darcy's law and the law of Fick. It examines finite thickness on the linear elastic unsaturated soil with sand drain foundation, and large area uniform transient load conditions. The change of permeability coefficient is considered in smear zone soil. It uses Laplace transformation and the introduction of Bessel function. It is accomplished by means crump Laplace inverse transformation. The excess pore-air and pore-water pressure with semi-analytical solutions are got for unsaturated soil free drain wells. It calculates typical examples in different radius, smear zone radius and under the condition of different smear zone, and obtains air excess pore pressure and excess pore water pressure with the change rule of the time. The dissipation rates of air excess pore pressure and excess pore water pressure are much slower when the smear effect is considered. The greater the smear zone radius and the higher level of smear, then much slower and the more quickly conversely. This study enriches the theory of consolidation of unsaturated soil free drainage wells. The characteristics of the unsaturated soil consolidation of sand drain has certain reference value in engineering.