摘要：An iterative algorithm based on a full-Newton method for the estimation of the
saturated hydraulic conductivity k in the unsaturated zone from drainage
experiments is presented. The groundwater ow is assumed to be described by
Richards equation and the well-known van Genuchten constitutive model. The
cost functional used for the parameter optimization is dened as the L2-error
between the calculated pressure head values and the observed data at discrete
points in the soil prole during the drainage process. The derivative of
pressure head with respect to the parameter k is obtained as the solution of
a differential equation with appropriate boundary and initial conditions. A
Galerkin nite element procedure is used to obtain approximated solutions of
the two differential problems involved in each iteration: the direct problem
and the derivative of the functional. The algorithm was implemented in
one-dimensional domains and used to estimate k in layered soil using
synthetically generated data. Numerical examples show that the proposed
algorithm yields very good estimations of the saturated hydraulic
conductivity and becomes a promising method for in situ estimation of this
parameter.
