Limits on a Common Approximation for Layered Consolidation Analysis

A widely used procedure for solving the problem of vertical consolidation of layers with different properties is to transform the thicknesses of the layers in proportion to the square root of their coefficients of consolidation. However, the Gray-Barber closed-form solution shows that this procedure is not correct except under a restrictive set of conditions. The transformation method should not be used. When solutions are needed for layered systems, the Gary-Barber solution or numerical methods should be employed.