# INNOVATIVE IMPLICIT FINITE DIFFERENCE SOLUTION TO TIME RATE OF SETTLEMENT IN CLAY

### AMIR W. AL-KHAFAJI

The primary consolidation process in clay involves changes in excess pore water pressure (EPWP) with time. The changes in the EPWP are related to permeability, void ratio, and boundary conditions. Closed-form solutions for simple initial EPWP have been published. Such solutions include simplifying assumptions and limited to few impractical initial EPWP distributions. Generally, the initial EPWP encountered in practice is complex, in which case, numerical methods are used. The finite differences and the finite element methods are the primary tools employed in the analysis of settlement behavior of fine-grained soils. Unfortunately, these methods suffer from three main problems: (1) they require evaluation of EPWP vectors at each time increment which results in a large number of calculations; (2) roundoff errors at each time increment; and (3) the solution for a given initial EPWP distribution is achieved at a predetermined integer time increment. An innovative explicit finite difference model is proposed that will permit any initial EPWP distribution, substantially reduces the number of calculations and roundoff errors.

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