Erosion rate constant.

Initial and 1-year densities.

Initial and 1-year bulk shear strengths.

Consolidation coefficient.

Clay or sand.

New clay deposits form layers up to a specified initial thickness and then increase in

density and strength with increasing overburden pressure and age. Variation with

overburden occurs by increasing the layer type value by one for each additional layer

deposited above it. The original version of SED2D WES and all previous versions

of STUDH did not perform ongoing consolidation. Rather, the age was specified

and at the beginning of the simulation the parameters were computed. This strategy

worked well when simulations were always relatively short because of historical

limitations of computer resources. However, as computing power has evolved we

now have included active consolidation during the model simulation. The present

change in density with time is governed by the following equations:

ρ = ρ f - (ρ f - ρi )e- βt

where

ρ

=

time - varying characteristic of density

ρe

=

density at some reference end time

final ultimate density = 1000 kg/m3 default

ρf

=

=

starting time = zero

=

reference end time

=

time

β

=

consolidation coefficient, 1/sec

The consolidation coefficient β is computed from user input for initial density and

density at the reference time by solving Equation 21 for β.

1 ⎡

ρ - ρi ⎤

β =-

ln ⎢1 - e

⎥

⎣

⎦

The bulk shear strength, QS, of the deposits is related to the density by the

relationship

ln(QSi ) - ln(QS e )

α

= ⎜ ⎟ ⇒α =

ln(ρ i ) - ln(ρ e )

⎝ ⎠

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