D-R-A-F-T
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:
Equation 21
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
=
to
=
starting time = zero
=
reference end time
te
t
=
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.
Equation 22
1 ⎡
ρ - ρi ⎤
β =-
ln ⎢1 - e
⎥
te ⎢ ρ f - ρi ⎥
⎣
⎦
The bulk shear strength, QS, of the deposits is related to the density by the
relationship
Equation 23
ln(QSi ) - ln(QS e )
α
QS e ⎛ ρ e ⎞
= ⎜ ⎟ ⇒α =
QSi ⎜ ρ i ⎟
ln(ρ i ) - ln(ρ e )
⎝ ⎠
Conceptual Program Design 15
Users Guide To SED2D-WES
Previous Page
