SEEP/W Chapter 4: Material Properties
4.13 Soil material database
It can sometimes be difficult to obtain the appropriate input parameters or
functions that are required for seepage analyses. SEEP/W has various function
estimation techniques built into the software and also has a library file, included in
the examples folder, which contains soil property functions for 24 different soils. A
detailed description of these soils is included in the appendix of this book, while a
general overview of the soils is included below in Table 4-2.
The sample functions and estimation techniques are provided to help you get
started using the software and to help you understand the significance of material
property functions in seepage analysis. If you are unfamiliar with these types of
functions, looking through the example file will help you learn what an
appropriately shaped function looks like and comparison of the functions will give
some insight as to how the functions can vary for different types of materials.
Utilizing the estimation techniques and sample functions can be very useful during
the early stages of analysis when you are trying to understand the flow processes
for your project and to identify critical issues and areas within a flow regime. If it
appears that the analysis is going to be very sensitive to the material property
functions, then it may be necessary to more accurately quantify the soil that is
being modeled. It may also become necessary to conduct a sensitivity analysis to
ensure that your understanding of the material property functions is sufficient to
analyze the results.
The function library can be found in the examples folder under the file names
GeoStudio Database m-sec-kPa-C-J-kN.gsz and SEEP/W Database ft-hour-
PSF-F-BTU-lb.gsz, which present the functions in terms of metric (SI) units and
imperial (English) units respectively. The information provided for the first
seventeen soils include measured grain-size distribution curves, measured
volumetric water content functions and predicted hydraulic conductivity functions
developed using a measured saturated hydraulic conductivity and one of the three
predictive methods built into SEEP/W. The last seven functions (18-24 inclusive)
do not have grain-size distributions available, but are described by volumetric
water content functions taken from published literature. The hydraulic conductivity
functions for these materials have also been predicted using a measured saturated
hydraulic conductivity value. In some cases, the hydraulic conductivity functions
were adjusted slightly from the estimated data points in order to create a smooth
function.
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Chapter 4: Material Properties SEEP/W
The functions presented in these files can be imported into your own project files
and then modified as necessary to suit your given situation. For example, you can
import a function that has properties similar to the soils you are trying to model.
The functions can then be adjusted as necessary to increase their applicability to
your situation. Another benefit of the function library is the ability you now have
to compare your grain-size distribution curves to those in the function library and
thereby select material property functions that may represent soils found on site.
These example functions are provided to help you define functions when you do
not have any other data. As discussed earlier in this chapter, using an approximate
function leads to more realistic results than using a single-value function when the
problem involves saturated / unsaturated flow.
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SEEP/W Chapter 4: Material Properties
Table 4-2 Table of sample soil properties in database
# Soil Name Ksat Ksat K - Function Por AEV AEV D10 D60
(m/s) (ft/s) Estimation (n) (kPa) (psf) (mm) (mm)
Method
Uniform Fine
1 2.15E-05 7.05E-05 Fredlund et al. 0.30 2 42 0.18 0.4
Sand #1
Uniform Fine
2 1.13E-06 3.71E-06 Fredlund et al. 0.38 1 21 0.07 0.4
Sand #2
3 Sandy Loam 5.83E-06 1.91E-05 Green and Corey 0.38 6 125 0.06 0.3
4 Very Fine Sand 2.00E-08 6.56E-08 Green and Corey 0.42 3 63 0.55 0.15
Sandy Silt
5 4.80E-07 1.57E-06 Green and Corey 0.45 10 209 0.001 0.09
(Tails)
6 Silty Sand 5.00E-07 1.64E-06 Green and Corey 0.51 12 251 0.008 0.07
7 Well-graded 1.00E-07 3.28E-07 Fredlund et al. 0.41 15 313 0.005 16.1
8 Well-graded #2 1.50E-08 4.92E-08 Green and Corey 0.40 50 1045 n/a 6.7
9 Silt #2 1.00E-06 3.28E-06 Green and Corey 0.44 10 209 0.006 0.05
Glacial Till
10 5.00E-06 1.64E-05 Green and Corey 0.30 8 167 0.002 0.07
(Uncompact)
Glacial Till
11 1.00E-07 3.28E-07 Green and Corey 0.23 20 418 0.002 0.07
(Compacted)
12 Silt Loam 7.00E-07 2.30E-06 Green and Corey 0.45 15 313 0.002 0.026
13 Sandy Silty Clay 1.40E-07 4.59E-07 Green and Corey 0.42 50 1045 0.002 0.026
Silty Clay (Fine
14 3.00E-08 9.84E-08 Green and Corey 0.50 40 836 0.001 0.015
Tails)
15 Uniform Silt 1.00E-08 3.28E-07 Green and Corey 0.49 8 167 0.003 0.013
16 Clay/Silt 2.50E-08 8.20E-08 Fredlund et al. 0.38 10 209 <0.001 0.01
Well-graded #3
17 7.00E-10 2.30E-09 van Genuchten 0.35 43 898 <0.001 0.3
(high clay)
18 Uniform Sand 1.00E-04 3.28E-04 Green and Corey 0.35 3 63 0.1 n/a
19 Sand 5.40E-05 1.77E-04 Green and Corey 0.39 6 125 n/a n/a
20 Fine Sand 4.30E-06 1.41E-05 Green and Corey 0.35 4 84 0.093 n/a
21 Silt 2.50E-07 8.20E-07 Green and Corey 0.38 20 418 n/a n/a
22 Silt (Tailings) 5.80E-08 1.90E-07 Green and Corey 0.39 10 209 n/a n/a
Sandy Clayey
23 1.50E-08 4.92E-08 Green and Corey 0.35 15 313 n/a n/a
Silt
24 Clayey Silt 8.40E-09 2.76E-08 Green and Corey 0.41 25 522 0.003 n/a
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