settlement_of_shallow_foundations_on_granular_soils (Lutenegger ang DeGroot)

where:
z = layer thickness (in ft.)
Em'"' = maximum soil modulus (in ksf)
The value ofE""'"' the maximum soil elastic modulus which corresponds to a.strain level of 0.001%,
is obtained from:
where:
[4.19]
[ 4.20]
The strain parameter, A;, is then used to adjust the soil modulus, Em'"'' to give the "operational" soil
modulus using the chart provided in Figure 4.17. The soil modulus for calculating the settlement
of each layer is then determined from:
The settlement from each layer is calculated from:
[4.21]
Sj = ( qBIEJ'I'i
[4.22]
Total settlement of the compressible zone is then obtained from:
n
s=Es.
i = 1 '
[4.23]
4.5 Das (1983)
The general elastic expression for settlement presented in Section 4.1 is for the settlement
at the surface of a semi-infinite homogenous half-space. Das (1983) suggested a method to calculate
the elastic settlement of a footing on a finite thickness compressible layer (H < lOB) by subtracting
the settlement calculated for the same footing as if it were at a depth in the half space equal to the
depth of the bottom of the compressible layer from the settlement calculated from the general
elastic solution.
This method is performed as follows:
1 - Compute the settlement(s) of the footing on a semi-infinite
half space using Equation 4.1.
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