settlement_of_shallow_foundations_on_granular_soils (Lutenegger ang DeGroot)

5.6.2 Barata (1973)
B arata also pointed out that the expression for settlement of plates on granular soils was
severely limited in application and that in many cases the results obtained from this extrapolation
would be in error. It was suggested that an expression based on the concepts suggested by Housel
(1929) and Burmister (1947) would be of more general applicability.
According to Housel (1929) the settlement of a square plate with side B = 2b on the surface
of the ground is given as:
s = n, + m, (PIA)
[5.116]
where:
s = settlement
n, & m, = characteristic coefficients of the ground
P =perimeter of the plate
A= area of the plate
Burmister (1947) adopted the theory of elasticity to Equation 5.116 to obtain expressions for n, and
m, as:
n, = (C')/C 8 (l-f! 2 )
m, = (E,')/4C( l-f!)
[5.117]
[5.118]
where:
E, = modulus of deformation at the ground surface
C =rate of modulus increase with depth (i.e. Ez = E, + Cz)
fl =Poison's ratio
C 5 = coefficient dependent on the shape and rigidity of the plate
Barata (1973) presented a series of charts for different values of C and for different plate
sizes, taking into account the initial modulus value, E, , and assuming Poisson's ratio equals 0.3.
The general relationship between the settlement of a plate with width equal to 0.3m (1ft) and any
size plate was thus expressed as:
s/s, =(BIB,) ((E, + CB,)/(E, + CB)) [5.119]
which may be restated as:
s/s, = (B/B,)(8) [5.120]
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