117
Honour Lectures /
Conférences honorifiques
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
a. LOAD TEST SET UP
Settlement
Beam
LVDT Jack
Load cell
Inclinometer
casings
Drilled shaft
(Concrete+Bars)
Steel
plates
CLAY
SHALE
Dywidag bars
only No concrete
SAND
8.5 m
0.5B B
2B
B
15 m
2.7 m
2.7 m
10.7 m
7.6 m
Telltates
b.
PRESSUREMETER-LIKE LATERAL
DEFORMATION FROM INCLINOMETER
Figure 15. Analogy between the soil deformation under a
shallow foundation and around a pressuremeter expansion test
Shape
/
0.8 0.2
L B
B
f
L
(43)
Eccentricity
1 0.33
e
e
f
B
center
(44)
Eccentricity
0.5
1
e
e
f
B
edge
(45)
Inclination
2
1
90
f
center
(46)
Inclination
0.5
1
360
f
edge
(47)
Near 3/1 slope
0.1
,
0.8 1
d
d
f
B
(48)
Near 2/1 slope
0.15
,
0.7 1
d
d
f
B
(49)
Where B is the width of the footing, L its length, e the load
eccentricity, δ
the load inclination in degrees, and d the
horizontal distance from the slope-side edge of the footing to
the slope crest.
The shape of the Γ function indicates that at larger strain
levels the need to correct the PMT curve is minimal. Indeed for
s/B larger than 0.03, the mean value of Γ is constant and equal
to about 1.5. For values of s/B smaller than 0.03, there is a need
to correct the value of the PMT pressure because of a lack of
curvature on the PMT curve compared to the curvature on the
footing load settlement curve.
Sand
B
Q
e
LENGTH = L
β
D
Pressuremeter
Test
Pressuremeter
Test
RELATIVE
INCREASE IN
CAVITY RADIUS
PRESSURE
on WALL
?
Foundation
Behavior
LOAD
SETTLEMENT
δ
d
Foundation
Figure 16. Transformation of the pressuremeter curve into the
footing load settlement curve
a. Γ FUNCTION: ALL DATA
b. Γ FUNCTION: DESIGN RECOMMENDATIONS
Figure 17. The
Γ
function for the load settlement curve method
(Briaud 2013)
