UNCERTAINTY AND RELIABILITY - Introduction to Soft Soil Geotechnique: Content, Context and Application - page 112

adopted in the wrong layer. Fortunately, it has little implication on the production
Q , but the influence area

is largely underestimated.

load Q [kN] load Q [kN]

test test

pile settlement [mm] pile settlement [mm]

Figure 8.5a Pile load test ESOPT-II 1989 (Van Weele)

Ratio between predicted and measured displacement at
50% of the ultimate bearing capacity (static loading test)
Expert

Pile 1 Pile 2 Pile 3 Pile 4

1
2
3
4
5
6
7
8
9

-
3.32
-
1.20
2.00
0.60
1.03
1.42
1.21

0.59
0.80
-
1.10
1.06
0.63
0.79
1.46
0.74

1.32
1.53
-
1.29
1.38
1.35
1.26
1.04
1.41

0.70
1.08
1.06
1.25
1.50
1.22
0.80
0.71
1.00

Max/Min
Average

5.53
1.54

2.32
0.90

1.47
1.32

1.78
1.04

Figure 8.5b Pile load test ASWTP-4, 1992

Pile load-settlement behaviour
During the Penetration Testing Symposium ESOPT-II, in 1982, a prefabricated
prestressed concrete pile (15 m, 0.25x0.25 m 2 ) was driven and statically loaded till
failure. Long before, extensive site and lab investigations had been performed.
With the results of these tests, 15 international experts made a prediction, using
their best methods and experience. The predictions together with the real result are
shown in Fig 8.5a. The predicted pile loading at 10 mm settlement varies from 360
to 1110 kN, and predicted failure load ranged from 600 to 1500 kN.