This document summarizes a study analyzing pile driving data from offshore platforms in Southeast Asia. The study collected data from over 30 platforms across 4 countries and 6 fields. Several common methods for predicting soil resistance during driving (SRD) were evaluated by comparing predictions to back-analyzed driving records. The Alm & Hamre (2001) method, originally developed for North Sea conditions, provided the best match overall. A significant setup effect was observed, with SRD increasing 10-200% within 24-48 hours. The API RP2A 2000 Commentary method was recommended as a conservative upper bound for SRD prediction.

1. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
Synthesis of pile driving data in South East Asia
Emilio Nicolini & Iman Haghighi (speaker)
Cathie Associates, France
Jean Louis Colliat-Dangus
Total, France

2. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
• Scope of the work
• Driven Piles Database
• Soil Conditions
• Soil Resistance to Driving (SRD)
– Common prediction methods
– Back analysis of driving records /
signal matching analysis
• Set-up effect
• Conclusions
Outline of the presentation
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Penetration[m]
SRD [MN]

3. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
• MAIN:
– bound the expected SRD of piles in the area, by zone
– select the best suited SRD calculation method, among the common practice ones
• OPERATIVE:
– collect and organize the wide database of driven piles installation
– select the best quality and complete records
– define the methods to be considered for the SRD calculation, among the common
practice;
– compare the back-analysed SRDs with the calculated ones
– select the best suited SRD calculation method
Scope of the work

4. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
34 Offshore Platforms, 4 Countries, 6 Fields: since 1997
Driven Piles Database (1/2)
COUNTRY
Field
Yadana
8 platforms
Bongkot
12 platforms
Maharaja Lela
2 platforms
Sisi & Nubi
3 platforms
South Mahakam
3 platforms
Peciko
6 platforms

5. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
Instrumented open ended steel foundation jacket piles
Driven Piles Database (2/2)
• Selection criteria:
– Pile geometry:
1.07m < Outer Diameter < 2.44m
45m < Vertical Penetration < 150m
– Completeness of data:
• Geotechnical site investigation,
• Pile Driving Monitoring data.
• Wall thickness generally 38 to 51mm
• More than half of cases a driving shoe of
0.5” extra thickness and 1.5m to 2m long
• Soil Plug depth (in % of pile penetration):
– measured for 18 platforms
– maximum heave of 8% (plug depth higher
than seabed level for 2 platforms)
– maximum settlement of 17%
– 7% in average : mostly coring behaviour.

6. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
Design soil profile was used to calculate the SRD
Soil Conditions
• Bongkot, Thailand:
– 88% cohesive soil; OC clays down to 30m
and NC clays deeper down, medium
dense to dense sand or silty sand.
• Yadana, Myanmar:
– 50 to 70% granular: generally deeper than
20m. Slightly OC clays down to 20m, NC
clays deeper than 40m.
• South Mahakam, Indonesia:
– Nearly entirely cohesive: OC to 20m, NC
at greater depths.
• Peciko, Indonesia:
– 60~90% cohesive NC clays, loose to
medium dense sand layers with fairly large
thicknesses (up to 30m) found between 30m
and 120m depth.
• Sisi & Nubi, Indonesia:
– 80% cohesive, firm to very stiff OC clays
down to 30m, loose sandy layers near
seabed.
• Maharaja Lela, Brunei
– Cohesive OC clays to 15m and NC clays
deeper down. Granular layers at seabed
from 10m to 15m and from 40m to 60m.

7. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
• Methods based on the soil profile and geotechnical parameters:
– Stevens et al. (1982)
– Puech et al. (1990)
– Colliat et al. (1993).
• Methods based on the direct use of CPT results:
– Alm and Hamre (2001); (CPT profiles were available for 20 jackets).
• Methods based on assuming a fixed percentage of the ultimate pile capacity:
– Fugro Singapore method, derived from the API RP 2A 2000 method 2
– PT Fugro Indonesia, derived from the API RP 2A 2000 main text method
– Nippon Steel Construction (NSC), derived from the API RP 2A 2000 main text method
– Cathie Associates Custom method, derived from the Kolk and van der Velde (1996) method for
clayey soils.
SRD Prediction methods commonly used in the area

8. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
• Global method relates recorded blowcount, pile system
(hammer cushion and pile) and the soil behaviour
• Unidimensional wave equation analysis
• Dynamic soil parameters:
– Unique set of dynamic soil parameters for all platforms
• Shaft and toe quake = 2.5mm
• Toe damping = 0.5 s/m and shaft damping = 0.2 s/m, close to Roussel
(1979) recommendations, adopted to develop most of SRD prediction
methods.
Back analysis of driving records

9. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
• 265 Comparisons
(prediction vs back analysis)
• Mostly coring behaviour during
driving
even if several prediction methods
correspond better to back analysed
results considering coring conditions
• Friction degradation observed:
nearly constant blowcount with depth
Evaluation of the SRD prediction method
• None of the methods captured all
the back analysis results
• Alm & Hamre (2001): the overall
trend is generally appropriately
predicted:
– although originally developed for
North Sea soil conditions, promising
results in South East Asia
– in some cases, under-predicting the
SRD at shallow depths.

10. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
Well predicted SRD: 14 cases
(6 cases very well predicted)
Evaluation of Alm & Hamre (2001) method
General trend correctly
predicted: 10 cases
3 Cases with substantial
difference
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Penetration[m]
SRD [MN]
Best Estimate [MN]
Upper Bound [MN]
Back Analysed SRD Pile A2
Back Analysed SRD Pile B1
e.g.EM,SouthMahakamIndonesia
e.g.WP13Bongkot,Thailand
e.g.SWP-G,Peciko,Indonesia
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Penetration[m]
SRD [MN]
Best Estimate [MN]
Unplugged - Upper Bound [MN]
Back Analysed SRD Pile A2
Back Analysed SRD Pile B1
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Penetration[m]
SRD [MN]
Best Estimate [MN]
Unplugged - Upper Bound [MN]
Back Analysed SRD Pile A1

11. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
Set-up factor calculated for all driving interruptions > 45 minutes, based on
back-analysis of restrikes
Set-up factor
Field, Country Min Ave Max
Bongkot, Thailand 1.1 2.0 2.8
Yadana, Myanmar 1.1 1.7 2.5
Sisi & Nubi, Indonesia 1.4 1.5 1.8
Peciko, Indonesia 1.5 2.2 3.0
South Mahakam, Indonesia 1.7 2.0 2.3
24 hours
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0.5
1.0
1.5
2.0
2.5
3.0
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Set-upfactor[-]
Set-up time [hours]
From SRD (Indonesia Sisi & Nubi)
From SRD (Indonesia Peciko)
From SRD (Indonesia South Mahakam)
From Signal Matching

12. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan
• Mostly coring behaviour, no free-fall reported, no clear influence of hammer
type (steam vs hydraulic).
• Alm & Hamre (2001) method provided the best match with the back analysed
SRD in most of cases; improvements could be made.
• Large scatter of set-up factors but with significant set-up (10 to 200% increase
in 24~48 hr).
• API RP2A 2000 Commentary method corresponds in most cases to the pile
capacity after 24hr and is recommended as an upper bound SRD prediction.
Conclusions

13. 3rd International Symposium on Frontiers in Offshore Geotechnics | OSLO 10-12 June 2015 Brussels Paris Newcastle Hamburg Milan