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37 2015 11 Proceedings of the 37th Ocean Engineering Conference in Taiwan National Chung Hsing University, November 2015

1 2 3 4

1 3

4 5

NORSOK

CPT Ic SPT

A Study of Foundation Design Standard and Localization of Geotechnical Parameters for Offshore

Wind Farm Chia-Ch Lien-Kwei Chen* Shu-Yi Chiu Tsung-Wei Feng

* Professor, Department of Harbor and River Engineering, National Taiwan Ocean University

ABSTRACT

The related offshore wind farm geotechnical design & ground investigation standard around the world were collected and reviewed in this study. The key point of offshore geological risk is discussed. And the Taiwan local offshore wind farm geotechnical design and ground investigation standard can be establish by review the certain offshore standard and make recommendations for domestic offshore wind farm certification requirement. On the other hand, this study according to the suggestion of geotechnical investigation by the Norsok Standard, the required valuable geotechnical parameters need to investigate is suggested. And according to the offshore wind farm geological section profiles, the reference geotechnical parameters are established. Based on the in situ SPT and CPT with the geotechnical parameters were discussed. Meanwhile, the soil classification was performed by use of soil behavior index (Ic) for Cone Penetration Test (CPT). It could be found that there are many thin layer of soft soil existed in each bore hole. On the geotechnical design stage, the geotechnical problem caused by thin layer of soft soil must be concern with cautions.

Keywords: Offshore wind Farm; Foundation Design Standard; Geotechnical Investigation; Localized Geotechnical Parameters; SPT; CPT

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2.1

ABSAPIBSHDNV

GLIECNORSOKEurocode

BSH BSH Standard IEC

ISO 19900

DNV

GL

1

1

2.2

1 DNV-OS-J101

DNV Classification Note 30.4 Foundation

API RP-2A

2.3

DNV(2014)

2

1

API

DNV-OS-J101DNV CN 30.4

DNV-OS-J101

DNV-OS-J101

DNV CN 30.4

API

DNV-OS-J101DNV CN 30.4

EA-Pfaehle

-711-

APIDNV CN

30.4

APIDNV CN

30.4

(t-z)

APIDNV-OS-J101DNV

CN 30.4

(p-y)

APIDNV-OS-J101DNV

CN 30.4

DNV CN 30.4

APIDNVDNV-OS-J101DNV

CN 30.4

API RP-2EQ

DNV-OS-J101DNV CN 30.4GL

DNV CN 30.4

DNV CN 30.4

APIAPI RP-2A DNV CN 30.4DNV Classification Note 30.4 Foundation. GLGL IV Part2

EA PfhleRecommendations on Piling , DGGT 2014

2

CPT

p-y

SPT-N

CPT-qc /

SPT or CPT

3.1 NORSOK Standard G-001 Marine Soil

Investigation(2004)

(1)(2)

(3) (2014)

3

3

(m)

SPT-

N

(kN/m3)

Su (kPa)

(deg)

E (kPa) e

6.5-7(6.84) SM1-10(4)

17.3-19.9(19.0) -- 22-27 9810

0.59~0.89(0.71)

10-11.5(10.5)SP-S

M 5-33(21)

17.7-20.6(19.3) -- 30-35 51503

0.83~0.86(0.64)

7.46-11.9(9.95)CLML

5-11(7)

16.8-21.4(18.7) 12.57* 31 6287

0.56~1.05(0.82)

12.6-18.0

4 (15.58)

CL-ML

7-30(15)

17.8-20.6(19.5) 24.88 31 12441

0.53~1.06(0.7)

13.3-17.7(14.83)ML

SM14-41(21)

16.0-21.6(19.2) -- 30-35 51503

0.43~1.49(1.39)

18.3-25.5(22.3)SMML

16-61(34)

16.-21.9(19.9) -- 35 83385

0.42~1.2(0.63)

3.2

SPT

CPT

3.2.1 SPT-N Su

SPT-N

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(1959)

Terzaghi(1967)(1977)

2

SPT-N

(1959)

SPT-N

0.0157 0.0184Su N (1)

N SPT-N Su (kgf/cm2)

2 SPT-N

3.2.2 SPT-N Dunham(1954)(1959)

BH-1

BH-05,06

3 (SM)

= 0.5829N + 18.801 (deg) (2) R2 = 0.6512

= 21.007*e0.0184N (deg) (3) R2 = 0.6686 SM

Dunham(1954)(1959)

3

3.2.3 CPT Ic CPT

CPT

Robertson (2014)

CPT

CPT SBT

IcIc

SBT 4 2 2 0.5((3.47 log ) (log 1.22) )C t rI Q F (4)

tQ 0 0( ) / 't v vq

rF = 0( / ( )) *100%s t vf q CPT

Ic

4 Ic

Ic 2.6

CPT

2 312m

-713-

4 2

3.2.4 CPT cq 0.510Mpa

5

1 2 cq

1Mpa

(1990) cq

1Mpa

Eurocode(2007) cq

1Mpa

3.3 SPT CPT SPT-N

N60 SPT cq

4

SPT

CPT

N60

SPT-N CPT-qc CPT

5

4 N60

R2

600.233* 1.999cq N 0.615 602.521* ln 0.596cq N 0.543

600.0412.628* Ncq e 0.447 600.348* 1.66cq N 0.563 601.15* ln 0.205cq N 0.777

600.2950.374 * Ncq e 0.625

ABSAPIBSHDNVGL

IECNORSOKEurocode

SPT-N

SPT-N

CPT

1km CPT

-714-

CPT

Ic SPT

1 CPT

1. (1990)

648-660

2. (2009) N

() 654

3. (2012)

4. (2014)

-

5. (2014)

6. American Bureau of Shipping, ABS (2014) ABS

#176 Guide For Building And Classing

Bottom-Founded Offshore Wind Turbine

Installations.

7. American Petroleum Institute, API (2002) API

RP-2A-WSD Recommended Practice 2A-WSD,

Recommended Practice for Planning, Designing

and Constructing Fixed Offshore

PlatformsWorking Stress Design, Twenty-First

Edition, Errata And Supplement 1.

8. British Standard (2009) BS EN 61400-3 Wind

Turbines Part 3: Design Requirements for

Offshore Wind Turbines.

9. Bundesamt fr Seeschifffahrt und Hydrographie,

BSH (2014) Standard Design of Offshore Wind

Turbines.

10. Bundesamt fr Seeschifffahrt und Hydrographie,

BSH (2014) Standard Minimum requirements for

geotechnical surveys and investigations into

offshore wind energy structures, offshore stations

and power cables.

11. Det Norske Veritas, DNV (1992) DNV

Classification Notes 30.4 Foundation.

12. Det Norske Veritas, DNV (2014) DNV-OS-101

Design of Offshore Wind Turbine Structures.

13. European Commission (2004) EN 1997-1

Eurocode 7: Geotechnical design - Part 1:

General rules.

14. European Commission (2007) EN 1997-2

Eurocode 7: Geotechnical design - Part 2: Ground

investigation and testing.

15. Germanischer Lloyd, GL (2012) GL IV Part 2

Guideline for the Certification of Offshore Wind

Turbines.

16. International Electrotechnical Commission, IEC

(2005) IEC 61400-1 International Standard

Wind Turbines Part 1: Design Requirements,

Third edition.

17. International Electrotechnical Commission, IEC

(2009) IEC 61400-3 International Standard

Wind Turbines Part 3: Design Requirements for

Offshore Wind Turbines.

18. P. K. Robertson (2006) Guide to In-Situ Testing,

Gregg Drilling & Testing, Inc.

19. P. K. Robertson, K.L. Cabal (2014) Guide to Cone

Penetration Testing for Geotechnical Engineering,

6th Edition, Gregg Drilling & Testing, Inc.

37.pdf_page_72737.pdf_page_72837.pdf_page_72937.pdf_page_73037.pdf_page_73137.pdf_page_732