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CPT 1 2 3
1
2
3
DNV
CPT
qc
Robertson(2012) Kexian Li(2015)
Iwasaki(1982) ArcGIS
The Application of the Seabed Cone Penetration Test for Geologic
Hazard Assessment of Offshore Wind Farm
H.-T.Tsai L.-K. Chien C.-Y. Fang
ABSTRACT
There is great windpower potential on the western offshore of Taiwan. But Taiwan is suffered
from earthquakes and typhoons frequently, and the planned area of the wind farm is covered by
soft seabed. Various marine geological hazards bring a lot of risks and uncertainties to the plan and
design of wind turbine foundations, cables and construction. Taking DNV standards of marine
operations and cases of marine geological hazards as reference, this study considered soft soil and
soil liquefaction into marine geological hazards analysis. This study analyzed the potential of two
kind geological hazards, as soft soil and soil liquefaction, with recent seabed CPT data. Soft soil
was distinguished with qc value at each depth, and summed up the length of soft soil to be graded,
the result was compared with the former research which was analyzed with SPT data
simultaneously. Soil liquefaction analyzed with assessment methods by Robertson (2012) and
Kexian Li(2015) which calculated the cyclic resistance under the cyclic loading of earthquake and
typhoon-induced wave. The above-mentioned analysis results were demonstrated the results of
hazard potential with ArcGIS. Based on the concept of risk assessment, this study defined hazard
factor as the potential of soft soil and soil liquefaction, and vulnerability factor as the construction
cost of wind turbine foundations and cables in the whole offshore wind farm developments, then
combined both factors into risk matrix for the assessment, it indicated the expected influence level
of geologic hazards which affected the cost of offshore wind farm development. This study could
provide the recommended procedure of risk assessment of wind turbine foundations and cables
under geologic hazards during planning of offshore wind farm.
639
39 2017 11 Proceedings of the 39th Ocean Engineering Conference in Taiwan Hungkuang University, November 2017
Keywords: offshore wind farm, marine geological hazards, wind turbine foundations, submarine
cables, seabed CPT, disaster risk assessment
1.
2.
2.1
1
8-15 40
24 CPT
2.2
CPT
qc fs
Ic 2.6
Mayerhof(1956)
(1994)
3
qc
2 CPT
3
2.3
1
g
50
30 0.067g 80%
I 50 0.086g 63%
II 475 0.28g 10%
921 M=7.3 PGA I II (Peak Ground Acceleration, PGA)
1
640
CPT-qc
N
Robertson(1985-2012)
2 (2009)
50
NNW 7.55 12.40
2
Robertson
-CPT CRR
Kexian Li 2013
Robertson-CPT
CRRW
= 1.1 CRRe (1)
Ishihara & Yamazaki 1984
CSRW
3.3.2
FS CRRw CSRW
FS=CRRW / CSRW (2)
Iwasaki1982
PL
PL= F (z)W (z) dz20
0(3)
2.4
3
1 2 3 4 5
(m)
8
%
40
(PL)
0 0-5 5-10 10-15 >15
0 0-5 5-10 10-15 >15
ISDR(2002)
:=
ISO31000 =
GDG(2012)
3
4
51% 1 5
27% 2 4
13% 3 3
7% 4 2
2% 5 1
5
(Hazard)
(Vu
lnerab
ility)
1 2 3 4 5
2 4 6 8 10
3 6 9 12 15
4 8 12 16 20
5 10 15 20 25
4
()
641
3.1
CPT
qc 0.35MPa
5m
2m RA03 RA06RB11
qc
qc
3.2
ArcGIS 50 A PL 8.0-10.3 B PL 15.9-19.3
BH01()BH02(
)BH03()
CPT
CPT
FS PL 50 PL 50
4
6 50
7 50
642
PL
NNW 50 7.55m
12.40
A
B PL 3.38-3.93
PL 3.93-4.86
CPT
ArcGIS
ArcToolBox Geostatistical Analyst
6 8
6
4
2
ArcGIS ArcToolBox Times
8
643
50
AB
50 CPT
ArcGIS
9 50
10 50
9 50
10 50
644
CPT
CPT
GIS
1. (2009)
2. (2011)
3. (2013)
- 35
4. (2013)
5. (2015)
6. (2015)
7. P.K. Robertson and K.L. Cabal(2015), Guide
To Cone Penetration Testing 6th Edition,
pp.25-33, 96-120.
645
646