06_kottke-reference-rock-nga_east.pdf

8/18/2019 06_Kottke-Reference-Rock-NGA_East.pdf

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NGA East Geotechnical Working Group

Youssef M. A. Hashash, Albert R. Kottke, Kenneth W. Campbell,Byungmin Kim, Cheryl Moss, Sissy Nikolaou, Ellen M. Rathje, Walter J.

Silva, and Jonathan P. Stewart

Presented byAlbert R. Kottke, Ph.D. Bechtel Corp

Tuesday August 20th, 2013

Session: Earthquake Loads - Seismic Hazard Assessment II

8/20/2013 NGA-East GWG: Reference Rock 1

Reference Rock SiteCondition for Central and

Eastern North America

Outline

! Reference rock site condition! Definition! Importance for seismic hazard

! Existing recommendation! Reference velocity

! Defining reference velocity! Evaluation of collected data! Recommendation

! Reference local attenuation!

Published models! Recommendation

! Conclusions



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!

Reference Rock Site Condition

! Defined by:! Shear-wave velocity (V s)

!

Compression-wave velocity (V p)

!

Local attenuation (! 0,ref )

! Unit weight

! Appropriate for the Central andEastern North America (stable

continental)


Importance of Reference Condition

•

Present in allvelocity profilesin the region

• Interfacebetween regionaland site-specificmodels

• The reference

condition foramplificationmodels


RegionalCharacteristics

Site SpecificModels

ReferenceCondition


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Existing V s,ref Recommendation

•

EPRI (1993) study is thebasis of current values• V s,ref of 2.83 km/sec

(9,200 ft/sec)

• Based on 16 crustalstructure regions

• V s values computed fromV p inversions and anassumed Poisson’s ratio of0.25


! Published GMPEs use 2.00 to 2.88 km/sec

! Based on simulations

! V s,ref values based on top of assumed crustal profile

4 6 8 10VP (km/s)

2 3 4 5VS (km/s)

60

50

40

30

20

10

0

D e p t h ( k m )

Existing ! 0,ref Recommendation

! EPRI (1993) reported a median ! 0,ref of 0.006 sec and initially proposed a" ln of 0.40.

! EPRI (1993) and Toro et al . (1997)used equally weighted values0.0003, 0.006, and 0.012 sec



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Collection of Velocity Data

! V s and V p measurements thatpenetrate hard-rock were collected

! Journal publications and technicalreports

! Nuclear power plant applications

! Located 283 profiles in study region

!

68 V s,ref values at 27 different locations

!

60 V p,ref

values at 22 different locations


Locations of Collected Data



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Example Velocity Profile


Definition of Reference Velocity

! Based on characteristics of collectedvelocity profiles

! Typical profiles transition from soil toweathered rock to intact rock

! Established a criteria based on:

1. Velocity

2.

Measurement penetration

3. Velocity gradient

4. Geologic age



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-

Reference V s Measurements


2000

2200

2400

2600

2800

3000

3200

3400

3600

3800

S - W a v e V e l o c i t y ,

V s ( m / s )

B e l l B e n d N P P - 8

B e l l e f o n t e N P P - 8

B r o n

s o n - A v a l o n - 1

C a l l a w a y N P P - 2

C

a l v e r t C l i f f s - 3

C h a l k R i v e r ,

O n t a r i o - 1

C

l i n t o n N P P - 1

C o m a n c h e P e a k N P P - 1

F e r m i N P P - 2

G r a n d R e m o u s , O n t a r i o - 1

H a r t f o r d - 1

H a y e s - 1

M o n t i c e l l o R e s e r v o i r - 3

N i n

e M i l e N P P - 1

N o r t h

A n n a N P P - 2

O t t a

w a ,

O n t a r i o - 1

P S E G N P P - 1

R i v e r B e n d N P P - 1

S h e a r o n

H a r r i s N P P - 1

T u r k e y P o i n t N P P - 1

T y n e s i d e , O n t a r i o - 1

V . C . S u m m e r N P P - 8

V o g t l e N P P - 3

W a t e r b u r y - 1

W e s l e y v

i l l e ,

O n t a r i o - 1

W i l l i a m s b u r g ,

O n t a r i o - 1

W i l l i a m S t a t e s L e e I I I N P P - 1 2

Reference V p Measurements


3000

3500

4000

4500

5000

5500

6000

6500

7000

P - W a v e V e l o c i t y , V p ( m / s )

B e l l B e n d N P P - 8

B e l l e f o

n t e N P P - 8

C a l l a w a y N P P - 2

C a l v

e r t C l i f f s - 3

C l i n

t o n N P P - 1

C o m a n c h e P

e a k N P P - 1

D a n i e l s e t a l , U P H 3 - 1

F e

r m i N P P - 3

H a y e s - 1

L u e t g e r t e t a l (

9 4 ) , S P 1 - 1


9 4 ) , S P 2 - 1


9 4 ) , S P 3 - 1


9 4 ) , S P 4 - 1


9 4 ) , S P 5 - 1

M o n t i c e l l o R

e s e r v o i r - 3

N i n e M

i l e N P P - 1

N o r t h A n n a N P P - 2

P S

E G N P P - 2

R i v e r B

e n d N P P - 1

S h e a r o n H a

r r i s N P P - 1

V . C . S u m m e r N P P - 8

W i l l i a m S t a t e s L e e I I I N P P - 9


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Trend with Depth

! Comparedselected referencevelocities withdepth

! Potential to selecthigher velocities atgreater depth(bias)

! Part of the QAprocess

! No trend observed


Within-Profile V s,ref Distribution


Comparing assumed normal and log-normal distributionsindicated that velocities tended to be normally distributed

-4 -3 -2 -1 0 1 2 3 4

Theoretical Quantiles

-2000

-1000

0

1000

2000

O r d e r e d V

s , r e f -

( V s , r e f ) p r ( m / s )

Theoretical

(b)

R2 = 0.95

-2000 -1000 0 1000 2000

V s,ref - ( V s,ref ) pr (m/s)

0

0.02

0.04

0.06

0.08

0.1

P r o b a b i l i t y

(a)

- 0.6 - 0.4 - 0.2 0 0 .2 0.4 0.6

ln[ /(V s,ref ) pr V s,ref ]

0

0.02

0.04

0.06

0.08

0.1


(a)

-4 -3 -2 -1 0 1 2 3 4


-0.6

-0.4

-0.2

0

0.2

0.4

0.6

O

r d e r e d l n [

/ ( V s , r e f ) p r

V s , r e f

]

(b)

R2 = 0.96


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Characterizing the Uncertainty


The observed trend in the standard deviation with mean profile velocityis removed by characterizing the uncertainty using the coefficient ofvariation (standard deviation / mean)

2000 3000 4000 5000 6000 7000

Mean Profile Velocity (m/s)

0

200

400

600

800

P r o f i l e S t a n d a r d D e v i a t i o n ( m / s )

S-Wave P-Wave

2000 3000 4000 5000 6000 7000

Mean Profile Velocity (m/s)

0

0.04

0.08

0.12

0.16

0.2

P r o f i l e C o e f f i c i e n t o f V a r i a t i o n

Within-Region V s,ref Distribution


Theoretical

2000 2400 2800 3200 3600V s,ref (m/s)

0

0.05

0.1

0.15

0.2

0.25


(a)

-2 -1 0 1 2


2000

2400

2800

3200

3600

O r d e r e d

V s , r e f

( m / s )

(b)

R2 = 0.98

Distribution of mean values from each location indicate a slightlyskewed distribution that can be approximated by a normal distribution.


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Poisson’s Ratio


B e l l

B e n d N P P

B e l l e f o n t e N P P

C a l l a w a y N P P

C a

l v e r t C l i f f s

C l i n t o n N P P

C o m a n c h e

P e a k N P P

F e r m i N P P

H a y e s

M o n t i c e l l o

R e s e r v o i r

N i n e

M i l e N P P

N o r t h

A n n a N P P

P S E G N P P

R i v e r

B e n d N P P

S h e a r o n H a r r i s N P P

T u r k e y

P o i n t N P P

V . C . S u

m m e r N P P

W i l l i a m S t a t e s L

e e I I I N P P

0.24

0.26

0.28

0.3

0.32

0.34

P o i s s s o n ' s R a t i o

Calculated

Assumed

Mean value of 0.28

Weathered Zone

!

Collectedinformation onthe weatheredrock

! Clearlyobserved atfour locations

! Identified:

• Thickness• Velocity range


100

80

60

40

20

0

D e p t h ( m )

1000

1500

2000

2500

3000

3500

4000

S - W a v e V e l o c i t y ( m / s )

Bell Bend NPPBellefonte NPP

NorthAnna NPP

Williams StatesLee III NPP

(a) (b)


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Weathered Zone Properties


1 10 100Weathered Zone Thickness (m)

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2

S - W a v e V e l o c i t y R a t i o

Bell Bend NPP

Bellefonte NPP

North Anna NPP

Williams States LEE III NPP

Mean thickness = 15 mMean Vs ratio = 1.53

Velocity Gradient

!

Defined byincrease invelocity withdepth

! Mean gradient:

! Reference rock2 per sec

! Weathered rock165 per sec


0 200 400 600Velocity Gradient [(m/s)/m]

0

1

2

3

4(b) Weathered rock

µ = 165 (1/s)

-100 0 100 200 300 400Velocity Gradient [(m/s)/m]

0

10

20

30

40

C o u n t

(a) Reference rock

µ = 2 (1/s)

0 100 200 300 400 500 600 700Velocity Gradient Difference [(m/s)/m]

0

1

2

3

4

5

C

o u n t


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Range of V s,ref

! Collected data indicate V s,ref variesbetween locations

! Two potential methods define therange:! Statistics:

! 95% confidence interval: 2.12 to 3.78 km/sec

! Influence of V s,ref range on the ground motion?

! Amplification! Specify range using 5% difference in

amplification

! Amplification estimated by !#$ ! "#$ #

! 2.7 to 3.3 km/sec


Recommended Reference Velocity

!"#$ '()$" *)+,"

! "#$%& "1) 234'56 !1. 7 "1" 234'56

! (#$%& ,1, 234'56 ,1) 7 -1* 234'56



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Reference Local Attenuation (! 0,ref )

! 896:; :9=?:@:35(5@ ) *#$%& 6A:@:6(5@BC5' AB&A7D@5E%5=6F :9=

! G5H=5I D@93 AB&A7D@5E%5=6F6A:@:6(5@B'>6' 9D@569@I5I &@9%=I39>9='

! J=(5@?@5(5I :' I:3?B=&I%5 (9 =5:@7'B(5 5K56('L:IIB>9=:; (9 MN


$O5@ $=I5@'9= :=I P9%&A L*0/+N

! Existing studies used:

! Use recorded CENA ground motions

Sources Considered


Anderson (91) Edwards (12)

Atkinson (84) Hough et al. (88)

Atkinson (96) Silva and Darragh (95)

Atkinson and Boore (06) Silva et al. (88)

Campbell (09) Silva et al. (99)

Chandler et al. (06) Toro and McGuire (87)

Chapman et al. (03) Van Houtte et al. (11)


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Local Attenuation Models


Recommended local attenuation


Distribution Parameter Value

Type of Distribution Lognormal

Median, 0, ref ! (sec) 0.006

Aleatory Standard Deviation,0,ln ref !

" (sec) 0.43

Epistemic Standard Deviation,0,ln ref !

# (sec)

Excluding source, path, and site uncertainty

Including source, path, and site uncertainty

0.12

0.20

Total Standard Deviation,0, 0, 0,

2 2

ln ln lnref ref ref ! ! ! $ " # = +


Including source, path, and site uncertainty0.45

0.47

Coefficient of Variation ( )2COV exp( ) 1$ = % Aleatory variability

Epistemic uncertaintyExcluding source, path, and site uncertainty


0.45

0.47

0.50

95th

Confidence Interval; 2$ ± Range (sec)



0.0024 – 0.0148

0.0023 – 0.0154


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Conclusions

! Reference rock velocity! V s,ref = 3,000 m/s (2,700 -3,300 m/s) ! V p,ref = 5,500 m/s (5,000 -6,100 m/s)

!

Local attenuation

! ! 0,ref = 0.006 sec

! Log-normal distribution

! Log standard deviation = 0.43

!

Recorded motions will be incorporated oncethey become available


Acknowledgments!

Funding! U.S. Nuclear Regulatory Commission!

U.S. Department of Energy!

Electric Power Research Institute!

U.S. Geological Survey

! Support from:!

Bechtel! Farhang Ostadan! Tarek Elkhoraibi

! Fugro! Jeff Bachuber! Michael Gray

! US NRC! Richard Rivera-Lugo

!

Undergraduate and graduate students:!

Michael Musgrove!

Khatereh Khodaverdi!

Ataya Eltibi!

Paul Khauli


06_kottke-reference-rock-nga_east.pdf

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