04 Billington Geohazard 2007 NEW

8/19/2019 04 Billington Geohazard 2007 NEW

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2D MASW SURVEYS TO EVALUATE

SUBSURFACE STIFFNESS

Investigations of the 2004 I-40 Landslide

and Other Projects

Ned Bil lington, L.G., Jeremy Strohmeyer, L.G.,

and Alex Rutledge, E.I.T., G.I.T.

Schnabel Engineering11-A Oak Branch Drive, Greensboro, NC 27407


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Schnabel Engineering

OutlineWhat is MASW?

Quick Primer on Surface Waves Raleigh wave motion, Dispersion, SASW

MASW Methodology

Data Acquisition and Processing

2D MASW Applications

Sinkhole Investigations

Abandoned Mine Survey

I-40 Landslide Investigation

Big Slow Movef Study


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What is MASW?

Multi-channel Analysis of Surface Waves

The generation, recording, and analysis of

seismic surface waves (Raleigh waves) todetermine subsurface shear wave velocities.

Shear wave velocity is a direct indication of the

stiffness of subsurface materials.


4/36Schnabel Engineering

What is it good for?1D Shear wave velocity profiles

Site-specific seismic analyses IBC Site Class designation

2D Shear wave velocity cross-sections

Investigating Karst and Sinkhole Features

Mapping Abandoned Mines

Determining Depth to Rock and Rock Quality

Mapping Weak Soil Zones

Locating Fracture Zones

More!



Seismic Waves



Surface Wave Velocity

and Dispersion Lower frequency components of the surface wave have

longer wavelengths and travel deeper in the subsurface,

producing “dispersion” or variation of velocity withfrequency.

V2>V1

V1

f1 f2 f3

V2>V1

V1

f1 f2 f3

V2>V1

V1

f1 f2 f3

V2>V1

V1

f1 f2 f3

A B

Frequency

P h a s e

V e l o c i t y

f1f2

f3

Frequency

P h a s e

V e l o c i t y

f1f2

f3

Frequency

P h a s e

V e l o c i t y

f1f2

f3

Frequency

P h a s e

V e l o c i t y

f1f2

f3



Surface Wave VelocityThe surface wave velocity ranges from 87% to

96% of the shear wave velocity.

Variation is dependent on Poisson’s Ratio.

By determining the surface wave velocit ies, and

by estimating Poisson’s ratio, we can calculatethe shear wave velocity.

ss R V KV V ⎟

⎠ ⎞⎜

⎝ ⎛

++==

ν

ν

1

12.187.0Relationship betweenS & Rayleigh Wave

Velocities



MASW Data Aquisition

Weight drop energy sources: sledgehammer, AWD,

etc.

Engineering seismograph and geophone array

Energy source and array moved along ground

surface to collect additional data

. . .

Seismic Energy Source

Vertical Geophone Array

Surface Wave

Engineering Seismograph

Body Waves



MASW Data Analysis

Recognize surface wave energy

Convert data to frequency domain

Plot surface wave velocity versus frequency

Select representative dispersion curve

Dispersion Curve

Signal-to-Noise Ratio



MASW Inversion Modeling An earth model of shear wave velocity with depth

is generated to match the observed data.

Final Velocity Model

Model Dispersion Curve (solid) vs

Observed Dispersion Curve(dotted)



1D and 2D Models


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2D MASW Applications


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Washington, DCStream Tunnel Sinkhole Survey

South Dr

Line 1

L

i n e

3

Independence Ave

Line 2

Low velocity anomaly

over old tunnel

Low velocity anomalies bymanhole and new tunnel

Low velocity anomaly

over old tunnel

Low velocity anomalies bymanhole and new tunnel


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Chisholm, MN Abandoned Iron Mine Survey

Line A – Deep (48-channel data)

120 140 160 180 200 220 240 260 280 300 320 340

Horizontal Distance (feet)

1400

1420

1440

1460

1480

1500

1520

1540

1560

1400

1420

1440

1460

1480

1500

1520

1540

1560

A p p r o

x i m a t e E l e v a t i o n ( f e e t )

Approx. Nor theastBoring B1

MINE DUMP MATERIAL

GLACIAL TILL

Collapsed Glacial Till?

MINE WORKINGS

BEDROCK

200

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L i n e

A

L i n e

B

L i n

e C

L i n e

A

L i n e

B

L i n

e C

M o d e l e d S h e a r W a v e V e l o c i t y ( f t / s )


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Chisholm, MN

Drilling Results, B-1

Caved mine workings 21 feet thick

Timbers and partially f illed voids

http://images.google.com/imgres?imgurl=http://media.worldgolf.com/wg_blog_media/sweet-spots/DetroitTigersLogo.jpg&imgrefurl=http://www.worldgolf.com/blogs/brandon.tucker/2006/10/12/detroit_is_america_s_best_sports_town_th&h=704&w=480&sz=122&hl=en&start=9&tbnid=RjbuPJck0xvvNM:&tbnh=140&tbnw=95&prev=/images%3Fq%3Ddetroit%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN


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Detroit, MI

Combined Sewer Pipe Sinkhole Study

http://images.google.com/imgres?imgurl=http://media.worldgolf.com/wg_blog_media/sweet-spots/DetroitTigersLogo.jpg&imgrefurl=http://www.worldgolf.com/blogs/brandon.tucker/2006/10/12/detroit_is_america_s_best_sports_town_th&h=704&w=480&sz=122&hl=en&start=9&tbnid=RjbuPJck0xvvNM:&tbnh=140&tbnw=95&prev=/images%3Fq%3Ddetroit%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DNhttp://images.google.com/imgres?imgurl=http://media.worldgolf.com/wg_blog_media/sweet-spots/DetroitTigersLogo.jpg&imgrefurl=http://www.worldgolf.com/blogs/brandon.tucker/2006/10/12/detroit_is_america_s_best_sports_town_th&h=704&w=480&sz=122&hl=en&start=9&tbnid=RjbuPJck0xvvNM:&tbnh=140&tbnw=95&prev=/images%3Fq%3Ddetroit%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN


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Detroit, MI

2D MASW Results (3.3 miles)

http://images.google.com/imgres?imgurl=http://media.worldgolf.com/wg_blog_media/sweet-spots/DetroitTigersLogo.jpg&imgrefurl=http://www.worldgolf.com/blogs/brandon.tucker/2006/10/12/detroit_is_america_s_best_sports_town_th&h=704&w=480&sz=122&hl=en&start=9&tbnid=RjbuPJck0xvvNM:&tbnh=140&tbnw=95&prev=/images%3Fq%3Ddetroit%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DNhttp://images.google.com/imgres?imgurl=http://media.worldgolf.com/wg_blog_media/sweet-spots/DetroitTigersLogo.jpg&imgrefurl=http://www.worldgolf.com/blogs/brandon.tucker/2006/10/12/detroit_is_america_s_best_sports_town_th&h=704&w=480&sz=122&hl=en&start=9&tbnid=RjbuPJck0xvvNM:&tbnh=140&tbnw=95&prev=/images%3Fq%3Ddetroit%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN


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Detroit, MI

Combined Sewer Pipe Sinkhole Study

Example 2D MASW Results

http://images.google.com/imgres?imgurl=http://media.worldgolf.com/wg_blog_media/sweet-spots/DetroitTigersLogo.jpg&imgrefurl=http://www.worldgolf.com/blogs/brandon.tucker/2006/10/12/detroit_is_america_s_best_sports_town_th&h=704&w=480&sz=122&hl=en&start=9&tbnid=RjbuPJck0xvvNM:&tbnh=140&tbnw=95&prev=/images%3Fq%3Ddetroit%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN


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2D MASW to Assist in I-40

Landslide InvestigationSeptember 18, 2004 - Floodwaters from Hurricane

Ivan cause erosion and landslide of I-40embankment near Tennessee border


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Aerial Photographs

4/1992

9/2004

Main SlideSmaller Slide


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MASW Survey - Main Slide

MASW Survey in left-hand lane, eastbound

lanes from Sta 1450 to 2225


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MASW Data Acquisition

24-channel land streamer, 4.5 Hz phones

5-foot geophone spacing, 10-foot source spacing

AWD energy source, 30-foot source offset


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Main Slide - comparison with

boring and tieback data

1450 1500 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000 2050 2100 2150 2200

DOT Stationing (feet)

-80

-60

-40

-20

0

A p p r o x i m a t e D e p t h ( f e e t )

-80

-60

-40

-20

0

FB-10FB-20 FB-7 FB-6 FB-5 FB-4 FB-3

Note: Borings FB-4, FB-5, FB-6, and FB-10 are online. The other borings shown are offset to the south of the line about 18 to 39 feet.

APPROX. EAST

Low velocity anomaly maybe caused by fracture zoneor deeper weathering

Boring with top of boulders (yellow) and top of rock (red)

Approximate top of rock based on borings andshear wave velocities

FB-10

EXPLANATION

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

3 0 0 0

3 5 0 0

4 0 0 0

4 5 0 0

5 0 0 0

Modeled Shear Wave Velocity (feet/second)


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MASW Survey

Smaller Slide

Tunnel


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MASW Results

Smaller Slide

LINE 2LINE 2

H t C i BSM


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Hunters Crossing BSM

2D MASW and Seismic Refraction

Seismic Survey Line


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Section D-D’


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Data Acquistion

2D V M d l (MASW)


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B-1

Adjacent Scarp

Cracks in Asphalt

Act ive Scarp

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2D Vs Model (MASW)


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B-1

Adjacent Scarp

Cracks in Asphalt

Act ive Scarp

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2D Vs Model (MASW)


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2D Vp Model (Refraction)

-340 -330 -320 -310 -300 -290 -280 -270 -260 -250 -240 -230 -220 -210 -200 -190 -180 -170 -160 -150 -140 -130 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

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Vs and Vp Models

B-1

Adjacent Scarp

Cracks in Asphalt

Act ive Scarp

-340 -330 -320 -310 -300 -290 -280 -270 -260 -250 -240 -230 -220 -210 -200 -190 -180 -170 -160 -150 -140 -130 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0

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Closing RemarksMASW is well suited to highway

investigationsCan be collected next to traffic

Acquisition relatively quick on pavement

Not affected by buried, overhead utilities

Provides a physical property useful for design

(shear wave velocity – stiffness)


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Thank you !Thank you !


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Example Soil Boring


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Roadway Embankment Fill:

Silty Sand

Roadway Embankment Fill:

Gravel, Cobbles, and

Boulders

Crystalline Rock:

Quarzite and Meta

Graywacke

Example Soil Boring

04 Billington Geohazard 2007 NEW

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