OrganizationDateSeattle City CouncilDec. 15, 2014

Surface, Building and Benchmark Settlement Since Nov. 24, 2014

0

Settl

emen

t (in

.)

-0.125-0.25

-0.375-0.05

-0.625-0.75

-0.875-1

-1.125-1.25

24 - Nov 29 - Nov 4 - Dec 9 - Dec 14 - Dec

Deep Benchmark 1Occidental Ave S and Railroad Way S

-0.636 -0.672

-0.696 -0.672

-0.636

Survey Accuracy

-0.756

Dec 12

Surface, Building and Benchmark Settlement Since Nov. 24, 2014

0

Settl

emen

t (in

.)

-0.125-0.25

-0.375-0.05

-0.625-0.75

-0.875-1

-1.125-1.25

24 - Nov 29 - Nov 4 - Dec 9 - Dec 14 - Dec

Deep Benchmark 2Second Ave and Marion St

-0.24

-0.288

-0.24

-0.252

-0.24

-0.24

Survey Accuracy

Dec 12

Surface, Building and Benchmark Settlement Since Nov. 24, 2014

0

Settl

emen

t (in

.)

-0.125-0.25

-0.375-0.05

-0.625-0.75

-0.875-1

-1.125-1.25

24 - Nov 29 - Nov 4 - Dec 9 - Dec 14 - Dec

S Jackson St and First Ave S(Survey Control Point - JACK)

-1.164

-1.164-1.176 -1.236 -1.176 -1.152

-1.14

Survey Accuracy

Dec 12

Surface, Building and Benchmark Settlement Since Nov. 24, 2014

0

Settl

emen

t (in

.)

-0.125-0.25

-0.375-0.05

-0.625-0.75

-0.875-1

-1.125-1.25

24 - Nov 29 - Nov 4 - Dec 9 - Dec 14 - Dec

S Main St and First Ave S(Survey Control Point - MAIN)

-1.044

-1.08-1.152 -1.116

-1.152

-1.032

-1.056

Survey Accuracy

Dec 12

§̈¦5

Access Shaft

TunnelAlignment

Alaskan WayViaduct

DBM3

DBM2

DBM1

X34

X32

X52

X51

X50

X49

X47

X07

X06

Fire

King

Jack

Main

MYST

Pike

Event

MTC019

GP-276

GP-232

UnitedGP-319

Spring

Target

SMP 405

SMP 408

Tidal G

COS 5020

Bergman

SMP 409

-0.9

-0.7-0.8

-0.6-0.5

-1.0

-0.4

-0.3

-0.2

-1.1

-1.2

-0.1

-1.3

-1.4

-0.1

-0.9

-0.6

-0.6

-0.2

-1.4

-0.7

-0.5

-0.9

-0.7

-0.8

-0.8

-0.1

-0.7

-0.5

-0.2

-0.4

-0.3

-0.1

µ0 500

Feet

SETTLEMENTInches

!(

Survey Control Point

Near Surface Settlement Point!(

12 DEC 14

-1.47 to -1.4-1.39 to -1.3-1.29 to -1.2-1.19 to -1.1-1.09 to -1-0.99 to -0.9-0.89 to -0.8-0.79 to -0.7-0.69 to -0.6-0.59 to -0.5-0.49 to -0.4-0.39 to -0.3-0.29 to -0.2-0.19 to -0.1-0.09 to 0

Ground Surface Settlement,as of December 12

1. This plot is intended to present information regarding the effect of dewatering of TBM Access Shaft on groundwater levels in the project area.

3. ESUs were estimated by WSDOT based on boring logs, where available, or from comparison of the measurement point depth with the Geotechnical Baseline Report centerline profile.

NOTES:

FIG. 12. Observations are based on data obtained by STP and downloaded from Geoscope on 12-1-2014.

4. Drawdown was calculated by subtracting the initial reading of the measurement point (prior to 9-21-2014) from the average of the readings observed between 11-17-2014 and 12-01-2014.

I I I I I I I I I I I I I I I200+00 202+00 204+00 206+00 208+00 210+00 212+00 214+00 216+00 218+00 220+00 222+00 224+00 226+00 228+00198+00

Outwash Sand

Clay w/ Silt Interbeds

Till

Recent Fill

AccessShaft

Current Groundwater Head(Lower Aquifer)

Preconstruction Groundwater Head(Lower Aquifer)

0

91

19

20

14

15

1284

1050

21

0

14

11 7

7163 102

83

107

104

98

10489

140

89

20

14

20

19

1416

12

11/20

/2014

11/29

/2014

12/5/

2014

12/5/

2014

12/5/

2014

12/6/

2014

12/6/

2014

11/29

/2014

12/5/

2014

12/1/

2014

12/1/

2014

12/1/

2014

12/6/

2014

12/6/

2014

12/1/

2014

11/29

/2014

12/1/

2014

12/1/

2014

12/1/

2014

11/26

/2014

12/5/

2014

12/5/

2014

12/5/

2014

12/5/

2014

12/5/

2014 12/6/

2014

12/6/

2014

S KIN

G ST

S JAC

KSON

ST

S MAI

N ST

S WAS

HING

TON S

T

YESL

ER W

AY

COLU

MBIA

ST

MARI

ON ST

MADI

SON S

T

SPRI

NG ST

SENE

CA ST

-240 -240

-200 -200

-160 -160

-120 -120

-80 -80

-40 -40

0 0

40 40

80 80

AWV Central Waterfront Bored Tunnel TBM Access Shaft

0 200Feet

Feet0 40

Vertical Scale:

Horizontal Scale: ±

Vertical Datum: NAVD 88

DrawdownLevel

(ft)

Original ObservedGroundwater Level

Drawdown ObservedGroundwater Level

0 - 23 - 1011 - 2021 - 3031 - 50Over 50

!(!(!(!(!(!(

YX

NOTE: Vertical Exaggeration = 5X

12 DEC 14 21-1-21400-053

GROUNDWATER DRAWDOWN FROMLOWER AQUIFER DEPRESSURIZATION

Groundwater Drawdown from Lower Aquifer Depressurization

#*

#*

Lower Aquifer(Outwash Sand)

Aquitard(Clay w/ Silt Interbeds)

Unconfined Groudwater LevelScreened Observation Well

In Upper Aquifer

G r o u n d S u r f a c eG r o u n d S u r f a c e

Upper Aquifer(Recent Soil & Fill)

Confined Groundwater Level

Screened Observation WellIn Lower Aquifer

12 DEC 14

Generalized Aquifer Profile with Groundwater Wells

100 lbs.

100 lbs.

Coil SpringCoil Spring

12 DEC 14

Schematic of Pressure changes due to Dewatering

Alaskan Way Viaduct REPLACEMENT

PROGRAM

-2

-1

0

2014 (Dec 7)

Settlement in inches

Alaskan Way Viaduct Survey Results

2014 (Oct. 18)2010

100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117

S King StreetS Main StreetS Washington Street

prepared on Dec. 12, 2014

S Jackson Street