Wolf Creek Dam Foundation Remediation
Presented by Josh Bomar, P.E. Geological Engineer USACE, Nashville District
03 August 2011 Geohazards Conference – Chattanooga, TN
US Army Corps of Engineers
BUILDING STRONG® Project Location
Wolf Creek Dam
US Army Corps of Engineers
BUILDING STRONG® Flood Control $34 million/yr
Hydropower $77 million/yr Lake Cumberland
Recreation 5 million visitors per year $129 million impact on local economy
Water Supply Between 100k and 200k Users
Water Quality Whole Cumberland River System Relies on Wolf Creek for Cool, Oxygenated Water USFWS Trout Hatchery Downstream over $1 million per year US Army Corps of Engineers
BUILDING STRONG® Site Stratigraphy
BUILDING STRONG® Foundation Treatment
SolutionUS Army Corps ofFeatures Engineers Intercepting BUILDING STRONG Cutoff Trench ® BUILDING STRONG® “Overhangs and loose rock will be removed only where they cross the lines of the trench, since the earthfill in the sides of the trench will have the function only of stability and not of an absolutely uniform tight contact with the trench walls.”
Slide 7 BUILDING STRONG® 1960’S Problem Areas
Sinkholes
Muddy Wet Areas Flow Starting in 1967 1964
BUILDING STRONG® 1968 Sinkhole
Sinkhole
Note the body language
BUILDING STRONG® BUILDING STRONG® 10 BUILDING STRONG® 11 1960’s and 70’s Remedial Features Embankment Wall
Switchyard Wall
Earth Emb Grout Lines Switchyard
SwitchyardBUILDINGWall STRONG® Post Construction Distress Indicators
BUILDING STRONG ICOS Diaphragm Walls ® Post Construction Distress Indicators
BUILDING STRONG® Post Construction Distress Indicators
Headwater
D-323A – 586.10
VWP1-1 – 596.8 VWP1-2 – 571.8
D-268A – 568.3
WA-59R – 502.8
VWP1-3 – 551.8 VWP1-4 – 536.6 Tailwater
BUILDING STRONG® Potential Failure Mode & Ongoing Foundation Remediation Piezometer Elev. 773 Elev. 750
Elev. 680
Existing Wall
TOR Elev. 570±
Elev. 495
Elev. 475 Base of New Wall Elev. 425 Bottom of Grout
BUILDING STRONG® Instrumentation – Cone Section
BUILDING STRONG® Instrumentation . 200+ Piezometers . 50 Inclinometers . 11 Extensometers . 101 Surface Monuments . 32 Crack Pins
BUILDING STRONG® Foundation Remediation Contract
. Two Phase Approach ►Phase 1: Grouting ►Phase 2: Barrier Wall Construction
BUILDING STRONG® 19 Foundation Grouting Contract
• Advanced Construction Techniques • Low Bid Contract • 1300 Holes • 900,000 gallons of grout • $70 million • Completed September 2008 Dual Line Grout Curtain
BUILDING STRONG® Overburden Drilling & Casing Installation – Rotosonic Drilling
BUILDING STRONG® Rock Drilling with a Cubex Rig
BUILDING STRONG® Wash Borehole Before Grouting
BUILDING STRONG® Optical Televiewer
BUILDING STRONG® Grout Hole Imagery
BUILDING STRONG® Grout Hole Imagery
Before Washing After Washing
BUILDING STRONG® Grout Cart Injection System Radio Tower
Packer
Grout & Return Hose
BUILDING STRONG® Schematic of Grout Injection System
Flow Meter Pressure Gauge Grout Hose
Grout Plant Ground Surface
Mixer Return Hose Agitator
Pumps Valves regulate Grout Header pressure and flow PVC Standpipe GROUT CART
Top of Rock
NOTE: Water Pressure Testing and Borehole Grouting uses the same equipment Grout Inflatable Packer
BUILDING STRONG® Grouting Results – Trend Plots
BUILDING STRONG® Grouting Results
BUILDING STRONG® Pre-Con Site Characterization . EMBANKMENT ► Mineralogy ► Gradation ► Atterberg Limits ► Hydrometer Analysis . BEDROCK ► Point Load Test ► Unconfined Compression ► Cerchar Abrasiveness Index ► Rock Structure ► Discontinuities ► Bedding Heterogeneity
BUILDING STRONG® 31 Barrier Wall Contract
• Contractor: Treviicos – Soletanche JV • Best Value - Request for Proposals Downstream • 4000-ft Concrete Barrier Wall • Approx. 210,000 cyds of Concrete Grout Line • $340 Million
Upstream Grout Line
Barrier Wall
Alignment BUILDING STRONG® 32 Barrier Wall Construction . Guidewall Construction . Pre-Excavation . Encasement Wall . Pilot / Exploratory Holes . Construction Techniques ►Combination Barrier Wall (CBW) ►Pile Barrier Wall (PBW) ►Slot Pile System (SPS) . Assessing Wall Continuity at Depth ►Instrumented Equipment
BUILDING STRONG® BUILDING STRONG® 34 BUILDING STRONG® Pre-Excavation - Clamshell 9’-2”
4 ft PLAN
PROFILE
~170-ft
BUILDING STRONG® Encasement Wall - Hydromill 9’-2” 5” min overlap
6 ft P S P PLAN
Embankment
P S P
Alluvium
Rock
PROFILE BUILDING STRONG® Encasement Wall Verticality
(2.434, 5.986) (2.151, -1.896) Biaxial Inclinometer +Y
-X +X 4.10˚
-Y
(-2.633, 6.168) (-2.916, -1.714) 0.25% Tolerance Theoretical (Vertical) Section Cut @ 120-ft Actual Deviation (4.085, 3.543) (3.902, -2.803)
3.30˚
(0.066, 3.661) (-0.177, -2.685)
BUILDING STRONG Section Cut @ 166-ft ® Encasement Wall Verticality 1.0 m Sensor: P2 1.0 m
0.96 m 0.87 m 120 FT 0.96 m + 0.87 m = 6.0 ft
Y’ Y Y’ = Upstream Y = Downstream
(+) Y
(-) X’P2 P1 X (+) Sensor Unit 25˚
(-) Y’
BUILDING STRONG® Concrete Placement
BUILDING STRONG® Pilot Hole – Wassara Water Hammer 31”
PLAN
Embankment
Alluvium
Rock
PROFILE BUILDING STRONG® Pilot Hole Verticality . PARATRACK 2 ►Tri-Axial Accelerometers & Magnetometers . Inclinometer ►Inserted Inside Drill Casing
BUILDING STRONG® Pilot Hole Verticality -10 -5 0 5 10 0 Reading (Inches) Polar Plot Upstream (-) / Downstream (+) Paratrack 10 Inclinometer 330˚ 30˚ Tolerance 8 50
6 300˚ 60˚ 4 100 2
0 -10-8-6-4-20246810 150 -2 Deviation (in.) Depth (Ft.)
-4
Upstream (-) / Downstream (+) / Downstream (-) Upstream 120˚ 240˚ -6 200
-8 150˚ 210˚ -10 250 Inclinometer Deviation (in.) Left (-) / Right (+)
Paratrack BUILDING STRONG® Pile Barrier Wall - PBW 31” Min. 2’ Wall Thickness
PPS
Embankment
Alluvium
Rock
BUILDING STRONG® BUILDING STRONG® PBW Verticality Biaxial Inclinometer . Biaxial Inclinometer ►Multiple Shots to Reduce Error . KODEN ►Dimensions of Final Excavation
+Y
-X +X 6.7-in -Y
0.25% Tolerance Theoretical (Vertical) Actual Deviation
BUILDING STRONG® PBW Verticality -10 -5 0 5 10 0 Reading (In.) 10 Wirth Center Left (-) / Right (+) 330˚ Koden 'Center' 30˚ Tolerance 8 50 6 300˚ 60˚ 4 100 2
0 -10-8-6-4-20246810 150 -2 Depth (Ft.) Deviation (in.)
-4
Upstream (-) / Downstream (+) / Downstream (-) Upstream 120˚ 200 240˚ -6
-8 150˚ 210˚ 250 Wirth -10 Deviation (in.) Left (-) / Right (+) Koden 'Center' BUILDING STRONG® Concrete Placement
BUILDING STRONG® 48 Combined Barrier Wall
10’- 6” 2’-7”
Embankment
Alluvium
Rock
BUILDING STRONG® 49 Slot Pile System - SPS 31” Completed Segment
P
Embankment
Alluvium
Rock
BUILDING STRONG® Consistency of Multiple Surveys -10 -5 0 5 10-10 -5 0 5 10 0 0 Reading (Inches) Wirth Center Reading (Inches) Left (-) / Right (+) Upstream (-) / Downstream (+) Paratrack
50 Inclinometer 50 Koden 'Center'
Tolerance
100 100
150 150 Depth (Ft.) Depth (Ft.)
200 200
250 250
BUILDING STRONG® 10
330˚ 30˚ 8
Wirth 6 Koden 'Center' 300˚ 60˚ Inclinometer 4 Paratrack
2
0 -10-8-6-4-20246810
-2 Deviation (in.)
Upstream (-) / Downstream (+) / Downstream (-) Upstream -4
120˚ 240˚ -6
-8 150˚ 210˚ -10 Deviation (in.) Left (-) / Right (+) BUILDING STRONG® Assessing Wall Continuity at Depth
150-FT
WIRTH/Secant Inclinometer Pilot Hole PARATRACK Primary Panel
Pilot Hole Inclinometer 0.25 % Tolerance / Theoretical Secondary Panel
BUILDING STRONG® Assessing Wall Continuity at Depth
250-FT
270-FT
WIRTH/Secant Inclinometer Pilot Hole PARATRACK
Pilot Hole Inclinometer 0.25 % Tolerance / Theoretical BUILDING STRONG® QUESTIONS
BUILDING STRONG®