06s-brossi, bassola and bedford muro wolf creek
DESCRIPTION
fundaciones especialesTRANSCRIPT
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US Army Corps of Engineers
BUILDING STRONG®
Wolf Creek Dam Barrier Wall Construction
Mr. Brook Brosi, PG
US Army Corps of Engineers
Mr. Lyndon Bedford & Mr. Pablo Bassola
Treviicos-Soletanche Joint Venture
DFI Slurry Wall Seminar
June 27, 2013
OUTLINE
INTRODUCTION
FOUNDATION PROBLEMS & PHOTOS
1970’s GROUTING & WALL CONSTR.
SETUP FOR BARRIER WALL CONSTR
5-STEP BARRIER WALL CONSTRUCTION
CONCLUSIONS
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INTRODUCTION
Wolf Creek Dam
Largest manmade reservoir east of the Mississippi River. Located in central-southern Kentucky. Produces $77,000,000-per-year in
hydropower for treasury (2006). Designed in the 1930’s, built mostly in
1940’s, Powerhouse completed in 1952.
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Location of Site
Wolf Creek Dam
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Downward Slope of
Cut Off Trench
Cut Off TrenchToe of Compacted Fill
Drainage Blanket
Alluvium and Disposal
Embankment Plan
0 1+00A 2+00A 3+00A 4+00A 5+00A1+00B2+00B3+00B4+00B5+00B
Elev. 773
Cutoff trenchLimestone Bedrock
Dam
Soil Foundation
Pool
Embankment Profile
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Detailed Geology of Site
Source: Kentucky Geological Survey
The Problem with Wolf Creek’s foundation:
KARST
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Foundation Treatment
Cave
Cave
Solution Features
Original Construction
in 1940’s
Original Construction
in 1940’s
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Core TrenchOriginal
Constructionin 1940’s
Approx New WallLocation
Pinnacle
Original Construction
in 1940’s
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Approx New WallAlignment
Original Construction
in 1940’s
Original Construction
in 1940’s
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FOUNDATION PROBLEMSIN 1960’S
Initial Distress Indicators1967 - 1968
SPILLWAY
MUDDY WATERSHOW
POWERHOUSEN
SINKHOLE 3-13-68
SINKHOLE 4-22-68 SINKHOLE8-22-67
SWITCH YARD WET AREAS
Dam Embankment
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Sinkhole
Switchyard
1968 Sinkhole
LATE 1960’S- EARLY1970’SEMERGENCYGROUTING
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1960’s/1970’s Remedial Grouting
Concrete Monoliths
LAKE
RIVERGrout Lines
Solution Features
1960’s and 70’s Remedial Grouting
Concrete Dam
Earth Emb
SwitchyardGrout Lines
Crest Grout Line
Wrap-Around Grout Lines
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Geological Profile showing caves
MONOL ITH
20 ft
Drilling – Grouting Summary
174,666 ft (53,273 m) of overburden drilling
97,032 ft (29,595 m) of rock drilling
290,087 cu ft (8,214.3 m³ ) of injected grout solids.
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1970’S BARRIER WALL CONSTRUCTION
Follow-Up
Two barrier walls installed in Wolf Creek after grouting was completed.
One along Crest
One at down-stream toe
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1970’s Barrier Wall Construction
36”-Rock Drill ICOS Wall
Self-propelled top-drive drill platform
Full-face, roller rock, drill bit
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CURRENT BARRIER WALL CONSTRUCTION
Project Geography
Contractor offices & slurry plant area
Disposal AreaContractor Laydown
USACE Resident office
Power house
Working Platform
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Layout of Wall
• Technique Areas
• Critical Areas
• 3800 linear feet total
THE REQUIREMENTS
Description UnitSpecification Requirements
Barrier Wall Thickness (Minimum) ft 2
Overlap between elements (Minimum) ft 0.5
Concrete strength (Minimum) psi 2000
Permeability (Maximum) Lugeon 3
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WALL CONSTRUCTION SEQUENCE
5-STEP PROCESS
5 – Step Process1. Pre-Grouting (2 lines either side of wall
and intensive grouting in Critical Areas)
2. PCEW (Panel wall embedded to bedrock)
3. Pilot hole drilling (to full depth)
4. Secant pile excavation & Combined barrier wall (to full depth)
5. Verification coring to confirm quality (on selected elements)
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Installation of upstream / downstream grout courtain
High mobility grouting (HMG) to treat the rock more than 5 ft below TOR.
Low mobility grouting (LMG) designed to treat the rock, soft zones of soil, and weathered rock.
2,000 grout holes, most 325 ft deep.
Over 1,000,000 gallons of grout (3.7million liters).
Composite Grout Programs
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Dam Remediation Methodology• 3,800-l.ft Barrier Wall
• 550,000 sq.ft Protective Concrete Embankment
Wall (PCEW)
• 910,000 sq.ft Barrier Wall
• Max depth 275-ft
Protective Concrete Embankment Wall (PCEW)
Construction of a 6-ft wide concrete wall from a working platform to a minimum of 2-ft below the top of the rock.
Installation of 433 primary and secondary concrete panels.
Approx. 550,000 sq.ft of Protective Concrete Embankment Wall (PCEW).
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PCEW Sequence
Embankment
Rock
P
P P
5” min overlap
SP
S
9’-2”
6 ft
Hydromill – With Rock Teeth in Rock
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PCEW Deviation Monitoring
Onboard instrumentation allows for real time monitoring of panel verticality and twist during excavation
Panel report confirms panel position in relation to theoretical
Directionally Drilled Pilot Holes
Installation of 8-inch diameter directionally drilled pilot holes (DD), through the PCEW and full depth into the rock reaching up to 282 ft depth.
Served as a guide for the installation of the secant piles with minimal deviation.
Allow for additional investigation of concrete/rock conditions below the top of the rock.
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DRILL 8” Ø GUIDE/EXPLORATORY HOLES
Embankment
Rock
31”
•Drill 8” Ø guide/exploratory hole through PCEW
•Guide/verticality control for secant pile
•Investigate rock condition at pile location, grout if conditions dictate
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DD – Overlap AnalysisSimulation of primary and secondary piles following pilot holes.
– Starting point for pile installation
DD – Deviation Charts* More than 70% of the pilot holes installed reached a maximumdeviation of 2 to 3 inches at a depth of 282 ft.
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RCD Secant Piles
Installation of 50-inch diameter secant piles, excavated through the PCEW and full depth into the rock reaching up to a target depth of 273 ft, using a Reverse Circulation Drilling machine.
Sequence of primary and secondary piles.
1,197 secant piles installed, with only two remedial piles required.
PRE-EXCAVATION 50” Ø SECANT PILES
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RCD 50” Ø OVERLAPPING SECANT PILES
Embankment
Rock
31” Min. 2’ Overlap req’d
P PS
Protective Concrete Embankment Wall (PCEW)
Hydromill excavation
Overlapping 6’ x 9’ panels
Number of Panels Complete – 245/431
57% Complete
6
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RCD on board instrumentation
Pile Verticality MonitoringEnparis verticality Final Koden run
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Pile Overlap Analysis
Pile verticality information to produce 3D drawings for geometrical analysis
Pile Overlap Analysis
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Combined Barrier Wall Panels
Installation of a wall using a combination of RCD piles and hydromill excavated panels.
50 Inches diameter piles and 9.2-ft x 2.6-ft CBW panels.
52 combined barrier wall elements were installed during the project.
Combined Barrier Wall Panels
50” dia. piles9.2-ft x 2.6-ft CBW panels
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Wolf Creek Dam at construction peak
Deployment of equipment along the alignment of the barrier wall
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PCEW Panel installation in CA#1
Barrier Wall Pile Installation in CA#1
Primary Piles in Cave and Core Trench AreaSecondary Piles in Cave and Core Trench AreaBarrier Wall installed in Cave and Core Trench Area
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Verification Coring on selected elements
179 verification holes were drilled on selected elements to verify the concrete quality, joint quality, the contact with the underlying rock, and permeability.
Geological log, core photos, televiewersurvey, falling and rising head water test, UCS test were performed to verify quality of the barrier wall.
Concrete / Rock Contact
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Televiewer survey in vertical hole
Televiewer survey showing a joint between primary and secondary piles
Wall Completed!
Last pile placed on March 6th, 2013
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Results Quality:
1,197 piles + 52 Combined Barrier Wall elements installed with only 2 remedial piles, les than 0.2%.
Barrier wall thickness, overlap between elements, concrete strength, and permeability requirements met, if not exceeded.
Schedule:
Construction of the Barrier Wall 11 months ahead of schedule.
Safety:
1.3 million hours without a lost time injury.
Wall Thickness Distribution Piles
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Joint Overlap Distribution Piles
Conclusions
Wolf Creek Dam had serious foundation problems due to Karst
The Corps chose a Cutoff Wall as the permanent foundation repair
Treviicos-Soletache used an innovative method of wall construction
Treviicos-Soletache exceeded the Corp’s requirements for the cutoff wall.
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Thank You for your Attention