Dahlia Ponds Tunnel Project Case History
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Transcript of Dahlia Ponds Tunnel Project Case History
DAHLIA PONDS TUNNEL PROJECTCASE HISTORY
Presented By: Nathan Soule, PE, PG Brierley Associates&
Brenden Tippets, Project Executive, BTrenchless
Dahlia Ponds Tunnel Project
OutlineDahlia Ponds Tunnel Project
Owner’s Approach Design & Engineering Construction
Project LocationDahlia Ponds Tunnel Project
Project LocationDahlia Ponds Tunnel Project
Modified Design-BuildDahlia Ponds Tunnel Project
Denver Urban Drainage needed a new approach to tunnel construction Past problems with O’Brian Canal Tunnel
Hired tunneling expert – Brierley Associates (Lyman Henn division)
Retained Qualified Contractor BTrenchless early on
Independent estimator – Bids must be within 10%
EngineeringDahlia Ponds Tunnel Project
Evaluate feasible/allowable methods Subsurface exploration with Contractor
involvement
Test PitsDahlia Ponds Tunnel Project
Cobbles & Boulders Groundwater
Tunneling/Trenchless MethodsDahlia Ponds Tunnel Project
Method Details Advantages Complications
Microtunnel Closed Face• Slurry• EPB
Works for most conditions
High costCobbles < 1/3 TBM dia
Pipe Ramming – Common
Rapid & lost costPenetrates through cobbles
Limited distanceLine & grade deviations
Pipe Ramming – Guided
• Pilot tube• HDD
Accurate line & grade Pilot tube penetrationMultiple up-sizes
Conventional Shield • Sand shelves• Breasting
VersatileAdaptable
Above water tableMed – large dia. only
Open Face TBM Rotating headInexpensive* Limited application
Not well suitedAuger Bore Jacked pipe w/ auger
Ground Improvement • Grouting• Dewatering
Available as supplement
Trial Horizontal Directional DrillDahlia Ponds Tunnel Project
Multiple Attempts
Stopped by cobbles/boulders
Determined guided ram not feasible
Team decided on microtunneling for I-76
Team Effort
Owner •Urban Drainage/ Adams County
Engineer •ICON Engineering/Lyman Henn, a division of Brierley Associates, LLC
Contractor •Btrenchless, a division of BT Construction, Inc.
SUBS •Kelley Dewatering, Garza Concrete, Inlet Structures, Ralph Martinez trucking.
Suppliers •Akkerman, Derrick, Microtunneling, Inc., Wyo-ben, Inc.
Dahlia Ponds Tunnel Project
Project Purpose
BTrenchless completed one 240 LF microtunnel and one 60 ft rescue tunnel.
Design/build of two tunnels for storm sewer, including test pits of existing ground conditions.
240 LF of 54” Tunnel to be completed without disruption of above I-76 highway.
60 LF of 84” rescue Tunnel to be completed online and grade to match existing failed tunnel 30 ft below grade.
Dahlia Ponds Tunnel Project
Dahlia Ponds Tunnel Project
Dahlia Ponds Tunnel Project
Project Scope
Various construction methods used to account for the diverse ground conditions:
Microtunnel Hand Tunnel
Sizes of the installed tunnels ranged from 54” to 84” diameter.
Dahlia Ponds Tunnel Project
Project
Test pit ground conditions
HDD Pilot hole
MTBM (Microtunnel
Boring Machine)Separation Plant
Entry Shafts and Seals
GeneratorsAutomatic Bentonite
Injection System
Dewatering system
Dahlia Ponds Tunnel Project
Microtunnel Machine
AKKERMAN
Microtunnel Boring Machine SL 51 125 HP Head
Dahlia Ponds Tunnel Project
Microtunnel MachineDahlia Ponds Tunnel Project
Microtunnel Machine
Akkerman MC-4 Jacking Frame
Dahlia Ponds Tunnel Project
Separation Plant
DERRICKSeparation Plant
(3) FLC 2000 4-Panel High “G” Shaker Decks
(1) FLC 2000 Mud Cleaner Hydrocyclone System
Dahlia Ponds Tunnel Project
Separation PlantDahlia Ponds Tunnel Project
Separation PlantDahlia Ponds Tunnel Project
Quantifying Material (Onboard Weighing System )
Product Totals Multiple Point Weighing Split Weighing Auto Target Function Auto Tare Function Error Alarms Data Fields Unit Conversion Multiple Batching Modes Tip-off Weighing Zeroing Auto Add Mode Data Analysis Remote Add Button
Dahlia Ponds Tunnel Project
Entry Shafts
GME – Slide Rail System
Dahlia Ponds Tunnel Project
Exit / Entry Seal
Microtunnel Inc. Entry Seals
Dahlia Ponds Tunnel Project
Generators
400 KW Generator 550 KW Generator
(3) 75 KW Generators
Dahlia Ponds Tunnel Project
Automatic Bentonite Injection System
MICROTUNNELING, INC.
Dahlia Ponds Tunnel Project
Dewatering System
Ground water contamination
treatment:
(6) Weir tanks(1) Air Sparging 300 cfm (4) Mezzi air injection
units
Dahlia Ponds Tunnel Project
Known Significant Challenges
Schedule Purchase of Equipment- Short time frame Shaft Construction Contaminated ground water up to 2000 GPM Shallow cover of tunnel under I-76
Dahlia Ponds Tunnel Project
Proposed Solutions
CHALLENGE•Schedule
SOLUTION•Internal weekly meetings•Detailed scheduling•Other existing tunnel
contracts
Dahlia Ponds Tunnel Project
Scheduling
Successful scheduling- project completed 30 days ahead of original schedule.
Provide the owner with feasible schedule in order to anticipate possible changes.
Dahlia Ponds Tunnel Project
Proposed Solutions
CHALLENGE•Purchase of
Equipment
SOLUTION•In-house evaluation of all equipment
needed•Research other industry leaders and their
equipment•Interview other contractors about
performance of the equipment•Date of delivery
Dahlia Ponds Tunnel Project
Dahlia Microtunnel Equipment
Base Microtunnel MTBM #1 MTBM #2 MTBM #3 Separation Equipment MTBM #1 MTBM #2 MTBM #3 Intermediate Jacking Equipment MTBM #1 MTBM #2 MTBM #3
Control Container Slurry Volume Hydraulic Hose
Microtunneling Head Shaker Jacking Force
Steering Head OD Hydrocyclones First Stage Trust Rings
Steering Head Length Excl Cutter Hydrocyclones Second Stage Hydraulic Cylinders
Steering Pressure Unit Size High Pressure Jetting
Number of Steering Cylinders Slurry Tank MTBM #1 MTBM #2 MTBM #3 Jetting Pump
Steering Cylinder Stroke First Chamber Length Jetting Starter Hose
Steering Cylinder Force Second Chamber Length Jetting Tunnel Line
Bypass Valve Overflow Height Bentonite System MTBM #1 MTBM #2 MTBM #3
Drive Motor Guidance System MTBM #1 MTBM #2 MTBM #3 Bentonite Pump
OD Ring Electric Control Box
Power Cable Connections and Extensions MTBM #1 MTBM #2 MTBM #3 Valve and Junction
Stand Alone Unit Tunneling Connections Tunnel Cords
Starter Set Trunk Line Volume
Steering Angle Trunk Line Storage Max Pressure
Computer Hardware Aux Equip Power Cable Pressure Can
Nominal Drive Torque Main Control Cable Supply Can
Trailer Section Length Booster Pump Cable Volume Mixer
Trailer Section OD Hydro Elec Launch Connections Volume Storage
Lead Can Weight Connection Cable Container Electrical Power
Trailer Section Weight Steering Cable Head Power Supply Cable
Cutter Head Weight Extension Hose Hydraulic Bentonite Pipe
Operating Pressure Distance Wheel Auto Bentonite Lube System MTBM #1 MTBM #2 MTBM #3
Slurry Circulation System MTBM #1 MTBM #2 MTBM #3 Emergency Shut Off
Slurry Feed Pump Connection Cable Power Supply Head Entr/Recep Seal for Pipes MTBM #1 MTBM #2 MTBM #3
Slurry Return Pump Drive Motor Cooling
Circulation System Starter Set Purchase Items Training and Service MTBM #1 MTBM #2 MTBM #3
Slurry Line Pipe Jacking Equipment MTBM #1 MTBM #2 MTBM #3 Travel Time
Slurry Line Launching Set Jacking Frame Weekdays
Set of Flow Meter Jacking Pit Overtime and Saturdays
Slurry Container Jacking Force Sundays and Holidays
Length Max Pipe OD
Width Pipe Length
Height Operating Pressure
Inlet Diameter Number of Strokes
Outlet Diameter Jacking Unit Drive
Hydraulic Oil Tank Capacity
Jacking Unit Extension
Proposed Solutions
CHALLENGE•Shoring of wet shafts In
cobble and running sands
SOLUTION•Provide a realistic approach
to anticipated GPM. •Determine best/cost
effective method of construction.
Dahlia Ponds Tunnel Project
Shaft ConstructionDahlia Ponds Tunnel Project
Proposed Solutions
CHALLENGE•Handling of
contaminated ground water
SOLUTION•Discuss potential problems up front
with owner. •Involve state regulatory agency, so
they are aware and will be on-board with potential problems.
•Evaluate most cost effective treatment.
Dahlia Ponds Tunnel Project
Contaminated ground water
Treatment of 2000 GPM system
Treatment of Dissolved Manganese Total Iron Dissolved Iron
Dahlia Ponds Tunnel Project
Proposed Solutions
CHALLENGE•Shallow cover of tunnel
SOLUTION•Lengthen bore to enter
farther down slope•Monitor entry point for
possible settlement
Dahlia Ponds Tunnel Project
Shallow cover
Slurry returning to the surface
Install foam injection to stabilize face
Dahlia Ponds Tunnel Project
Completion of Work
Overall BTrenchless completed the two tunnels in 3 months, including all structures and appurtenances approximately 1 month ahead of schedule
Maintained good relationships with owner, engineers and the community, with little disruptions
Dahlia Ponds Tunnel Project
Lessons Learned
Think outside of the box (never accept “this is how we’ve always done it”)
Practice teamwork and adhere to advice from other industry leaders
Success comes from lessons learned
Dahlia Ponds Tunnel Project
Questions?
Dahlia Ponds Tunnel Project
Phone: 303-286-0202Fax: 303-286-1262
www.BTrenchless.com
Phone: 303-469-0199Fax: 303-466-8309
www.BTConstruction.com
9885 Emporia Street Henderson, Colorado
80640
110 16th St. #700Denver, Colorado
80202
Phone: 303-534-1100Fax: 303-534-1777
www.lymanhenn.com