Dahlia Ponds Tunnel Project. Presented By: Nathan Soule, PE, PG Brierley Associates & Brenden Tippets, Project Executive, BTrenchless

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1 DAHLIA PONDS TUNNEL PROJECT CASE HISTORY Presented By: Nathan Soule, PE, PG Brierley Associates & Brenden Tippets, Project Executive, BTrenchless

2 Outline Owner s Approach Design & Engineering Construction

3 Project Location

4 Project Location

5 Modified Design Build 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%

6 Engineering Evaluate feasible/allowable methods Subsurface exploration with Contractor involvement

7 Test Pits Cobbles & Boulders Groundwater

8 Tunneling/Trenchless Methods Microtunnel Method Details Advantages Complications Closed Face Slurry EPB Works for most conditions High cost Cobbles < 1/3 TBM dia Pipe Ramming Rapid & lost cost Limited distance Common Penetrates through Line & grade deviations cobbles Pipe Ramming Pilot tube Accurate line & grade Pilot tube penetration Guided HDD Multiple up-sizes Conventional Shield Sand shelves Breasting Versatile Adaptable Above water table Med large dia. only Open Face TBM Rotating head Auger Bore Jacked pipe w/ auger Inexpensive* Limited application Not well suited Ground Improvement Grouting Dewatering Available as supplement

9 Trial Horizontal Directional Drill Multiple Attempts Stopped by cobbles/boulders Determined guided ram not feasible Team decided on microtunneling for I 76

10 Team Effort Owner Engineer Contracto r SUBS Suppliers Urban Drainage/ Adams County ICON Engineering/Lyman Henn, a division of Brierley Associates, LLC Btrenchless, a division of BT Construction, Inc. Kelley Dewatering, Garza Concrete, Inlet Structures, Ralph Martinez trucking. Akkerman, Derrick, Microtunneling, Inc., Wyo ben, Inc.

11 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 thexisting iti fildt failed tunnel 30 ft below grade.

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14 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.

15 Project Test pit ground conditions Generators Automatic Bentonite Injection System HDD Pilot hole Entry Shafts and Seals Dewatering system MTBM (Microtunnel Boring Machine) Separation Plant

16 Microtunnel Machine AKKERMAN Microtunnel Boring Machine SL HP Head

17 Microtunnel Machine

18 Microtunnel Machine Akkerman MC 4 Jacking Frame

19 Separation Plant DERRICK Separation Plant (3) FLC Panel High G Shaker Decks (1) FLC 2000 Mud (1) FLC 2000 Mud Cleaner Hydrocyclone System

20 Separation Plant

21 Separation Plant

22 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

23 Entry Shafts GME Slide Rail System

24 Exit / Entry Seal Microtunnel Inc. Entry Seals

25 Generators 400 KW Generator 550 KW Generator (3) 75 KW Generators

26 Automatic Bentonite Injection System MICROTUNNELING, INC.

27 Dewatering System Ground water contamination treatment: (6) Weir tanks (1) Air Sparging 300 cfm (4) Mezzi air injection units

28 Known Significant Challenges Shdl Schedule Purchase of Equipment Short time frame Shaft Construction Contaminated ground water up to 2000 GPM Shallow cover of tunnel under I 76

29 Proposed Solutions CHALLENGE Schedule SOLUTION Internal weekly meetings Detailed scheduling Other existing tunnel contracts

30 Scheduling Successful schedulingproject completed 30 days ahead of original schedule. Provide the owner with feasible schedule in order to anticipate possible changes.

31 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

32 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 Width Height Inlet Diameter Outlet Diameter Max Pipe OD Pipe Length Operating Pressure Number of Strokes Jacking Unit Drive Hydraulic Oil Tank Capacity Jacking Unit Extension

33 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.

34 Shaft Construction

35 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.

36 Contaminated ground water Treatment of 2000 GPM system Treatment of Dissolved Manganese Total Iron Dissolved Iron

37 Proposed Solutions CHALLENGE Shallow cover of tunnel SOLUTION Lengthen bore to enter farther down slope Monitor entry point for possible settlement

38 Shallow cover Slurry returning to the surface Install foam injection to stabilize face

39 Completion of Work Overall llbtrenchless completed the two tunnels in 3 months, including all structures andappurtenances appurtenances approximately 1 month ahead of schedule Maintained good relationships with owner, engineers and the community, with little disruptions

40 Lessons Learned Think outside of the box (never accept hi this is how we ve always done it ) Practice teamwork and adhere to advice from other industry leaders Success comes from lessons learned

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42 9885 Emporia Street th St. #700 Henderson, Colorado Denver, Colorado Phone: Phone: Phone: Fax: Fax: Fax: com com