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Pipejacking method• Closedfaceshield usingslurry to remove excavatedsoil• Positive face support inunstable soils and undergroundwater• Remotecontrolled;no manentry• Can be stopped by largequantities of cobbles or largerocks• Steerable• Many jacking pipe options• Diameters: 24” – 90”
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Copyright 2005 NASTT
Microtunneling Microtunneling
Best Practices
Quality Assurance / Quality Control
Best Practices
Quality Assurance / Quality Control
Microtunneling • Pipejacking method • Closedface shield using slurry to remove excavated soil
• Positive face support in unstable soils and under groundwater
• Remotecontrolled; no man entry
• Can be stopped by large quantities of cobbles or large rocks
• Steerable • Many jacking pipe options • Diameters: 24” – 90”
Quality Assurance Approach Quality Assurance Approach • Prequalify contractors for difficult projects • MTBM must be compatible with ground conditions • Use specialty trenchless construction management • Specifications (if you don’t specify it, it won’t get done)
• Microtunneling • Slurry Disposal • Lubrication • Intermediate Jacking Stations (IJS) • Entry/Exit seals
• Shaft Construction • Pipe Material • Settlement Monitoring • Contact Grouting • Ground Improvement (where necessary)
• Prequalify contractors for difficult projects • MTBM must be compatible with ground conditions • Use specialty trenchless construction management • Specifications (if you don’t specify it, it won’t get done)
• Microtunneling • Slurry Disposal • Lubrication • Intermediate Jacking Stations (IJS) • Entry/Exit seals
• Shaft Construction • Pipe Material • Settlement Monitoring • Contact Grouting • Ground Improvement (where necessary)
Pipe Materials Pipe Materials • Reinforced Concrete • Steel • Fiberglass • Polymer Concrete • Clay • Ductile Iron
• Reinforced Concrete • Steel • Fiberglass • Polymer Concrete • Clay • Ductile Iron
Material Quality Control Material Quality Control • Pipe material consistent with soil conditions, surface and installation loads, pressure and corrosiveness
• Pipe manufactured according to ASTM, AWWA standards
• Important dimensional tolerances • Roundness • Straightness • Consistent diameter
• Must have flush joints • Must evenly transmit jacking loads • Lubrication/grout ports • After installation check for line and grade accuracy and damage to pipe or lining
• Pipe material consistent with soil conditions, surface and installation loads, pressure and corrosiveness
• Pipe manufactured according to ASTM, AWWA standards
• Important dimensional tolerances • Roundness • Straightness • Consistent diameter
• Must have flush joints • Must evenly transmit jacking loads • Lubrication/grout ports • After installation check for line and grade accuracy and damage to pipe or lining
Microtunneling Process Microtunneling Process Jacking Shaft 26 x 16 feet typical
Sheet Piles Soldier Piles and Lagging
Auger Drilled (≤20’ diameter) Caissons
Reception Shaft 16 x 14 feet typical
Sheet Piles Soldier Piles and Lagging
Trench Box Auger Drilled
Pipe Material Options Reinforced Concrete
Hobas Polymer Concrete
Steel casing or carrier Clay
Ductile iron
Hydraulic Jacks
Jacking Shaft
Soil Removed
With
Slurry
Receptio
n Sh
aft
Microtunneling Process Microtunneling Process
Machine is
Rem
oved
Construction Duration Jacking Shaft (30’ deep)
2 – 4 weeks
Reception Shaft (30’ deep) 1 – 3 weeks
Reception shafts can be plated until retrieval of MTBM
Microtunneling (per drive) Setup – 10 days
Progress – ~30ft/dayclay; 60 ft/day sand 600’ – 20 days 1300’ – 45 days Retrieval – 5 days
Microtunneling Process Microtunneling Process Equipment
Control Container Generator
Soil Separation Plant Slurry Tanks
Lubrication Plant Pipe Storage
Crane Loader
Dump Truck
Site Preparation Site Preparation • Locate and visually confirm utilities • PreConstruction Survey (damage and settlement baseline)
• Traffic Control • Spoil Handling and Disposal • Shaft Construction and Safety
• Perimeter Fencing • Traffic Plates or Safety Netting • Tag In/Out for Shaft Entry
• Safety
• Locate and visually confirm utilities • PreConstruction Survey (damage and settlement baseline)
• Traffic Control • Spoil Handling and Disposal • Shaft Construction and Safety
• Perimeter Fencing • Traffic Plates or Safety Netting • Tag In/Out for Shaft Entry
• Safety
Quality Control During Installation
Quality Control During Installation
• Proper shaft construction
• Thrust block perpendicular to drive
• Laser mounted independent from shaft elements and jacking frame
• Proper shaft construction
• Thrust block perpendicular to drive
• Laser mounted independent from shaft elements and jacking frame
Installation Issues Installation Issues
• Good shaft workmanship • Groundwater controlled, no soil entering shaft
• Maintain line and grade tolerance and limit steering rate to 1:250
• Exit/entry seals • Match excavation rate to penetration rate and soil conditions (no overexcavation or underexcavation)
• Good shaft workmanship • Groundwater controlled, no soil entering shaft
• Maintain line and grade tolerance and limit steering rate to 1:250
• Exit/entry seals • Match excavation rate to penetration rate and soil conditions (no overexcavation or underexcavation)
Microtunneling Inspection Microtunneling Inspection
• Prelaunch inspection of MTBM
• Take measurements multiple times per pipe • Machine drive records • Bag samples of soils from separation plant
• Problems, unusual observations
• Settlement monitoring records
• Prelaunch inspection of MTBM
• Take measurements multiple times per pipe • Machine drive records • Bag samples of soils from separation plant
• Problems, unusual observations
• Settlement monitoring records
Drive Completion Drive Completion • Control soil and groundwater during MTBM retrieval
• Check pipe for proper line and grade
• Test pipe for joint integrity, design pressure
• Construct manholes/junction structures
• Backfill/abandon shafts • Restore ground surface • Air test and video inspect line upon completion
• Control soil and groundwater during MTBM retrieval
• Check pipe for proper line and grade
• Test pipe for joint integrity, design pressure
• Construct manholes/junction structures
• Backfill/abandon shafts • Restore ground surface • Air test and video inspect line upon completion
Consequences of Poor Practices! Consequences of Poor Practices! • Stuck MTBM • Damaged MTBM • Line and Grade Errors • Broken Pipe • Shaft Failures • Settlement / Heave
• Stuck MTBM • Damaged MTBM • Line and Grade Errors • Broken Pipe • Shaft Failures • Settlement / Heave
For Further Information on Microtunneling Equipment & Operations Please Visit
For Further Information on Microtunneling Equipment & Operations Please Visit
Booth 226 & 228 Booth 428 & 430
Booth 615 Booth 208
Booth 623 & 722
Booth 212
Schauenburg MAB GMBH
Booth 327
For Further Information on Jacking Pipe Please Visit For Further Information on Jacking Pipe Please Visit
Booth 626 & 628 Booth 418
Booth 311 Booth 309
Booth 721 Booth 303
Booth 517
Booth 527
Booth 400
Booth 630
Booth 202
For Further Information on Pumping Equipment & Operations Please Visit
For Further Information on Pumping Equipment & Operations Please Visit
Booth 101 Booth 316
Booth 410
Booth 500
For Further Information on Lubricants, Grouting & Sealing
Please Visit
For Further Information on Lubricants, Grouting & Sealing
Please Visit
Booth 313
Booth 301
Booth 416