introduction to trenchless · pdf filepulse induction ground penetrating ... trenchless...

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Introduction toTrenchless Technology

Continuous Trenching

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Old roads, old pipes ?

• Superb construction• Little maintenance • Low operational costs

• When to rehabilitate?

JACK

New roads, old pipes?

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We are not alone!

Jack appears in different figures!

………but mostly not at the same time!

Jack’s appearance

Needs to be • Minimized or banished

• Find other ways of rehabilitation• Less damage to pavement• Less inconvenience to customers

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Solution to JACK

Trenchless Technologies

Trenchless Technology

Techniques for utility line installation, replacement, rehabilitation, inspection, location and leak

detection,with minimum excavation from the ground surface.

North American Society of Trenchless Technology (NASTT)

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Key PointsMinimal surface excavation

Alternative to open cut excavation

Can have entrance and exit surface excavations – JACK!!!!

Pipelines usually have diameters less than 900 mm (36 inches) - non person entry

Key Points (Continued)Typically considers only urban utilities:

Water and wastewater systemsGas, petroleum and chemical pipelines Electrical and communications networksAccess ways and other small diameter tunnels

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Excludes: Large tunnels (< 1%)

Chunnel

World largest tunneling machine(14.2 m in diameter)

people

Method ClassificationMany classification systems proposedNo industry standardGenerally TT methods classified into four broad categories

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Broad Categories

TrenchlessTechnologies

ConditionAssessment

On-lineReplacement

RehabilitationRepair

NewInstallations

LocatingMapping

AssetManagement

New Installations

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New Installations

NewInstallations

Non-SteeringMethods

SteeringMethods

MolingPipe RammingAuger Boring

MicrotunnellingHorizontal Directional Drilling

Pipe Jacking

On-line Method

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On-line MethodPipe bursting

Gravity Pipesvitrified clay, brick, concrete, steel, ductile & cast iron, asbestos cement (transite), pitch fibreHDPE,PVC etc..

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Pressure PipesPrestressed Concrete Cylinder Pipes (PCCP)

AWWA C301 and C303, lined, embedded core, bar wrapped

SteelIron (cast and ductile)Asbestos cement (transite)Wood (solid and stave)HDPEPVCetc..

Pipe MaterialsNon-metallic

Wood stave pipePolyethylene

MDPEHDPE

PVCConcretePolymer concreteAsbestos cementPitch fibre

MetallicCast ironDuctile ironCopperSteelPCCP

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Pipeline AccessGRAVITY Pipelines

Partial pipe flow Interior access readily available by person, camera, and non destructive testing (NDT) toolsPipeline inspection performed live or off line

Pressure PipelinesFull pipe flowTypically small diameter than gravity pipelinesInterior access limited (pressure, contamination and disinfection)Interior inspection usually requires pipe Sto be taken off line

Pipeline Condition AssessmentPipe condition rating

Deterioration state?Video camera imaging (CCTV)Acoustic methodsMagnetic methods

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SaharaSahara®®: System: SystemReal Time Data ProcessingReal Time Data Processing

Exact LocationsExact Locations

Corroded Wires & CylinderCorroded Wires & Cylinder

Unknown Leak!

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Common Pipe DeteriorationMetallic pipe

Corrosion (reduced pipe wall thickness)

Micro cracks in welds

Leaking joints

Non-metallic pipeCracks FracturesDeformationCollapse

TRENCHLESS PIPELINE REPAIR

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Trenchless Pipeline Repair

GOALReturn a defective pipeline to

a serviceable condition without replacement

How you reach that goal is the key!

Lining - Technologies

Cured-in-Place Pipe (CIPP)

Main Line

Close-Fit Lining

Slip Lining Spray on

Proprietary Technologies

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CIPP

Before

After

Close Fit Lining

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Slip Lining

Rehabilitation

Cement mortarEpoxy

Spray on linings

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Water and Sewer By-Pass

Trenchless Technologies

Tools in a Tool box

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GrowingTrenchlessIndustry Water

Sewer2005

2004

2005

2004

Water

Sewer

REHAB

NEW

Municipal Survey Results

4.28/5.0

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Where are those utilities?

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Gas Main in a Sewer Lateral

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Clearing a Lateral Blockage?

Utility Location and Mapping

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Pipe line location“As built” or “As Recorded” drawings

Not accurateOften do not know where it is

(plan or depth)Cost of not knowing:

Line hitsIncreased construction costs

Subsurface Utility Engineering (SUE)

Pipe line locationCost of not knowing:

Line hitsIncreased construction costs

Subsurface Utility Engineering (SUE)

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Cost of Not Knowing

Basic Tenets of SUESUE Quality Levels

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ASCE Standard GuidelineASCE Standard Guideline

Quality Level “D”

Utility Contact PhaseRecords Research

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Quality Level “C”(Visible Features)

Quality Level “B”

Determine Horizontal Alignment

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Typical QL-B Designating ProjectElectromagneticMagnetometerResonant SonicsAcousticalPulse InductionGround Penetrating Radar

Typical GPR Survey0 -

10 -

20 -

30 -

Tim

e (n

s)

0 10 20Position (m)

Utility

Soil fill horizon

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Quality Level “A”Utility ExposedAccurate X,Y, Z LocatingSize, Material and Condition

Utility Locating

Survey/Data ManagementConventionalGPSSUMGIS

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Mobile GIS?

Utility Locating Quality Level “A”Non-Destructive ExcavationAir/Water & Vacuum Units

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Existing Water and SUE Data

Existing Water and SUE Data

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Existing Water and SUE Data

What is Cost of Not Knowing?Studies show that there is a payback of at

least $4.00 for every $1 spent on SUE.Reduced construction delaysImproved asset operation maintenance and planningEffective spending of rehabilitation $$:

One Ontario relined cement mortar pipe beside it was labeled on GIS system as unlined DI.Liner wrinkled and had to be removed

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Trenchless Technologyvs.

Open cut excavation

Social CostsEconomic:

Traffic disruptionPedestrian disruptionCommercial and business disruption

Environmental:Noise and vibration

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Social Costs (con’t)Safety

Worker safetyEmergency service access

Indirect costsLoss of residual life of adjacent utilities and pavement structures

Social Costs

Not traditionally included in construction costsSometimes difficult to quantify or specifyBecoming more relevant for rehabilitation and construction in urban areas

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Social Costs

Social Costs

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Environmental Costs

Typical Urban Project Costs

Restoration

75%

Materials 5%

Construction

20%

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Typical Urban ProjectSocial costs savings

Traffic delays (cars & people)Economic loses (business)

EnvironmentalNoiseGreenhouse gases

Public perception

Advantages of TT

New installationsFaster pipe installationEnvironmentally friendly???Lower social costsLess labour intensiveLower green house gas emissions?Deeper services

RehabilitationLimited excavationFastLow social costsLine remains in serviceLower construction cost???

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TT LimitationsNew construction

Limited contract specifications availableInstallation impact on pipe or other buried structures??Contractor experience

Who takes the risk?

RehabilitationQuality assurance

Materials, construction

Industry marketingInstallation cost?Inspection techniquesDesign techniquesFailures - cost of not knowing