Reference
Trenchless techniques A–Z
The full ISTT taxonomy — 181 techniques and categories, with descriptions published by the International Society for Trenchless Technology and the ASTT corporate members who deliver them.
181 techniques and categories
A–C
- Aboveground SurveysAboveground surveys can be used to search for evidence of leakage of buried pressure…
- Acoustic MethodsThe simplest of these techniques is simple sounding of the wall with a hammer.
- Acoustic SensorsMonitoring for any acoustic indications of pipe failure is one technique for monitoring…
- Adhesive-backed hoseIn this inserted hose lining variant, the inserted hose is adhered to the host pipe…
- Alignment / Guidancecategory
- Allied TechniquescategoryWhile not generally termed "trenchless technology" these methods also either eliminate…1 paper
- Asset Condition→ now “Asset Condition Assessment”
- Asset Condition AssessmentIn this category are grouped a variety of methods of determining the current condition…10 papers
- Asset EnvironmentcategoryFor both new installation and rehabilitation work on underground utilities, it is…
- Asset LocationFor almost any construction project it is necessary to investigate ground conditions and…6 papers
- Asset TracingcategoryIn this category of methods, are various means of following the path of a known utility…
- Assist Techniquesno ISTT description yet
- AugerAugers may be used as part of a face support system.
- Auger BoringAuger boring is generally used to install steel casing pipe in relatively soft stable…2 papers
- Bent SubIn this system, the drilling mud is pumped to the drill head under pressure where it is…
- CCTVClosed Circuit Television (CCTV) video cameras mounted on small tractor devises or sleds…
- Cement / Mortar LiningCement mortar linings (CML), like other spray-on coatings, are used primarily for…
- CIPP Patch Repair(Also known as CIPP Spot Repair, Part Liner, Patch Liner and Short Liner.)
- Close-fit LiningThis category of renovation covers pipe lining systems that install a new pipe lining…19 papers
- CompositionThe most common resin used today in CIPP is polyester resin, normally an ISO-NPG resin.
- Continuous PipePolyethylene (HDPE and PE) and polyvinyl chloride (PVC) pipes are most commonly used for…
- Continuous PipePolyethylene (HDPE and PE) and polyvinyl chloride (PVC) pipes are most commonly used for…
- Conventional TunnelingConventional bored tunneling (but not cut-and-cover tunneling) is a “trenchless”…
- ConveyorConveyor belt spoil removal systems are possible in person-entry tunnel diameters.
- Crawler PlatformCrawler platforms (especially for CCTV systems) are widely used for inspection of…
- Cured-in-place Lining (CIPP)→ now “Cured-in-Place Pipe (CIPP)”
- Cured-in-Place Pipe (CIPP)Cured in Place Pipe (CIPP) can be used to rehabilitate gravity sanitary sewers, storm…15 papers
- Curing ProcessThe uncured resin is designed so that, once the liner has been installed, the curing…
- Curved / GyroscopicFor curved microtunnelling, gyroscopic systems may be used - involving a north-seeking…
D–F
- Deployment MethodscategoryInspection techniques may be deployed in a variety of ways, e.g. using a conventional…
- Depth / ElevationStructurally, the groundwater level at a site controls the external groundwater pressure…
- Direct Steerable Pipe Thrusting (DSPT)Direct Steerable Pipe Thrusting (DSPT) is a trenchless method where a thruster pushes a…7 papers
- Discrete Stress-Strain SensorsDiscrete stress-strain sensors can be used for special monitoring applications within…
- Drill and BlastDrill and blast tunnelling is used for tunnelling in rock.
- Drilling/Steering Mechanismcategory
- DroneDrone-based camera and laser surveying systems are recent additions to the options for…
- Earth-Pressure Balance (EPB)In the earth-pressure balance (EPB) system, the excavation face is supported by matching…
- Electrical TomographyElectrical or electromagnetic tomography uses geometrically-spaced measurements to infer…
- Electromagnetic EnvironmentcategoryThe electromagnetic environment encompassing a planned or existing buried utility can be…
- Electromagnetic MethodsA variety of electromagnetic methods have been developed for the assessment of condition…
- Existing Pipe DisplacedcategoryPipe bursting and pipe splitting are trenchless methods used to replace existing…4 papers
- Existing Pipe RemovedcategoryIn this category of pipe replacement, the existing pipe is removed as part of the…
- Expander / Hammer Configurationno ISTT description yet
- External Void DetectionThe detection of external voids can be very important in assessing the structural…
- Face Supportcategory
- Fiber Optic SensorsFiber optic sensors can provide extremely sensitive sensor systems that are suitable for…
- Float / SubmersibleIn partially filled pipes or tunnels, floating platforms can be used to allow the…
- Flood GroutingIn the flood grouting method, a section of sewer system consisting of a mainline between…
- Flow Quality (Chemical / Biological)The presence of infiltration in significant quantities may alter the chemical and/or…
- Flow Quantity MonitoringSignificant leakage in pressure pipe systems may be detected by discrepancies in flow…
- Fold-and-FormIn this category are close-fit linings that use both heat and pressure to change the…
- Fully-independent RehabilitationSince many of the methods listed as "renovation" techniques are capable of being…1 paper
G–H
- Geochemical SurveyGeochemical surveys are used to look for chemical elements or materials in the…
- Geophysical SurveyAn important category of non-invasive site investigation techniques involves geophysical…
- Ground InvestigationMost of the methods identified here are part of typical site investigation work for any…
- Ground Penetrating Radar (GPR)There are a wide range of techniques available to locate buried pipes.2 papers
- Ground Penetrating Radar (GPR)There are a wide range of techniques available to locate buried pipes.
- Groundwater MonitoringGroundwater conditions at a site are important in both the design and construction of…
- Grout-in-Place HoseIn this category, a flexible liner is used that typically is made from a plastic sheet…
- Grout-in-place Sheet Lining→ now “Grout-in-Place Hose”
- Guidancecategory
- Horizontal Directional Drilling (HDD)HDD is an extremely versatile trenchless technology that is used for the installation of…28 papers
- Hybrid MethodscategoryAs the name implies, hybrid methods combine elements of two or more trenchless methods…7 papers
I–K
- Impact MolingThe impact mole or piercing tool is one of the oldest and simplest of the trenchless…
- Impressed Signal TechniquesThe methods grouped as impressed signal techniques all involve tracing the…
- In-pipe Camera ObservationDirect observation of an active leak or observation of evidence of prior leakage using…
- In-pipe GPRIn-pipe GPR is a pipe wall and ground penetrating radar system that is specifically…
- Infiltration / Inflow (Gravity Pipes)Infiltration/ Inflow (I/I) can be defined as the process by which storm water or ground…
- Infrared ScanningInfrared scanning of the wall of a pipe or tunnel can show information about any changes…
- Infrared ScanningInfrared scanning of the wall of a pipe or tunnel can show information about any changes…
- Infrared ScanningInfrared scanning of the wall of a pipe or tunnel can show information about any changes…
- Inserted Hosecategory3 papers
- Inserted LinercategoryThis category covers all the types of liners that are inserted into the existing pipe…26 papers
- Inserted Pipecategory
- Inserted Seals→ now “Mechanical Seals”
- Insertion ProcessThe first CIPP liner installed in London in 1971 was pulled into position within the…
- Inspection ApplicationcategoryThe choice of inspection methods is significantly affected by the purpose of the…
- Internal Survey TechniquesInternal survey techniques for tracing the vertical and horizontal alignment of buried…
- Investigation / AssessmentcategoryIn addition to the work undertaken to actually install or rehabilitate an underground…18 papers
- Joint GroutingGrouting can reduce or eliminate inflow and infiltration of sewer lines and manholes by…
- Keyhole DrillingThe Keyhole Drilling method uses the trenchless techniques of coring, potholing and…
L–M
- Laser / LIDARThe detailed pipeline dimension can be obtained by the laser profiling in open pipes and…
- Lateral / Small Pipe InspectionSmall pipe inspection can be accomplished using nozzle cameras that are pushed through…
- Lateral Junction CIP Repair(Also known as CIP(P) Lateral Connection Repair, Connection Liner, Cured in Place…
- Leak Detection (Pressure Pipes)There are a number of methods for surveying and locating leaks in pressurized pipes.
- Leak Signature DetectionThe most common leak signature detection method tracks the acoustic signature of a leak…
- Loose-fit or Close-fit LiningcategorySome lining approaches may be designed to be loose-fit or close-fit according to project…7 papers
- Mainline Pipe / Tunnel InspectionThe most common visual pipe inspection devices are Closed Circuit Television (CCTV)…
- Manhole / Chamber InspectionManhole/chamber inspection can be accomplished using person-entry techniques but, to…
- Manhole RehabilitationWhile not generally termed “trenchless technology”, manhole rehabilitation methods use…1 paper
- Maxi-HDDMaxi HDD involves large-scale equipment for long-distance and/or large diameter…
- Mechanical→ now “Swaged Lining”
- Mechanical SealsMechanical seals are available to repair pipe defects at joints or over short distances…
- Melt-in-Place-Pipe (MIPP)In this category of close-fit lining, a principally thermal approach to creating the…
- Method scalecategoryAs indicated in the general method description, HDD principles are used for…
- Midi-HDDAs the name implies, midi-HDD represents a mid-range of applications for HDD.
- Mini-HDDMini-HDD represents the smallest scale of HDD applications involving compact equipment…
- Mini-trench / Micro-trenchGenerally mini-trench and micro-trench methods of underground pipe or cable installation…1 paper
- Mole PloughingMole ploughing and narrow trenching are not trenchless technologies but they both create…
- Muck CartA muck cart is a traditional way of moving excavation spoil from the tunnel face to the…
N–O
- New InstallationcategoryThis class of methods is focused on the installation of new utilities using directional…58 papers
- Non-adhered hoseIn this inserted hose lining variant, the inserted hose is laid loosely within the host…
- Non-Person-EntryA non-person-entry scale for pipe jacking represented an important part of the…
- Non-structural (Sealing)categoryIn this category of repair, the target for the rehabilitation of the host pipe is to…
- Nozzle CameraA nozzle camera is a camera placed at the front of a rod or cable such that is can be…
- Nuclear MethodsAs the name implies, nuclear methods use radiation sources to gather information about…
- Nuclear MethodsAs the name implies, nuclear methods use radiation sources to gather information about…
- Operational Performance AssessmentcategoryObviously, the operational performance of a system is strongly connected to the physical…
- OtherParticularly in person-entry-scale pipe jacking, a variety of other face support…
- Other Close-fit LiningcategoryIn this category, various other types of close-fit linings are described.2 papers
- Other MethodsThere are a variety of other forms of surface-based investigation for locating buried…
- Other TechnologiesFor further information about the wide range of tunnelling technologies and their…
- Overflow DetectionOverflows from sewer systems may occur at designed overflow points in older combined…
P–Q
- Panel Lining(Other names for longitudinally short liners include sectional lining, discrete lining…1 paper
- Person-EntryPerson-entry scale pipe jacking provides more options to address problems that may occur…
- Pilot Tube Assist TechnologiesA variety of hybrid methods incorporate the use of a pilot tube to establish an accurate…
- Pipe BurstingPipe bursting is a trenchless method used to replace existing pipelines in the same…3 papers
- Pipe EatingPipe eating uses a microtunneling type machine to crush and “excavate” the existing pipe…
- Pipe ExtractionPipe extraction is a trenchless method, which can remove an existing pipe for disposal…
- Pipe Fracture Mechanismcategory
- Pipe Jacking / MicrotunnellingPipe jacking is a tunneling method where a pipe being installed is used also as ground…27 papers
- Pipe RammingPipe ramming is a trenchless method for installing steel casing pipe under roads…
- Pipe ReamingPipe reaming is a trenchless method that removes the host pipe while at the same time…
- Pipe SplittingPipe splitting is a trenchless method used to replace existing pipelines in the same…1 paper
- Pneumatic / Hydraulic HammerA pneumatic hammer device was the original pipe bursting device used in the UK for…
- Polymeric Coating / LiningPolymeric (thermosetting) coatings and liners (notably epoxy, polyurethane (PU) and…
- Potholing→ now “Potholing/Keyholing, Coring, Vacuum Excavation”
- PotholingSometimes it may be effective to perform potholing techniques to locate or inspect an…
- Potholing for Local RepairWhere suitable internal repairs are not possible, it may be necessary to access the pipe…
- Potholing Repair→ now “Potholing for Local Repair”
- Potholing/Keyholing, Coring, Vacuum ExcavationPotholing or keyholing is a method of accessing underground infrastructure with minimal…3 papers
- Precise Coordinatesno ISTT description yet1 paper
- Preliminary InspectionDue to the extent of buried infrastructure assets to be inspected and managed and the…
- Pressure Monitoring and DetectionDifferential pressure monitoring in different parts of a pipeline system may show up…
- Push-Pull Satellite CameraInspection cameras for smaller diameter pipes or laterals are often simply pushed…
- QualityGroundwater quality in terms of its chemical and biological constituents can be…
R–S
- Ram-assist TechnologiesIn this group of hybrid methods, trenchless drilling or tunnel boring or pipe…
- Ramming / ImpactcategoryThis subset of methods uses an impact or hammering approach to advance a pipe through…
- Reduced Surface DisturbancecategoryIn this category are methods that do create a continuous disturbance to the ground…1 paper
- RehabilitationcategoryThis class of methods is focused on the rehabilitation of existing utility pipes to…43 papers
- Reinforcementno ISTT description yet
- RenovationcategoryThere are many trenchless renovation methods that have been developed in the past…38 papers
- Renovation / Repaircategory38 papers
- Renovation Slip LiningSlip lining with an inserted pipe used for “renovation” purposes may utilize the same…7 papers
- RepaircategoryThe term “repair” is used here to denote methods that are targeted at local defects in a…
- ReplacementcategoryThe term “replacement” is used here to denote that a new pipe (or the full equivalent of…5 papers
- Replacement Slip LiningIn this replacement application a new pipe of smaller outside diameter than the inside…
- Resistivity MeasurementsResistivity measurements between different points on the ground surface or between…
- Robotic RepairsRobotic systems play a significant part in trenchless technology construction.
- Robotic Spot Repair→ now “Robotic Repairs”
- Rolled Down LiningIn this category of close-fit linings in which the plastic lining pipe (typically…
- Seismic / Sonar TechniquesThe term "sonar" is typically used when a sound (compression) wave is propagated in…
- Short Liner / Connection Liner→ now “CIPP Patch Repair”
- Site InvestigationSite investigation is an important precursor to most construction projects - whether…8 papers
- Sizecategory
- Slant-face drill bitThe most common steering mechanism involves a slant-face drill bit, the orientation of…
- SlurryPumping a mud slurry to the face chamber in a microtunnelling machine both allows the…
- Smoke and Dye / Smoke and Dye Testing→ now “Smoke and Dye Testing”
- Smoke and Dye TestingDye testing is used to determine if surcharge in a drainage system area is in fact…
- Soft-ground ShieldIn a typical project, a soft-ground shield is a tunnel technique that uses a steel…
- Soil SamplingSoil sampling is an important part of the site/ground investigation process.
- Soil/Rock TBMA large proportion of tunnel projects are excavated by a Tunnel Boring Machine or TBM.
- SondeA walk-over tracking system is used to help guide and monitor the location of the bore.
- Sonde TechniquesA sonde device can be added to a push camera system, CCTV platform or a separate device…
- Spiral-WoundSpiral wound liners can be used to rehabilitate gravity pipeline applications such as…2 papers
- Spoil Handlingcategory2 papers
- Static PullStatic pull systems for pipe bursting do not include the use of pneumatic hammers to…
- Straight / LaserFor bores with a straight alignment, the standard method of guidance for microtunnelling…
- StructuralcategoryIn this category are localized repair techniques, that enhance or replace the structural…
- Structural Condition AssessmentcategoryAn important part of the assessment of asset condition is to determine the current…
- Structural Response SensorsThis category covers a wide potential range of sensors that may be used to determine the…
- Surface-applied LiningSurface-applied linings are considered to include linings that are sprayed, spin-cast…7 papers
- Surface-based TechniquescategoryThese methods are aimed at general searching for the presence of unknown buried…2 papers
- Swaged LiningIn this category are close-fit linings in which the plastic lining pipe (typically…
- System Flow MonitoringSystem flow information relative to rainfall events and reports of overflows/backups…
T–Z
- TechniquescategoryIn this category are placed the types of equipment used to carry out the inspection.
- Thermal→ now “Melt-in-Place-Pipe (MIPP)”
- Thermal EnvironmentcategoryThe thermal environment conditions that can affect trenchless utility projects can…
- Thermal-Mechanical→ now “Fold-and-Form”
- Trenchless InstallationscategoryThis group of methods comprise the core of what are considered “trenchless” new…57 papers
- Troweled or Sprayed Structural LiningTroweled or sprayed fully-structural linings are essentially coatings that have…
- Ultrasound MethodsUltrasound methods use high frequency sound waves to penetrate a pipe wall.
- Vacuum ExtractionThe excavated material at the face may be transported to the surface using a high…
- Valves, Safety Equip, AppurtenancesUnderground utility systems contain a wide variety of operating components and…
- Visual/Laser InspectionWhile person entry viewing is possible for larger underground assets, most underground…
- Wall Condition / ThicknessTechniques for assessing the wall condition and/or thickness from inside a pipe or…
- Wall Impact MethodsWall impact methods can be as simple as hitting the wall of a tunnel with a hammer and…
- WirelessFor deep bores, the most common tracking method uses a “wireline” to connect a tracking…
- WirelineAs a borehole depth increases, sonde methods eventually become ineffective (depending on…
- With Pipe SegmentsIn gravity sewer renovation applications, an important advantage of this form of slip…
- With Pipe SegmentsIn gravity sewer renovation applications, an important advantage of this form of slip…
- Within Existing PipecategoryTwo main approaches are included in this form of replacement application.1 paper
- Zoom CameraA typical zoom camera system involves a camera installed on a mast that can be lowered…