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Papers, case studies, standards and webinars covering trenchless methods across Australia and New Zealand.
459 results (298 ASTT documents, 161 ISTT technique descriptions) · showing 433–456
Sonde
A walk-over tracking system is used to help guide and monitor the location of the bore. The system is comprised of a transmitter and receiver. The transmitter or sonde is located in a housing unit near the front of the drill string. The transmitter emits a continuous magnetic signal, which is picked up by a…
ISTT
Sonde Techniques
A sonde device can be added to a push camera system, CCTV platform or a separate device to allow tracking of the horizontal location and approximate depth of an existing pipe. A walk-over tracking system is used in conjunction with the sonde. The transmitter or sonde moves along the pipe. The transmitter emits a…
ISTT
Spiral-Wound
Spiral wound liners can be used to rehabilitate gravity pipeline applications such as storm sewers, sanitary sewers, conduits, culverts and process pipes. Spiral wound linings comprise several allied but distinct approaches to creating a liner pipe or a structural lining within an existing host pipe or tunnel. The…
ISTT
Static Pull
Static pull systems for pipe bursting do not include the use of pneumatic hammers to effect the bursting process. The bursting is accomplished using the splitting force created by the pulling of the slanted bursting head into the existing pipe. Cables or quick connect rod systems are used to provide the tensile pull.…
ISTT
Straight / Laser
For bores with a straight alignment, the standard method of guidance for microtunnelling is the use of a laser beam set in the starting shaft and a target placed towards the rear of the microtunnelling machine. The target may be an "active" target responding to the laser light hitting the target or a "passive" target…
ISTT
Structural
In this category are localized repair techniques, that enhance or replace the structural function of the existing host pipe or connection. They may be targeted at deteriorated connections (e.g. between laterals and the mainline) or at a localized section of pipe that is damaged while the rest of the pipe is in good…
ISTT
Structural Condition Assessment
An important part of the assessment of asset condition is to determine the current structural adequacy of the utility, to try to predict its remaining service life and, if necessary, to determine suitable methods for its rehabilitation or replacement. These methods examine the wall condition (pipe material condition,…
ISTT
Structural Response Sensors
This category covers a wide potential range of sensors that may be used to determine the structural behavior of buried structures. In person-entry structures, these can be attached directly to the inner surface of the structure and monitored by direct connection. Examples include crack width gauges, strain gauges,…
ISTT
Surface-applied Lining
Surface-applied linings are considered to include linings that are sprayed, spin-cast, troweled or adhered to the interior surface of pipes, manholes, tunnels or chambers. In small pipes, such linings are possible through remote spraying or spin-casting technologies with the proper application control for…
ISTT
Surface-based Techniques
These methods are aimed at general searching for the presence of unknown buried utilities or for finding the location of known utilities for which impressed signal tracing approaches are not possible. Suitable techniques can identify the presence and approximate location and depth of buried utilities and other…
ISTT
Swaged Lining
In this category are close-fit linings in which the plastic lining pipe (typically polyethylene) is sized to fit tightly inside the existing host pipe. To allow the insertion of the lining pipe, the lining pipe is reduced in diameter just prior to installation, pulled into place and then expanded again within the host…
ISTT
System Flow Monitoring
System flow information relative to rainfall events and reports of overflows/backups provide evidence of I/I problems and their severity in a sewer system. The flow into treatment plants is monitored as a part of normal operations and gives an overall picture. Monitoring within specific basins can identify the…
ISTT
Techniques
In this category are placed the types of equipment used to carry out the inspection. These equipment types can be deployed in different ways depending on the inspection application and underground configuration (see "deployment methods").
ISTT
Thermal Environment
The thermal environment conditions that can affect trenchless utility projects can include sources of high temperature that could affect choices involving plastic pipe materials or liners. Examples could include sewers adjacent to steam lines or with condensate drains discharging to sewers and high temperature…
ISTT
Trenchless Installations
This group of methods comprise the core of what are considered “trenchless” new installation methods. In comparison with the mole ploughing or microtrenching techniques, the surface impact is not continuous and typically is limited to shaft locations or entry/exit points for the installation procedure. In…
ISTT
Troweled or Sprayed Structural Lining
Troweled or sprayed fully-structural linings are essentially coatings that have sufficient structural capacity to replace the structural function of a deteriorated pipe. This type of lining may or may not include reinforcing layer(s) to add strength and stiffness to the liner. While the linings may adhere to the host…
ISTT
Ultrasound Methods
Ultrasound methods use high frequency sound waves to penetrate a pipe wall. Reflections from the outer wall of the pipe provide time-of-travel indications of the thickness of the pipe wall. Additional information may be able to be inferred about the presence of voids outside the pipe and whether those voids are empty…
ISTT
Vacuum Extraction
The excavated material at the face may be transported to the surface using a high powered vacuum or air pressure system. Such systems have been used since the 1980s with rock and consolidated ground conditions being the most favorable for their use. As the use of vacuum microtunneling systems has spread, they have…
ISTT
Valves, Safety Equip, Appurtenances
Underground utility systems contain a wide variety of operating components and monitoring and safety systems. The operational condition of all these appurtenances must be assessed during inspections to ensure the ongoing reliability of the system. Trenchless methods can play a role in such assessments but the variety…
ISTT
Visual/Laser Inspection
While person entry viewing is possible for larger underground assets, most underground utilities require remotely operated equipment to carry out inspections. This category comprises inspection equipment that operates with visual images (e.g. CCTV inspection) or requires line-of-sight for scanning methods (e.g. laser…
ISTT
Wall Condition / Thickness
Techniques for assessing the wall condition and/or thickness from inside a pipe or manhole/chamber involve sending a wave or signal into the pipe/structure wall. Reflections, refractions and other wave disturbances potentially can provide information about the structural condition of the pipe wall, its thickness and…
ISTT
Wall Impact Methods
Wall impact methods can be as simple as hitting the wall of a tunnel with a hammer and listening for the quality of the sound to more sophisticated equipment injecting vibrational impulses into the wall and recording reflections, speed of travel, etc. One long-standing impact test for the non-destructive estimation of…
ISTT
Wireless
For deep bores, the most common tracking method uses a “wireline” to connect a tracking mechanism behind the drill head to the surface. This wireline connection presents difficulties because the connection must be maintained as new sections of drill rod are added. As an alternative to the wireline…
ISTT
Wireline
As a borehole depth increases, sonde methods eventually become ineffective (depending on the soil characteristics). For deeper bores, the most common tracking method uses a “wireline” to connect a tracking mechanism behind the drill head to the surface. This wireline connection presents difficulties…
ISTT