A launching pit from a Shuttlemole construction project.
EVOLUTION OF THE SHUTTLEMOLE
by Tony A Suzuki, Iseki Poly-Tech and Todd M Kilduff, Iseki North American Representative &
Kilduff Underground Engineering
After being recognised last year with an award for one of its new machines, Iseki Poly-Tech has spent 2017 continuing the development of its Shuttlemole MTBM , culminating in its deployment on three ground- breaking projects in South East Asia.
In 2016, Japanese microtunnelling machine manufacturer Iseki Poly-Tech was honoured with an ISTT Award in the‘New Machine’ category at theInternational No-Dig Conferenceand Exhibition in Beijing, China for the development of its Shuttlemole system.
A unique microtunnel boring machine (MTBM),the Shuttlemole is equipped with a shield that can be removed without a receiving shaft. Instead, it has the unique ability to be retracted through the installed pipe back to the launching shaft, allowing it to construct a pipeline without a receiving pit
During the initial stages of its development, the machine was primarily planned to support Iseki piperoofing projects. However, it was found to have additional benefits, such as the ability to
avoid foreign obstructions along the pipe roofing pipeline, which meant the MTBM could be retracted and re-installed to its last position. Without the presence of the MTBM, the obstruction could be removed as the machine was re-deployed. The Shuttlemole is now in operation and has successfully been used to compete several jobs, including the three which are notable for their innovation.
Pipe material: 1,200 mm OD steel pipe. Number of pipes: 27 casing pipes.
Length of pipe canopy: 200 m.
The purpose of pipe roof was to provide a supplemental method for a deep subterranean tunnel construction at a highway junction. The project involved the installation of a pipe roof consisting of 27 1,200mm OD steel pipes to provide a pre-excavation support system for the tunnel prior to enlarging works at entrance and exit portion of highway.
The piperoof was critical in reducing surface settlement. The launch location was from a narrow space under a high ground water table in deep earth cover (maximum 60m deep)
Pipe material : 800mm OD steel pipe.
Number of pipes: 36
Length of pipe canopy: 30 m
The Shuttlemole was first adopted overseas for a project in Singapore in 2016. The pipe canopy was installed to facilitate the construction of a pedestrian underpass for a congested main road.
While the project originally planned to use open-cut methods, construction of the pipe roof was able to shorten the project duration and provide economic benefits. Further cost and scheduling benefits were obtained using the Shuttlemole, eliminating the need for a reception shaft.
One of the concerns prior to construction was the presence of numerous existing utilities. However, the deployment of the Shuttlemole meant it was not necessary to remove the utilities.
The MTBM encountered several obstacles during construction, some of which were existing sewerage pipes. Despite encountering these obstacles, the project was able to be completed without significant delay
The Shuttlemole’s capabilities are still being further developed and although it has been primarily used for the installation of steel pipe, there are also advantages when using it with reinforced concrete (RC) pipe. At this time it can only be used for this purpose as a prototype and can be developed at the request of the contactor following an examination of the conditions of the jobsite. It is hoped that Shuttlemole will eventually be manufactured for this specific use, as well as introducing a full range of system diameters to the market.
The Shuttlemole is an innovative new MTBN.
THE MICROTUNNEL BORING
FOUND TO HAVE ADDITIONAL
BENEFITS, SUCH AS THE
ABILITY TO AVOID FOREIGN
OBSTRUCTIONS ALONG THE
PIPE ROOFING PIPELINE,
WHICH MEANT THE MTBM
COULD BE RETRACTED AND
RE- INSTALLED TO ITS LAST
Pipe diameter: 1,650 mm ID RC pipe.
Jacking length: 299 m (including curve section:R=80m).
Jacking condition: launching from existing manhole and arrival at basement of existing station.
This drainage project in Japan utilised a 1,980 mm OD machine to travel through an existing manhole directly to the basement level of an existing subway station. Most of the jacking equipment was set up at each floor in the existing manhole, ready to be launched.
The arrival point, in the basement of the subway station, was a narrow space which did not allow for the recovery of a traditional machine. Therefore the Shuttlemole, which is recovered through the jacking pipe, was adopted for the project.
The MTBM shell and shield were split and carried into the launch area to account for the limited space. It was then reassembled on the launching guide rail and installed within the launch area, ready for excavation.
The Shuttlemole also has the capabilities to retract and re-install RC pipe. In addition, it has also been developed to contribute to various kinds of installations, including those with curved drives.
The machine has been able to demonstrate multiple benefits in addition to pipe roofing, which are useful for a variety of project types. Iseki said it hopes that the Shuttlemole will further enhance the structural integrity of installations it is utilised for.