Shuttlemole:Its Origin and Evolution
A launching pit from a Shuttlemole construction project.
Shuttlemole is a unique microtunnel boring machine (MTBM) with which no arrival shaft is needed to be retracted. It is equipped with a shield, which makes it possible to retract the machine through the installed pipe at a drive shaft.
Shuttlemole was originally planned to support our pipe-roofing projects. However, it was not long before we found its additional benefits. One of them is the ability to avoid foreign obstructions along the pipe-roofing pipeline, as the MTBM could be retracted and reinstalled to its previous position after the obstruction was removed. Shuttlemole is also beneficial in cases where construction space is limited (e.g., modern urban areas).
Shuttlemole has been used to complete several jobs and it has won an ISTT Award in the ‘New Machine’ category at the International No-Dig Conference in 2016. Here are notable projects for its evolution.
Pipe material: 1200mm OD steel pipe. Number of pipes: 27casing pipes.
Length of pipe canopy: 200m.
The purpose of pipe-roofing method was to provide a supplemental reinforcement for a deep subterranean tunnel construction at a highway junction. The project involved the installation of a pipe roof consisting of 27 1200mm OD steel pipes.
The pipe roof 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: 27casing pipes.
Length of pipe canopy:30m
Shuttlemole was first used 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.
Pipe-roofing method with Shuttlemole shortened the project duration and provided economic benefits, without the need for an arrival shaft.
One of the concerns prior to construction was the presence of numerous existing utilities. However, the deployment of 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 is an innovative new MTBM.
THE MICROTUNNEL BORING MACHINE(MTBM) 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.
Pipe diameter: 1650mm ID RC pipe.
Jacking length: 299m (including curve section:R=80m).
Jacking condition: launching from existing manhole and arrival at basement of existing station.
This drainage project in Japan utilized a 1980mm OD MTBM 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.
The arrival point, in the basement of the subway station, was too narrow to retract a conventional MTBM from.
Therefore Shuttlemole, which is retractable through the jacking pipe, was adopted for the project.
The MTBM shell and shield were split and carried into the launch area before they were reassembled on the launching guide rail and installed within the launch area.
Shuttlemole also has the capabilities to retract and re-install RC pipe. In addition, it has been developed to contribute to different 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. Shuttlemole will further enhance the structural integrity of installations it is utilized for.