Tunnelling Technology
The tunnels of the KVMRT project are built using high-precision mechanised tunnelling machines commonly referred in the industry as Tunnel Boring Machines (TBMs). These machines are like moving underground factories that mine through rock and soil while simultaneously installing a permanent pre-cast concrete lining that forms the tunnel rings.
Variable Density (VD) TBM
Winner of 2014’s Technical Innovation of the Year Award from the International Tunnelling and Underground Space Association, the VD TBM is a home-grown solution designed to operate in multiple tunnelling modes, with the added ability to vary its slurry density to tackle different ground conditions.
The development of the ‘variable density’ enhancement stemmed from MMC Gamuda’s previous experiences tunnelling through similar karstic limestone conditions during the Stormwater Management and Road Tunnel (SMART) project, which encountered numerous sinkholes and settlements with significant impact and damage to public roads and properties.
Accordingly, the introduction and use of the VD TBM during the construction of the MRT Kajang Line resulted in a 95% reduction in sinkhole occurrence incidents compared to the SMART project, echoing the resounding effectiveness of the VD TBM in the level of achievable ground control.
The first of its kind in the industry, the VD TBM is still continuously being optimised and increasingly automated to push the boundaries of better underground construction, leading to the debut of the autonomous VD TBM in the MRT SSP Line project. Created by a team of Malaysian engineers and tested in real urban environments, the system has shown promising results in the following auto modes:
- Auto-steer
- Auto-excavate
- Auto-advance
- Auto-slurry
The first of its kind in the industry, the VD TBM is still continuously being optimised and increasingly automated to push the boundaries of better underground construction, leading to the debut of the autonomous TBM (A-TBM) in the MRT Putrajaya Line project.
Created by a team of Malaysian engineers and tested in real urban environments, the A-TBM has shown promising results in various TBM sub-systems, garnering multiple global awards.
Earth Pressure Balance (EPB) TBM
The EPB TBM will be used in geology associated with Kenny Hill, a soil condition that is cohesive with low permeability. The EPB TBM supports the excavation and tunnel face with the use of polymer slurry to make form an impermeable “paste” that regulates the amount of material excavated and the TBM’s advance rate. For the MRT Putrajaya Line, four EPB TBMs will be used to tunnel through Kenny Hill formations in the underground alignment.
