A tight radius TBM is to be used on challenging tunnel alignment for Bangkok’s Metropolitan Electricity Authority.
TBM manufacturer Terratec has celebrated the successful Factory Acceptance Test of a new 4.27m diameter earth pressure balance tunnel boring machine (EPBM) destined for the Chidlom Cable Tunnel Project in Bangkok, Thailand.
The 1.35km cable tunnelling project will run through downtown Bangkok and will navigate tight alignment constraints including the foundations of the Chit Lom BTS Skytrain Station. Geological conditions consist of stiff to very stiff clay with lenses of sand and a groundwater head of about 2 bars.
According to Terratec, the EPBM has been designed with an extreme X-type articulation system, which can accommodate very tight radius curves.
The TBM’s soft ground cutterhead features an open spoke design with additional knife bits to help break-in and break-out of the concrete shaft eyes. Universal tapered precast concrete segments will typically be installed as the machine progresses, with shorter steel segments utilised during the course of the sharp radius curves.
The machine will be now shipped to Thailand and is expected to arrive in early May to be transported to the project site.