Korean contractor, Dong-A Geological Services Co. has bought a Lovat 3.5m diameter double shield TBM that will be used to bore a 2.7km long cable tunnel under Seoul, Korea.
The US$14.4M construction contract was awarded by the client and financier, Kepco (Korea Electric Power Corp) at the end of June to general contractor SK Construction Co. The US$6.8M tunnel-only section was subsequently sub-contracted to Dong-A.
The tunnel will run uphill from a 15m diameter x 42m deep starter shaft to a reception shaft of the same dimensions. The shafts are under construction with a programmed completion in January 2002. The Lovat is scheduled for delivery in early 2002 and will go to face in March the same year.
The machine will initially bore approximately 300m before entering a 60m radius curve, followed by a 400m straight drive before a final 100m radius curve sets the tunnel onto a relatively straight alignment to its completion.
Construction will be at depths of 40-45m through rocks with varying degrees of weathering and unconfined compressive strengths ranging 25-100MPa. The TBM will erect a tunnel lining of precast concrete segments leaving the tunnel with an i.d. of 2.8m. The TBM has been estimated to breakthrough in 16 months for the start of boring with the complete contract finishing some 6 months later.
