LTM is an innovative tunneling method, in which blasting for enlargement of the pilot tunnel as well as construction of the concrete lining can be carried out simultaneously during the excavation of the pilot tunnel by TBM. Tunnel construction can be completed in the shortest period, whereas in conventional method, the blasting for enlargement is possible only after the pilot tunnel is passed through. Therefore, the period and the cost can be reduced considerably.
In the LTM, besides the main muck car which can load a large amount of mucks, mobile ramp is used to connect the upper and lower half section of tunnel. Accidents due to the derailment can be prevented by using wide gauge (1,435mm) of rail system which is applied in normal rail road for traffic train. Same system of the muck car and the rail is used for TBM excavation and enlargement of pilot tunnel. Thereby, construction of tunnel can be carried out efficiently.