Mechanical excavation method that escabates
a rock not by previous explosives blasting method but by crushing
or cutting a rock for the rock tunnel, utilized surrounding rock
as a sub-timer. It is mechanically stable round strcuture. Therefore,
the construction time is short because of largely reduced timbering
materials such as SHOTCRETE or ROCK BOLT and especially, in terms
of the construction cost and period for longitudinal tunnel it is
fairly superior method than previous one.