Abstract
Generally, assisting methods in mountain or urban tunnels constructed by NATM were adopted in order to stabilize behaviour of tunnel face or reinforce support system under tunnel construction, but there is no definite criterion of assisting methods for adoption. In this paper, we investigate evaluation of rock condition at tunnel face and adoption of assisting methods in twin tunnels constructed in Schist mountains. As a result, we understand the actual conditions of the evaluation of rock condition and adoption characteristics of assisting methods in twin tunnel.
