Abstract
It will be very important for taking measures of tunnel support in either rational or economical way to know either strength or deformability of rock mass at the tunnel face quantitatively. In the paper, the authors propose a new rock mass classification method based on observational results obtained at the tunnel face, which will enable to know appropriate amount of support measure. The study is confirmed by the database consisting of 6, 101 sections of tunnels constructed by Japan Highway Public Corporation. The paper additionally discusses the contribution of rock condition against the mechanical rock properties and ground water inflow. An application of the method to the real tunnel construction is also illustrated and the results of application become agreeable reasonably.
