Abstract
Various auxiliary methods have been carried out in tunneling sites due to increasing in the size of the tunneling machines and developing their technology. Thus, full-face tunnel excavation has been increasingly employed for sequential excavated method tunneling as well as the ground control effect of early ring closure. As the stability of the tunnel face is essential to full-face tunnel excavation, the tunnel stabilizing method utilizing curved tunnel faces, which would naturally form as part of the tunnel excavation sequences, can be considered effectively.
This paper addresses an investigation into the stability of various shapes of tunnel face considering full-face and bench cut methods. In order to clarify the stability, we carried out the model tests using base friction apparatus and numerical simulations with discrete element method (DEM). As a result, it was confirmed that curved tunnel faces were advantageous and the stability of the tunnel face could be improved by a simple reinforcing method such as shotcrete on tunnel face. In addition, we concluded that there was a difference in the reinforcing effect by the shape of the tunnel face or excavation method.
