Abstract
Face stability is a particularly important factor that must be considered when tunneling in loosen sand layers. If face stability can be determined, it will be an important index for tunnel planning as well as safety.
The purpose of this report is to examine face stability in view of both the dynamic and physical properties of the ground and to stady standard judgements of face stability based on investigations, tests and measuring data collected from the Kokubu River Tunnel contract which was in a loosen sand layer in which the soil condition offered insufficient face stability.
