抄録
One of the most important items to prevent the accidents caused by the cutting face collapse, such as ground surface depression, is an estimation of the cutting face stability during NATM excavation. Observation point of the cutting face stability is it's deformation. However, excavating operations are done on the tunnel cutting face all day long, it is very difficult to install the observational equipments on theface without interruption. Therefore, we tried to predict the cutting face stability using the observation of the tunnel crown deformation instead of the cutting face deformation.
As a result, the strain velocity of the crown et was effective to estimate the cutting face stability.
