The Decision Aids for Tunneling (DAT) is a computer based tool with which one can obtain distributions of the tunnel constructin cost and time considering uncertainties of the geology and construction process for a given tunnel. As construction progresses, geologic information is checked based on the excavated part of the tunnel and, therefore, the uncertainty about this part of the tunnel will disappears. This new information can be used to update the geology of the tunnel in order to obtain more precise prediction during construction. In this paper, the new study on the application of the DAT to update the geology of the given tunnel is introduced. DAT simulation is updated based on face-mapping data and two approaches are used for the geologic updating of the given tunnel. The results of simulations for the initial prediction and the updated prediction will be compared in order to see how the construction time and cost distributions of the given tunnel are changed after the geologic updating.