Scanning technic is implemented with the underground structures: subway, tunnel, shaft, drainage path, spillway, and slurry wall. Both optical and laser scanning system have been conducted to the precise inspection of diagnosis and safety. Image and 3D coordinate from scanning can be utilized in monitoring scope and fundamental database of maintenance. There is a high possibility that the scanning will prevail on inspection and diagnosis.

In light of the maintenance of underground structures, the evaluation scope of precise inspection for safety and diagnosis have been revised. Crack, leakage, deterioration, and drainage system are evaluated with field inspection in maintenance manner. It also proposed that the additional revision of the precise inspection for safety and diagnosis.