Development of Tunnel Face Marking System

We have developed face marking system (named tunnel marker) using for tunnel construction. This system is composed with laser projector, total station, tripod, controller and surveying mirror.It can intermittently project following items to the appointed place from optical located position in the tunnel. This operation is by wireless.(1) Center point of the tunnel (2) Center line of the tunnel (3) SL diameter (4) Excavation line (5) Drilling position (for smooth brushing method) This projection is stationary image and projectable distance is about 100~300m with face intensity of illumination 150~300lux.Projection accuracy is equivalent to total station accuracy in center point of the tunnel using adjustment control. Besides: As coordinates of road (X, Y, Z) is taken for control of projector, this system makes the works easy under construction (i.e. , not only indication of drilling position and excavation line also built-in steel support, control of excavation for tunnel center line of curve process etc.)