An Automated Surveying and Marking System for Continuous Setting-out of Tunnels

AbstractSetting-out is a crucial and frequently repeated process in construction and civil engineering. It is carried out by qualified operators who, making use of surveying stations, identify reference points to guide workers in their tasks. In this paper, we focus on the particular case of setting-out road/train tunnels and propose a system that automatically performs the setting-out operation of the tunnel section to be perforated. The presented system, called Tunnel Continuous Setout TCS, integrates a scanning device that surveys the excavation front and a laser projector that continuously displays the actual tunnel section computed as the intersection between the surveyed terrain and the planned tunnel section. Thus, the topographer intervention is only required for the precise positioning of the TCS device at the beginning of each working stretch, which depends on the operational range of its components limited to 25 meters in the current implementation. A prototype of the TCS system has been employed in a real construction site proving its benefits and advantages with respect to the traditional setting-out techniques.