Abstract: Due to the reinforcement of prefabricated corrugated steel lining, the clearance area of the tunnel crosssection reduces and varies. In order to accurately clarify the specific information of tunnel clearance variation after reinforcement, 3D laser scanning technology is proposed to scan the tunnel sections before and after corrugated steel lining, meanwhile, a standardized workflow including field scanning and inner processing is established. The results indicate that: (1) There are some deviations between the profile of the actual tunnel and the design one, therefore the design data could not be used directly to process the corrugated steel. (2) The processed results of 3D laser point cloud cannot only be used to guide the segment refinement of corrugated steel, but also obtain the accurate variation of tunnel clearance before and after reinforcement by nested analysis. (3) The profile of the tunnel crosssection can still meet the limit requirement of tunnel construction after corrugated steel lining reinforcement with the maximum value of 20.3 cm at tunnel crown.

Key words: 3D laser scanning technology, corrugated steel lining, tunnel clearance variation