Immersed tube tunnel steel shell boundary dimension measuring method

The invention discloses an immersed tube tunnel steel shell boundary dimension measurement method, and relates to the technical field of immersed tube tunnel steel shell parameter measurement. The measurement method comprises the following steps: setting measurement points on a to-be-measured immersed tube tunnel steel shell, wherein the measurement points comprise a first length measurement point, a second length measurement point, a first width measurement point, a second width measurement point, a first height measurement point and a second height measurement point; establishing a three-dimensional coordinate system, wherein a first axis, a second axis and a third axis of the three-dimensional coordinate system are respectively parallel to the length direction, the width direction and the height direction of the immersed tube tunnel steel shell to be measured; measuring and obtaining three-dimensional coordinates of the measuring points through a three-dimensional coordinate measuring device; and calculati