Tunnel special-shaped three-lead measuring method

Relates to the technical field of tunnel measurement, in particular to a tunnel special-shaped three-wire measuring method which comprises the following steps: step 1, arranging a central main measuring line in the center of the bottom surface in a tunnel, arranging a plurality of main measuring points at intervals along the central main measuring line, and respectively arranging two auxiliary measuring points on two side walls of the tunnel on the same section as the main measuring points; 2, embedding and fixing a prism bar at the auxiliary measuring point, and detachably erecting a forced centering device at the main measuring point; 3, installing a total station at the main measuring point of one section, installing main measuring prisms at the front and rear main measuring points of the main measuring point, installing side measuring prisms at four auxiliary measuring points of the front and rear sections of the section, and sequentially observing angles and distances from the total station to six measur