Tunnel section average linear overexcavation detection method

The invention discloses a tunnel section average linear overexcavation detection method. The method comprises the following steps: step A, acquiring actually measured point cloud data of a tunnel section; step B, calculating the overexcavation area of the tunnel section; step C, acquiring the average linear overexcavation value of the tunnel section by the over-excavation area of the section and the arc length corresponding to the central angle of the section actual measurement point cloud contour on the design contour; before the average linear over-excavation value of the tunnel section is calculated, judging the height value Hkw of the excavation height line K1 and the height value Hqg of the height line K2 of the arch camber point at first. The average linear over-excavation value of the arch part and the side wall can be calculated respectively, due to different management and control standards of the linear over-excavation value of the side wall and the arch part, guidance can be conducted when the exca