Shield tunnel segment surface expansion deformation measuring method and device

The invention discloses a shield tunnel segment surface expansion deformation measuring method and device, and the method comprises the steps: 1, measuring and calculating the chord length L front between two measurement mark points on a segment before the segment is assembled; 2, according to tunnel construction organization arrangement, completing splicing of the measured duct pieces till deformation of the duct pieces is stable; 3, after the deformation of the duct piece is stable, measuring and calculating the chord length L between the two measurement mark points on the duct piece again; and 4, based on the difference value between the L < front > and the L < rear >, calculating the telescopic deformation value of the measured segment before and after assembly. According to the method, the method that a large number of high-precision base points are pre-buried is omitted, construction is greatly facilitated, the construction cost is reduced, any segment of the built shield tunnel can be measured, and the