Fiber grating vertical strain sensor

The invention particularly discloses a fiber grating vertical strain sensor, which comprises a fixed base, a hollow supporting column, optical fibers and a sensitive grating, wherein the fixed base comprises an upper base and a lower base, the hollow supporting column is arranged between the upper base and the lower base, the sensitive grating is arranged on the optical fibers and is bonded on the inner wall of the hollow supporting column, the optical fibers enter from the side surface of the upper base, run through the hollow supporting column and go out from the side surface of the lower base, temperature compensation gratings are arranged on the optical fibers which penetrate through the upper base and the lower base, and the two ends of the optical fibers are connected with fiber grating demodulators. The fiber grating vertical strain sensor has the advantages that the similarity between the material of the sensor and the material of an environment is realized through the hollow supporting column, the change of material strain distribution of the base due to embedment of the sensor is effectively avoided, and the measurement of vertical strain of roadbed materials under the effect of external acting force is realized.