Model test has been more and more important as an effective method in solving the complex and special engineering problems. However

comparing with the developed model test system and the well proven similar principle

the measure technology is yet lags behind and can’t fulfill the requirement of the model test. Based on the high precision and stability of the optical grating and the optical fiber

considering the special demands of the model test

an optical sensor technology based displacement/strain model measuring system is developed and the algorithm of the data receive is improved. The system consists of the optical grating displacement measuring system and the optical fiber strain measuring system. The system has the advantage of high precision and stability and measuring discontinuous deformation. Applying the system to the model test of deformation characteristic of the salt rock underground cavern in the condition of changing of the gas injection/production

the displacement convergence and strain creep laws of the cavern are obtained; the different deformation characteristics of the surrounding rock mass in the different air pressure and velocity of the gas injection/production are got. The test is helpful for determining the proper air pressure and velocity of the gas injection/ production and is important to the safe and stable operation of the salt rock underground cavern.