INFRARED MEASUREMENT SYSTEM FOR ROCK DEFORMATION EXPERIMENT

The infrared signals produced during rock deformation are very faint and tiny, so that the mea￣surements of them require excellent capabilities of detection system and strict working environment. The reliability of the results of infrared experiment, therefore, depends greatly on the reasonable technical specifications of infrared photodetector, high sensitivity recorder for temperature field and effectively controlled thermal background. All of the key parameters are discussed in detail in this paper based on laboratory infrared observation. The features for an infrared camera include spectral band, digitizing resolution, view field etc. For capturing the optimal infrared images, it is suggested that the spectral range should be 7～13μm, the observation range should be from 0.5m to infinity, and high density focal plane array should be employed as far as possible. In order to confirm the temperature from infrared image, a surface temperature recorder with multi thermometers should be employed as an eyewitness working alongside the camera. A realistic experiment system has been developed based on the afore mentioned discussion. Aside from the traditional functions of infrared camera, the system is fitted with high speed data transmission component. The infrared focal plane array has 320×240 pixels, and 25 frames of temperature field data are saved into the hard disk per second. Some steel beam bending and steel cylinder compressing experiments were made for testing the system. The tests have proved that the system is reliable and the data quality is improved greatly.