Application Of Real-time Digital Holograph In The Measurement Of Rock Stress Field

Research on the process of deformation and failure of rock is an important foundation for the analysis of rockmass stability. Under the different conditions, the rock will be have different compression strain. Over the years, on the studies of the rock damage, With the people's cognitive ability and cross-disciplinary different levels of development have also shown a different trend in the rock mechanics of the different stages of development. Generalization, it is mainly along the mathematics and mechanics analysis and experim--ental measurement of two main paths to development. Some experimental mechanics approach has been effectively applied to rock deformation, micro-experimental and rock broken trend.Based on the principle of laser digital real-time holographic interferometry, an experimental system is established. It consists of three parts, i. e. the optical layout for real-time holographic interferometry, the loading apparatus for pressure loading of the rock specimen and CCD or CMOS with a computer for graph process. In the experiment, which conducted pressure, change temperature and pre-drilling the deformation of the rock specimen during the loading process are synchronously measured under the different conditions of the real-time. Through the experiment, the real-time holographic interference frings and stress-strain curves of the rock destruction has been continuous dynamic collected. We use MATLAB computer language programming to deal with interference fringe pattern to handle and restore the video file for strain of the rock. At the same time we also summed up the rock stress-strain curves, achieved under different conditions of rock deformation process of high-precision, the audience, non-destructive, real-time, continuous dynamic measurement and visual reproduction.The main work of this paper is as follows:(1) Using digital real-time holographic method to measure the process, without prejudice to the case of real-time, while eliminating the need for the traditional real-time holographic necessary chemical treatment process. Thus simplifying the testing process and the optical path, to reduce the environmental requirements and facilitate digital image processing. At the finally of this paper use the experimental results prove the correctness of digital real-time holographic method and feasibility.(2) During the test data-processing process, we analyze the video file and gain the process of change the compression in the longitudinal get the strain of interference fringes. We use median filter and the least square method to gain the phase diagram of the object.(3) A real-time digital holographic interferometry measurement of three-dimensional objects in the calculation of small deformation is supported in this paper, which provides a feasible means for quantitative analysis of test date.