Abstract：Based on real-time computerized temography(CT) experiment on concrete samples with three sets of cracks under uniaxial loading，some new phenomena and laws on meso-crack and meso-damage by numerical computation for non-interpenetrated jointed media are presented；and the effect of six material parameters on the meso-damage of sample is predicted by Monte Carlo probabilistic design method. Over double decades，the experimental technology of computerized tomography has provided an efficient approach to obtain visible picture for micro or meso damage and fracture of rock and soil media，which leads to the micro or meso problems not to be guessed. However，some complicated phenomena and evolutional laws have to be explored and discussed through the numerical analysis due to the limit of equipment，method and sample of experimental situation，etc. Hence，the latest development of CT experiment results is reviewed firstly. Considering the elementary concept of the problem，the data from test and special criteria about meso-crack and meso-damage，the parameters of grey-scale are regarded as the main variable for computing simulation. In fact，the meso-crack and meso-damage could occur in the case of tension and shear based on the damage criteria for 3D elements. According to computing demand of higher precision，the main program is compiled by Fortran language using 3D isoparametric elements with 16 nodes to simulate the crack and the surrounding elements，and that with 8 nodes to simulate the elements far from the crack. Meanwhile，except for shear transfer coefficient for crack open and that for crack closure obtained by probabilistic design approach，all the other parameters are determined by the experiment. As a consequence of computation，the grey-scale distribution，meso-crack distribution，meso-damage distribution，average grey-scale curve and meso-damage isoline distribution on the middle section of the sample are presented in detail. Furthermore，meso-crack and meso-damage inherent evolution laws are come out as well. Finally，the influential parameters of meso-damage model on the middle section such as initial elastic modulus，Poisson ratio，shear transfer coefficient of crack open，shear transfer coefficient of crack closure，limit uniaxial stress of tension and initial density are predicted. The study shows that the characterization of meso-crack and meso-damage for rock or soil is of a stage-like behavior，which varies with material properties，initial situation of sample and loading style，etc. The results may be useful for the research on the evolution law of non-interpenetrated jointed media.
