Abstract: A series of CT scan tests were performed on the standard coal rock samples before and after the unconfined compressive strength tests. The porosity in the coal rock samples is extracted from the CT scan images by using Hough transformation. The micro porosity structures in the standard coal rock samples are three dimensional reconstructed by adjusting the threshold values. Comparing with the conventional threedimensional reconstruction methods, the porosity extraction method has a wider application and has a better presentation of the internal damage in the standard coal rock sample. The reconstructed 3D structure is used in the numerical analysis in COMSOL model. The results indicate that, 1) the size and distribution of the porosity can be obtained from the Hough transformation; 2) The initial damage in the coal rock samples significantly reduces the strength of the coal rock samples 3) The stressstrain curves obtained from the elastoplastic threedimensional porosity reconstruction are similar to that of curves from the unconfined compressive test so that the accuracy of the porosity extraction method is therefore verified.

Key words: Hough Transformation, CT Scan, Porosity Extraction, 3D Reconstruction, Rock Damage