A porosity calculation method based on CT images and its application

Porosity analysis based on CT images is a significant method to evaluate the geotechnical porous media, and the porosity is currently calculated by threshold segmentation method for single CT image. However, because of the uncertainty of segmentation method in determining the gray threshold value for pores and matrix, even for the same CT image the calculation results from different segmentation are quite different. To overcome the drawback of gray threshold methods, a new method, called here the gray level method was proposed firstly. Using this method, CT number of images can be divided into two camps, one belongs to the pores, and the other belongs to matrix. Then, the proposed method is used to the porosity calculation of rock-soil aggregate. The estimated porosity result was compared with two segmentation methods. A close agreement with the conventional method was found and reliability of the proposed method has been proved. At last, based on the estimated porosity using the proposed method, the deformation and failure process of rock-soil aggregate is analyzed from aspect of meso-porosity evolution. ©, 2015, China Water Power Press. All right reserved.