Abstract: The crack propagation patterns in different uniform samples and crack development in samples with different degrees of compaction are studied on the expansive soil samples in Nanyang. The prepared saturated samples simulating the different working conditions were first weighted and then placed in a constant temperature oven. The surface images of the sample were digitally recorded. The number, width, and length of the cracks expansive soils were processed and analyzed with MATLAB. The processed data are logged into the EXCEL spreadsheets and then are presented in line charts. The line chart can presents the quantitative features of the cracks and their developments.

Key words: Surface Cracks, Digital Photograph, MATLAB, Evolution Rules