Abstract:

Silty soils as research objects come from seasonal frost zone in Northeast China. First, experiments of frost heave under different conditions are tested in laboratory to get index of each sample which can show the degree of frost heave, namely, the ratio of frost heave. Microstructure parameters of each sample are selected and quantitative analysed by WD-5 SEM before tests. As the relationship between microstructure parameters and ratio of frost heave are nonlinear, complex, indiscernibility, a grey relation analysis and rough set theory are selected to evaluate influences of each parameter on frost heave. Results from grey relation analysis get some parameters of pore and unit which have farreaching impact on frost heave. They are of pore parameter, that is shape distribution fractal dimension, mean abundance ratio, mean circularity, mean anisotropy. And the unit parameter are mean anisotropy, shape distribution fractal dimension, and description probability entropy. The results from the method of rough set also get some parameters of pore and unit which have far-reaching impact on frost heave. The opore parameters are mean anisotropy, mean abundance ratio ,direction fractal dimension, shape distribution fractal dimension, and unit parameters are shape distribution fractal dimension, mean anisotropy, mean shape coefficient, respectively. Comparing and analyzing these results from different method, two results are considered synthetically, eight parameters influence frost heave obviously, they are four pore parameters of shape distribution fractal dimension, mean abundance ratio, mean anisotropy, direction fractal dimension and four unit parameters of mean anisotropy, shape distribution fractional dimension, mean shape coefficient, description probability entropy.

Key words: microsturcture, frost heave, grey reliability analysis, rough set theory