Improved grey correlation theory to quantitatively characterize the effect of pore parameters on compressive strength of cement Pisha sandstone

In order to objectively characterize the correlation degree of the influence of different pore parameters of cement solidified soft rock on compressive strength. The initial data of pore parameters and compressive strength are normalized by five different dimensionless methods, and the correlation degree of each parameter is calculated. Based on the mode theory and spearman theory, an improved grey correlation calculation model is established to evaluate the correlation degree of pore parameters. The results show that the correlation degree between pore parameters and compressive strength of cement Pisha sandstone is in the following order: >0~0.1μm aperture ratio, bound fluid index, >1μm aperture ratio, free fluid index, T2 spectrum area, porosity and >0.1~1μm aperture ratio. The spearman rank correlation coefficients of sample C4 were 0.964, 0.536, 0.893 and 0.964 respectively; The spearman rank correlation coefficients of sample C7 were 0.964, 0.607, 0.964 and 0.893 respectively. It can be seen that “ Range Analysis “ is the best normalization method among the five dimensionless methods, and its evaluation results are most in line with the actual situation. This study provides a new mathematical method for quantitatively characterizing the grey correlation effect of pore parameters of cement-based materials on compressive strength.