Statistical regularity of physical and mechanical indexes of secondary red clay in Chenggong District, Kunming

In order to analyze the statistical regularity of physical and mechanical indexes of secondary red clay in Chenggong District, Kunming, the index data of 275 groups of secondary red clay samples from 69 geotechnical investigation boreholes in Wujiaying area of Chenggong are taken as the research object. Based on the statistical analysis principle, the variation range, average value, standard deviation, coefficient of variation of 13 indexes and the correlation between indexes and depth are analyzed by SPSS statistical analysis software, and the physical and mechanical properties of secondary red clay are summarized. Then, the linear empirical formula between indexes is fitted, and the normal distribution regularity of indexes is tested by skewness and peak method. The results show that the secondary red clay has a large specific gravity of soil particle, low plastic limit and liquid limit, mainly in plastic state, high compressibility and low shear strength. The correlation between indexes and depth is not strong, and the discreteness of mechanical indexes is greater than that of physical indexes, while the index dispersion of secondary red clay is larger than that of primary red clay. The overall correlation between the indexes is weak, with the void ratio, compressibility and wet density, the internal friction angle and water content ratio negatively correlated, and the compression modulus, cohesion and wet density, the plasticity index and natural water content positively correlated. Only the wet density, void ratio and internal friction angle follow the normal distribution. The research results provide a reference for the geotechnical engineering design and the selection of geotechnical parameters in Chenggong District of Kunming, and offer a basis for the engineering disaster prevention and mitigation in the secondary red clay area.