Evolution of the disintegration breakage of red-bed soft rock using a logistic regression model

The disintegration of red-bed soft rock is closely associated with a series of geological disasters. However, research on the evolution of the disintegration breakage has not yet been sufficiently executed. To compensate for this insufficiency, slake durability tests are carried out by three widely used experimental methods to explore the disintegration of red-bed soft rock. Then, based on the logistic regression model, the evolution model of disintegration breakage is derived, and the mathematical meaning of the model parameters (i.e., β0 and β1) is analysed. The results show that the variation in model parameters corresponds to the process of disintegration breakage. Moreover, the new formulas based on the established evolution model to calculate the disintegration index (including the slake durability index and the disintegration ratio) are presented to replace the traditional expression. Finally, the effects of the test device, drying temperature, and disintegration index on the disintegration breakage of soft rock are studied and discussed. Compared with the slake durability index, the disintegration ratio considering all mesh sizes is a more reasonable index to quantify the disintegration characteristics. The results of the present study are helpful for understanding the evolutionary process of disintegration breakage.