Durability Assessment for Red Stratum Soft Rock Using Different Slaking Fluids and Disturbance Modes

The present study investigated the slake durability behaviors of red stratum soft rocks subjected to different fluid soaking and disturbance modes. Several series of slake durability tests, undergoing six water-induced slaking modes, were performed to probe the slaking mechanism and durability assessment. The results showed that the evolution of the water–rock interface, driven by the loss and dissolution of clay minerals, suggests the occurrence of rock slaking. The particles produced by the slaking of red stratum soft rock were self-similar in distribution, and a logical growth model proposed can accurately predict the particle distribution from a mathematical perspective. A modified slaking breakage rate formula based on the model can be used to predict the experimental data, and the average error is 2.8%. In varied slaking fluids, the cumulative incremental of surface energy of red stratum soft-rock slaking particles increased linearly with drying–wetting (DW) cycles but displayed a semilogarithmic relationship in the external disturbance mode. In static and dynamic slaking, the maximum surface energy is 0.418 and 0.357 J, respectively. Among fractal dimension, breakage rate, and surface energy, the breakage rate is an optimal parameter for characterizing the slaking state of the red stratum soft rock, with a grey relational grade of 0.758. This study extended the slaking prediction model of red stratum soft rock in DW cycles. The achievements of the current research can provide the latent devastation and slaking breakage evolutionary process of red stratum with some references in the studied area and evaluate the optimal parameters for slake durability under different external environments.