Abstract: The red clay is widely distributed in Guilin City and its adjacent areas. With the influence of human activities, geological structure and climate, geological hazards related to the red clay slaking occur from time to time. The geohazards might cause significant life and property loss in this area. Considering the slaking of the red clay under the action of water, the laboratory red clay slaking test in solutions with pH values of 2, 7, and 12, respectively, were performed. Combined with the cluster analysis, the test used the time of sample disintegration and the residual volume rate as reference indicators. The systematic cluster analysis in SPSS divided the samples that disintegrate in acidic and neutral solutions into four different categories. Under both acidic and neutral solutions, the disintegration occurred often accompanied by the escape of gas bubbles. Slaking phenomenon is very similar, and the pH value is almost unchanged; the samples that disintegrated in the alkaline solution were divided into two categories, and the sample is completely disintegrated, and its pH value decrease. Throughout the cluster analysis results combined with the experimental observations and the data to summarize the slaking characteristics of various samples under different environments and provided a theoretical basis for the prevention and the control of geological hazards caused by the red clay slaking in the engineering practice.

Key words: red clay, slake, cluster analysis