Collapsible Soil Model for the Prediction of Mechanical Characteristics of Partially Saturated Collapsible Soils

Aeolian and kaolin deposits contribute greatly to infrastructural damage during the rainy seasons because of massive collapse settlements. The prediction of wetting-induced collapse potential and compressibility behavior under partly saturated states is essential for the development of infrastructure on these deposits. In this study, a general constitutive model was developed from the suction-controlled compression and wetting-induced collapse tests. The effect of particle orientation resulting from various initial compaction conditions, drying paths, and wetting paths on the yielding behavior of soil was investigated. A new collapsible soil model (CoSM) was presented by considering the wetting-induced changes to the clay fabric associations in the collapsible soils. The proposed CoSM requires eight parameters for evaluating the mechanical behavior. These model parameters can be readily estimated from simple compression tests, which is the major advantage of the model. The derived equations were capable of predicting three crucial mechanical characteristics, namely, loading-collapse yield, compression, and collapse behavior from the basic compression data. The model shows an excellent agreement with the measured data for two kaolin soils from the present work and several collapsible soils from the literature. The generalized model is capable of predicting mechanical behavior of collapsible soils with various initial compaction states and loading stress histories.