A Time-Dependent Expansion Model for Mudstone Submerged in Water

In this study, a time-dependent expansion model of mudstone based on the rheological theory is developed. The model is validated with the results of the free expansion test of mudstone under lateral limits. We have explained the physical significance of all the parameters in the model. The ultimate strain of the mudstone flooding expansion is determined by the swelling force and progressive expansion elastic modulus. The expansion model can be used to describe and predict the time-dependent expansion of the mudstone submerged under water. The time-dependent expansion model is introduced to generalize the Einstein’s three-dimensional static stable constitutive relation to a nonstable dynamic three-dimensional constitutive relation.