New Approach to Interpret the Mechanical Behavior of Structured Soils

The compression line of structured soils is highly nonlinear in the space of void ratio against logarithmic mean or vertical effective stresses. The variation in the compressibility with loading is attributed to the structure degradation. In this paper, the degree of structure is newly defined, and a new volume change equation for structured soils is established by using the modified mean effective stress and degree of structure as variables. The influence of the structure degradation on mechanical behavior of structured soils is explained by a degree of structure dependent normal compression index. The validity of this approach is examined via incorporating the newly defined volume change equation into the Modified Cam-Clay model. Simulations were carried out on four different types of structured soils under isotropic consolidation conditions and consolidated-drained triaxial shear conditions. Comparisons of simulation results with experimental data demonstrate that the new model provides satisfactory predicting of mechanical behavior of structured soils.