Attempt to reproduce the mechanical behavior of cement-treated soil using elasto-plastic model considering soil skeleton structure

Abstract

The improvement of sand and clay using lime or cement to control solidification is common practice. Among the many constitutive models for solidification proposed for clay and sand, few can reproduce the combined behavior of cement-treated clay and cement-treated sand. Here, four typical experimental results for cement-treated soil have been chosen from the literature to consider the shear and consolidation behavior for clay and sand, especially for a low cement mixing ratio. The elasto-plastic constitutive model was used to simulate this behavior considering the soil skeleton structure.The simulation results obtained using the model agreed with the experimental test results both for the cement-treated clay and the cement-treated sand. In the case of the clays, the experimental results were reproduceable using material constants for elasto-plastic and evolution parameters and only required changes in the initial state values, regardless of whether the soil was treated or untreated. In the case of the sands, the structure decay index of the treated sand became smaller than that of the untreated sand. Moreover, the cement-treated loose sand did not exhibit softening behavior. This was attributed to the slow rate of decay of the highly structured cement-treated loose sand due to the solidification of the cement. The degree of structure and the overconsolidation ratio both increased with higher amounts of admixed cement. The model developed in this study was capable of describing the mechanical behavior of both cement-treated clay and cement-treated sand.