关键词: EPS颗粒轻质混合土, 蠕变模型, 三轴不排水试验, 经验模型, 元件模型, EPS泡沫块体

Abstract:

Expanded polystyrene(EPS) composite soil is a new kind of lightweight fill material. Compared with well-known EPS geofoam, EPS composite soil will be widely used in the future. The fundamental physico-mechanical properties of EPS composite soil have been studied by many researchers. However, the creep properties of EPS composite soil have not been published in the literatures according to our best knowledge. Firstly, the triaxial undrained creep tests were conducted on EPS composite soil with various confining pressures. Secondly, three well-known empirical creep models were used to simulate the creep behavior of EPS composite soil including Singh & Mitchell model, Mesri model, and Findley model. Singh & Mithcell model and Mesri model were able to predict the long-term deformation of EPS composite soil, however, they could not describe the initial sharp rising deformation. It was observed that Findley model which was firstly used to predict the creep behavior of EPS geofoam had the best fitting results under higher deviator stress level. To some extent, the creep property of EPS composite soil was similar to that of EPS geofoam. Finally, a new creep model was proposed for EPS composite soil, in which the element models were used to describe the elastic strain and empirical models to describe the plastic strain. It was shown that whatever the stress levels were, the proposed new creep model could not only describe the initial sharp rising deformation but also predict the long-term deformation, i.e. creep deformation.

Key words: EPS composite soil, creep model, triaxial undrained test, empirical model, element model, EPS geofoam