Study on the Dynamic Constitutive Relationship of EPS Particles Light Weight Soil Based on Hardin–Drnevich Model

Abstract

In order to research the dynamic stress–strain relationship of EPS (expanded polystyrene) particles light weight soil, under the condition of fixed water content and fixed curing age, the dynamic deformation properties of light weight soil with different mixing ratios are researched by dynamic triaxial tests. The results show that at the same cycle number and dynamic stress, the dynamic strain of light weight soil decreases with the increasing of cement content and the decreasing of EPS particles content. The dynamic bearing capacity of EPS particles light weight soil with cement content in the range of 10–20% and EPS particles content in the range of 0.14–0.86% is 1.5–3 times that of remolded soil. It indicates that light weight soil possesses obvious dynamic bearing capacity. In addition, when the vibration frequency increases from 0.5 to 6 Hz, the bigger the loading rate is, the more uneven the distribution of the pore water pressure in the soil is, and the less deformation can occur, which means that there is a greater constraint on the development of pore water pressure and deformation. Thus at the same dynamic strain, the dynamic stress of light weight soil under bigger vibration frequency is greater. The shape of dynamic backbone curves of light weight soil conforms to hyperbola, and its nonlinear dynamic response process can be described by Hardin–Drnevich model. Different stress state tests are used to verify the applicability of Hardin–Drnevich model. It is found that the relative errors between the measured values and calculated values of backbone curves are less than 15% by analysing the test data. It shows that Hardin–Drnevich model can be used to describe the dynamic deformation characteristics of EPS particles light weight soil.