A united deformation-strength framework for Lightweight Sand-EPS Beads Soil (LSES) under cyclic loading

摘要

As a new artificial geo-material, lightweight soil is an ideal countermeasure to solve many geotechnical problems in soft ground by reducing upper load, and Lightweight Sand-EPS Beads Soil (briefly as LSES) is a typical representative. Generally used as backfill, which may bear earthquake loading or traffic loading, the behaviors of LSES under dynamic loading are worth to pay much attention on, though there are few relative studies about this at present. Based on laboratory cyclic triaxial test data presented in this study, a united framework is tried to set up, in which deformation and strength of LSES can be integrated by failure cycle number N_f that corresponds to the complete degradation of LSES structure. This framework describes both the development process of cyclic deformation and dynamic failure criteria in the state as the structure cannot afford further tension. Meanwhile, cyclic stress-strain relationships and Modulus Reduction Curves for LSES with different mixture ratios are also discussed. All distinct behaviors of LSES are considered to arise from its bond-dominated structure, which controls the two types of modulus reduction characteristics and brittle failure of LSES under cyclic loading.