RATE EFFECTS ON THE STRESS-STRAIN BEHAVIOUR OF EPS GEOFOAM

概要

論文の詳細を見る
The rate-dependency of the stress-strain behavior of EPS (Expanded Polystyrene) geofoam with densities of 19.3 and 28.0kg/m^3 was investigated by performing unconventional unconfined compression tests. A set of monotonic loading (ML) tests were performed at different constant values of vertical (axial) strain rate, ε_v. The ε_v value was stepwise changed many times and several sustained loading (SL) tests were performed during otherwise ML at a constant ε_v in other tests. A number of SL tests were performed during global unload and reload cycles to infer the stress-strain relation when ε_v=0. The elastic properties were evaluated by applying minute unload/reload cycles during otherwise ML. The rate-dependent stress-strain behaviour observed in these tests was described by an elasto-viscoplastic model (i.e., a non-linear three-component model), for which the vertical (axial) stress, σ_v, consists of inviscid and viscous components, σ^f_v and, σ^v_v while ε_v consists of elastic and irreversible components, ε^e_v and ε^<ir>_v. It is shown that the viscous property of EPS geofoam is of Isotach type in that, under the loading conditions where ε^<ir>_v is always positive, the current σ^v_v value is a unique function of instantaneous ε^<ir>_v and ε^<ir>_v, therefore the strength increases with ε_v. This viscous property was quantified based on the test results and incorporated into the model. The rate-dependent stress-strain behaviour, including the creep behaviour, observed in the experiment is simulated very well by the proposed model. In particular, the fact that the creep strain becomes significant when the sustained σ_v value becomes larger than the inviscid yield vertical stress is well simulated.
社団法人地盤工学会の論文

RATE EFFECTS ON THE STRESS-STRAIN BEHAVIOUR OF EPS GEOFOAM

スポンサーリンク

概要

著者

関連論文

スポンサーリンク