基于非线性强度准则的城市固废本构模型

A Constitutive Model for the Municipal Solid Waste Based on Nonlinear Strength Criterion

考虑到城市固体废弃物(MSW)抗剪强度常具有非线性的特点,建立了一个基于幂函数形式的强度准则.并据此分析了该准则转换为线性Mohr-Coulomb准则时摩擦角的变化规律.结果表明,该准则能合理反映内摩擦角随围压增大而降低的特性.基于幂函数强度准则,采用增量硬化准则建立屈服函数,并通过构建合理的塑性势函数,建立了一个非相关联流动法则的固废弹塑性本构模型.通过对固废三轴固结排水试验结果模拟表明,所建立的本构模型不仅能合理模拟应力-应变关系,亦能正确反映其体变特性.

Considering the nonlinear characteristic of the shear strength of the municipal solid waste（MSW）, a power function strength criterion was proposed. According to the proposed criterion, the friction angle corresponding to the linear Mohr-Coulomb criterion was obtained, and it was shown to decrease with the increasing of the initial confining stress. By adopting the incremental hardening rule and suitable plastic potential function, a non-associated elasto-plasticity model was built. By predicting a series of consolidated drained triaxial tests of MSW, the proposed model was shown to be able to predict the stress-strain relationships of MSW rightly and could give out reasonable volumetric strain.