考虑剪缩性的城市固体废弃物非线性弹性模型

Nonlinear elastic model for municipal solid waste considering dilatancy effect

针对城市固体废弃物(MSW)具有明显剪缩特性的特点,提出能够考虑剪缩性的非线性弹性模型.通过三轴固结不排水(CU)试验验证MSW的剪缩性,在传统非线性弹性模型框架中引入了剪缩模量与压硬模量,将固废的体积应变分解为由平均正应力与切应力产生的2个部分,基于三轴固结排水(CD)试验提出体积应变和广义切应变的全量表达式,通过微分手段获得剪缩模量和压硬模量的具体表达式.采用多学者的MSW试验结果对模型进行验证.结果表明,模型的拟合效果较好,各参数的离散型较小,能够较清楚地描述垃圾的力学特性.

A nonlinear elastic constitutive model considering the dilatancy behavior was proposed in order to describe the obvious dilatancy behavior of municipal solid waste（MSW）.The dilatancy behavior of MSW was approved based on consolidated undrained triaxial compression tests.Dilatancy modulus and hardening modulus were introduced in traditional nonlinear elastic constitutive models.The volumetric strain of MSW was divided into two parts：generated by mean normal stress and by shear stress.Total expressions of normalized volumetric strain and generalized shear strain were established based on consolidated drained triaxial compression tests,and the dilatancy modulus and hardening modulus of the proposed model were obtained by differential.The proposed model was used to simulate test results obtained from published studies.The values of model parameters are different with different MSW samples or test conditions but fall within a relatively limited range.The simulation results accorded with the experimental values in general.