城市固体废弃物应力–应变模型研究

Stress-strain model for municipal solid waste

根据我国杭州市城市固体废弃物(MSW)的组成,在室内人工配置了MSW试样,采用静三轴CD试验研究了不同组成MSW在加载–卸载–再加载条件下的变形及强度特性。在三轴试验结果的基础上,分析了MSW应力–应变关系的特点,建立了双线性应变硬化模型,得到了包括卸载模量和泊松比在内的一套完整模型参数。研究表明,MSW的应力–应变关系受MSW组成及压实程度影响较大。采用有机物与无机物含量的比值作为垃圾组成的分类指标,有机物和无机物的比值较大时采用双线性模型更加符合实际情况;比值较小时,MSW的应力–应变关系表现出与一般土体相似的规律,可用双曲线模型表示。

The strength and deformation behavior of municipal solid waste （MSW） with different composition was studied. A bilinear strain hardening model was proposed based on the results from the static triaxial tests under loading-unloading-reloading conditions. Furthermore, a complete set of model parameters including unloading modulus and Poisson＇s ratio were determined. It was shown that stress-strain relationship of MSW was significantly affected by MSW composition and its compacted density. MSW was divided into two categories based on the ratio of organic fraction to inorganic fraction, and different models were used to describe corresponding types of MSW. It was found that there were marked strain hardening characteristics in the stress-strain relationship of MSW when the majority of its composition was organic component, and a bilinear model was proved to be more reasonable to describe this type of MSW. Whereas, the stress-strain behavior of MSW was similar with that of soil when the majority of its composition was inorganic, and the hyperbola model could be used to describe the stress-strain relationship of this type of MSW.