【摘要】 城市生活垃圾填埋场因有机质降解产热导致其内部温度长期高于环境温度，引发工程运维问题。垃圾土温控三轴试验结果发现，温度变化引起的垃圾土体积应变与应力水平有关，且弹性体积应变占比较大，影响以塑性体积应变为硬化参数的弹塑性本构模型研究。在前期试验基础上，采用GDS温控应力路径三轴仪，研究了排水条件下温度对垃圾土中黏土体积变形特性和压缩特性的影响，并与相同条件下垃圾土体积变形特性进行比较，揭示了温度变化对垃圾土体积变形特性的影响机制。基于垃圾土温控三轴试验结果，推导了垃圾土热弹塑性压缩指数λ_T和热弹性压缩指数κ_T的确定方法；采用等效应力原则，假设温度变化引起的弹塑性体积应变等于某一等效应力增量引起的弹塑性体积应变，建立了垃圾土在热-力耦合作用下的体变计算模型，并对模型进行了验证分析。研究结果表明，孔隙比是影响垃圾土温度体积应变的主要因素；垃圾土的λ_T和κ_T随初始固结应力的增加而减小，比黏土高一个数量级；选取常温下相应固结应力水平的回弹指数κ和压缩指数λ比例值（κ/λ）能够较好地模拟热-力耦合作用下垃圾土的体积变形特性。更多还原

【Abstract】 The internal temperature of municipal solid waste(MSW) landfills is chronically higher than the ambient temperature due to heat production from organic matter degradation, which leads to engineering operation and maintenance problems. Existing experimental results show that the thermally induced volume changes of MSW were stress dependent and the elastic volumetric strain was significant, the latter may affect the determination of plastic volumetric strain which is usually used as the hardening parameter of constitutive model. On the basis of the previous tests, the effect of temperature on the volumetric deformation and compression characteristics of the clay in MSW under drained conditions were investigated by using the GDS temperature-controlled stress path triaxial apparatus, and the results were compared with the volumetric deformation characteristics of MSW under the same conditions to reveal the influencing mechanism of temperature change on the volumetric deformation characteristics of MSW. The methods of determining the thermal elastoplastic compression index λ_T and thermal elastic compression index κ_T of MSW were derived based on the results of MSW temperature-controlled triaxial tests. By adopting the principle of equivalent stress and assuming that the elastoplastic volumetric strain induced by temperature change was equal to the elastoplastic volumetric strain induced by an equivalent stress increment, a computational model for the volumetric deformation of MSW under thermo-mechanical coupling effect was established, and the model was validated and analyzed. The results showed that the void ratio was the main factor affecting the thermal volumetric strain of MSW. The λ_T and κ_T of MSW reduced with the increase of the initial consolidation stress, which were one order of magnitude larger than those of clay. The ratio of compression index λ and swelling index κ(κ/λ) at the corresponding consolidation stress level and normal temperature could be selected to simulate the volumetric deformation characteristics of MSW under thermo-mechanical coupling effects.更多还原