考虑温度效应和纤维加筋作用的垃圾土热-弹塑性本构模型  

Thermo-elastoplastic constitutive model for municipal solid waste(MSW)considering temperature effects and fiber reinforcement

作　　者：李修磊 施建勇[2] 姜兆起 李玉萍 LI Xiu-lei;SHI Jian-yong;JIANG Zhao-qi;LI Yu-ping(Key Laboratory of Geological Hazards Mitigation for Mountainous Highway and Waterway,Chongqing Jiaotong University,Chongqing 400074,China;Research Institute of Geotechnical Engineering,Hohai University,Nanjing 210024,China)

机构地区：[1]重庆交通大学山区公路水运交通地质减灾重庆市高校重点实验室,重庆400074 [2]河海大学岩土工程研究所,江苏南京210024

出　　处：《岩土工程学报》2022年第3期523-532,I0003,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金青年基金项目(41807276,41702290);国家自然科学基金重点基金项目(41530637)。

摘　　要：考虑填埋场内垃圾土成分的复杂性和有机质降解产热导致的温度升高,根据不同温度不同纤维材料含量垃圾土的三轴试验结果,表明温度和纤维材料是影响垃圾土力学特性的关键因素,由此将垃圾土看作是类土材料和纤维材料的复合体。荷载作用下垃圾土的力学特性取决于类土材料和纤维材料的共同作用,认为温度变化只影响垃圾土的体积变形,提出了考虑温度效应的塑性体应变的硬化规律和纤维材料加筋作用的演化方程。通过构建一个新的反映温度效应和纤维加筋作用的塑性势函数,并依据相关联流动性法则导出了适用于垃圾土的热-弹塑性本构模型。通过对比文献中已有垃圾土的三轴试验结果,表明模型计算值与试验结果具有较高的吻合程度,能够很好地模拟垃圾土应力-应变曲线上翘和体应变持续增加的变化特征,以及较高围压下强度较大、较高纤维含量强度较大、较高温度下强度较小的垃圾土力学特性;在体积变形预测方面,模型计算值与试验结果虽有所偏差,但还是较好地捕捉到了较高围压下体应变较小、较高纤维含量体应变有所增大、较高温度下体应变略大的变形特征。由此可见,所建垃圾土的本构模型能够较为准确地反映围压、纤维含量以及温度对垃圾土应力-应变关系特性的影响规律,有效验证了模型的合理性。Considering the composition complexity of municipal solid waste(MSW)and the temperature rise caused by degradation of organic matters,according to the triaxial test results of MSW with different fiber contents under different temperatures,it is shown that the temperatures and fiber materials are the key factors affecting the mechanical properties of MSW.Therefore,MSW can be regarded as a composite of soil-like materials and fiber materials,whose mechanical properties depend on the combined interaction of the two materials.It is assumed that the temperatures only affect the volumetric deformation of MSW,and the fiber reinforcement effects are gradually apparent during loading.Based on this,the hardening law of plastic volumetric strain considering the temperature effects and the evolution equation reflecting the reinforcement effects of fiber materials are both proposed.Through the new plastic potential function developed with reflecting the effects of the temperatures and fiber reinforcement,the thermo-elastoplastic constitutive model is derived for MSW using the associated flow rule.Compared with the test results of different MSW,those of the proposed model are in good agreement with the test data.The main features of upward curvature of stress-strain curves and continuously increasing volumetric strain with axial stain are better reproduced by the proposed model as well as other mechanical properties of MSW such as the greater strength under higher confining pressure,greater strength with higher fiber content,and lower strength at higher temperatures.Although the calculations of the proposed model have some deviation from the test results in terms of volume change behaviors,the main volume deformation characteristics of MSW are well captured by the proposed model,including the smaller volumetric strain under higher confining pressure,lager volumetric strain with higher fiber content,and slightly larger volumetric strain at higher temperature.In conclusion,the proposed model can accurately reflect the influences

关 键 词：城市生活垃圾土 温度效应 纤维加筋作用 本构模型 应力-应变关系 

分 类 号：TU452[建筑科学—岩土工程]