考虑应力路径影响的垃圾土应力-应变特性  

Influence of stress path on stress-strain behavior of municipal solid waste

作　　者：李修磊 施建勇[2] 李玉萍 LI Xiulei;SHI Jianyong;LI Yuping(Key Laboratory of Geological Hazards Mitigation for Mountainous Highway and Waterway,Chongqing Municipal Education Commission(Chongqing Jiaotong University),Chongqing 400074,China;Geotechnical Research Institute,Hohai University,Nanjing 210098,China)

机构地区：[1]山区公路水运交通地质减灾重庆市高校重点实验室(重庆交通大学),重庆400074 [2]河海大学岩土工程科学研究所,南京210098

出　　处：《哈尔滨工业大学学报》2023年第2期134-142,共9页Journal of Harbin Institute of Technology

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

摘　　要：填埋场内垃圾土体存在多种应力状态(如压缩、拉伸、加载和卸载等),常规三轴试验和直剪试验难以全面进行模拟。为此,利用GDS三轴仪针对垃圾土重塑样开展9种不同应力路径下的三轴试验,深入研究分析应力路径对垃圾土应力-应变特性和屈服特性的影响,提出描述垃圾土应力-应变关系统一的数学模型,并得到p-q应力空间上垃圾土的屈服轨迹。通过与砂土进行比较,揭示应力路径对垃圾土中纤维材料加筋作用的影响规律。结果表明:对于σ_(3)≥0的压缩路径,垃圾土的应力关系曲线上翘,没有任何出现峰值或趋于渐近值的迹象,纤维材料起到的加筋作用最显著;对于σ_(3)<0的压缩路径,垃圾土的偏应力随轴向应变增加而增大,并逐渐趋于某定值,纤维材料起到的加筋作用较弱;对于Δ_(q)<0的伸长路径,垃圾土与砂土的应力-应变关系曲线近乎一致,纤维材料几乎不产生加筋作用。垃圾土中纤维材料的加筋作用与应力路径密切相关,研究成果为全面深入理解垃圾土的力学特性提供了依据。There are various stress states of solid waste mass in landfills(e.g.,compression,tension,loading,and unloading),which are difficult to be fully simulated by using conventional triaxial tests and direct shear tests.Triaxial tests on reconstituted municipal solid waste(MSW)specimens under nine stress paths were carried out by GDS triaxial apparatus to analyze the influence of stress path on the stress-strain behavior and yielding characteristics of MSW.A unified mathematical model was proposed to describe the stress-stain responses of MSW,and the yielding locus of MSW was obtained in p-q stress space.By comparing the stress-strain relationships of sand soil and MSW,the effects of stress path on the reinforcement of fiber materials in MSW were discussed.Results show that for compression stress path withσ_(3)≥0,the stress-strain curves of MSW exhibited an upward curvature without any peak or asymptotic values,and the reinforcing effect of fiber materials was the most significant.For compression stress path withσ_(3)<0,the deviatoric stress of MSW increased with increasing axial strain and it gradually tended to a certain value,while the fibrous reinforcement was weak.For extension stress path withΔ_(q)<0,the stress-strain relationships of MSW were almost the same as those of sand soil,and there was no fibrous reinforcing effect in MSW.In conclusion,the fibrous reinforcing effect in MSW is closely related to stress path,and the research data provides a basis for comprehensive and in-depth understanding of the mechanical properties of MSW.

关 键 词：城市生活垃圾土 应力路径 三轴试验 应力-应变 屈服特性 

分 类 号：U43[交通运输工程—道路与铁道工程]