摘要
螯合飞灰是生活垃圾焚烧飞灰经螯合剂稳定化处理后的产物,研究螯合飞灰的力学特性对其填埋设计和路基填筑应用至关重要。通过无侧限抗压强度试验和三轴剪切试验,研究含水率、干密度对螯合飞灰力学特性的影响,建立应力-应变本构模型及模型参数与含水率、干密度的关系,最后利用扫描电镜分析微观机理,提出螯合飞灰路基填料的施工含水率和干密度。结果表明:螯合飞灰的最大无侧限抗压强度为363.35 kPa,有效黏聚力和有效内摩擦角范围分别为14.22~56.58 kPa和28.69°~31.44°;强度、有效抗剪强度指标分别随含水率和干密度的增加而近似线性下降和上升,同时无侧限抗压强度与抗剪强度呈幂函数关系;三轴和无侧限应力-应变关系可分别用沈珠江及修正过镇海本构关系模型表征,计算值与实测值的相对误差均在7%以内;螯合飞灰颗粒间的胶结作用随含水率降低而增强,松散粉状颗粒随干密度增加逐渐变为块状结构,从而提高试样的力学性能;为确保螯合飞灰具备良好的力学性能和路基稳定性,建议其用作路基填料的施工含水率为25%~29%,干密度大于1.193 g·cm^(-3)。研究结果可为确定螯合飞灰的力学参数提供参考,对其填埋处置和路基填筑应用具有重要的工程意义。
Chelated fly ash is the product derived from municipal solid waste incineration fly ash stabilized by chelating agent.It is crucial to investigate the mechanical properties of chelated fly ash for landfill design and subgrade construction applications.Through unconfined compressive strength tests and triaxial shear tests,the influence of moisture content and dry density on the mechanical properties of chelated fly ash was studied.Additionally,stress-strain constitutive models and the relationships between model parameters,moisture content,and dry density were established.Finally,the microscopic mechanisms were analyzed by scanning electron microscopy,and the optimal construction moisture content and dry density of chelated fly ash subgrade fillers were proposed.The results showed that the maximum unconfined compressive strength of chelated fly ash is 363.35 kPa,and the ranges of effective cohesion and effective internal friction angle are 14.22~56.58 kPa and 28.69~31.44°,respectively.Strength and effective shear strength parameters decrease approximately linearly with increasing moisture content and increase with increasing dry density.The triaxial and unconfined stressstrain relationships could be characterized using the Shen Zhujiang and modified Guo Zhenhai constitutive models,respectively,with relative errors between calculated and measured values within 7%.The cementation effect between chelated fly ash particles was enhanced with decreasing moisture content,and loose powdery particles gradually transform into blocky structures with increasing dry density,thereby enhancing the mechanical properties of the samples.To ensure good mechanical performance and subgrade stability,the recommended construction moisture content for chelated fly ash as subgrade filler was 25%~29%,with a dry density greater than 1.193 g·cm^(-3).The research results provide references for determining the mechanical parameters of chelated fly ash,offering significant engineering insights for its landfill disposal and subgrade filling applications.
作者
陈爱军
李超华
张东波
蔡建军
吴迪
CHEN Aijun;Li Chaohua;ZHANG Dongbo;CAI Jianjun;WU Di(School of Architecture and Transportation Engineering,Guilin University of Electronic Technology,Guilin 541004,China;Guangxi Communications Design Group Co.,Ltd.,Nanning 530029,China)
出处
《环境工程学报》
北大核心
2025年第4期965-977,共13页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金地区项目(42067044)
广西自然科学基金面上项目(2022GXNSFAA035485)。
关键词
城市垃圾焚烧飞灰
抗剪强度指标
抗压强度
应力-应变关系
微观结构
municipal solid waste incineration fly ash
shear strength parameter
compressive strength
stress-strain relationship
microstructure
