城市新鲜垃圾抗剪强度参数模型研究

 为研究垃圾填埋场堆填过程中垃圾抗剪强度参数的变化规律，考虑垃圾的压缩过程及剪切位移渐变过程，采用大型固废压缩与直剪联合测定试验仪器，对288个城市新鲜垃圾试样进行了系统地室内试验研究。试验材料分为3种配比，每种配比考虑3个初始孔隙比。试验压缩过程采用4级竖向压力，每级压力考虑8个压缩时间；剪切过程考虑10个剪应变限值。试验结果表明：抗剪强度参数c值和φ值随着剪应变限值的增加而增加，其关系可以拟合为对数表达式；在对试验数据分析的基础上，建立了一个既简单又实用的对数模型，讨论了模型拟合系数的变化规律，得到了模型拟合系数与压缩时间的关系表达式，并给出了模型拟合系数的取值范围。该模型可以预测新近填埋垃圾的抗剪强度参数，为垃圾填埋场的稳定性分析提供理论依据。

STUDY ON THE MODEL OF SHEAR STRENGTH PARAMETERS OF FRESH MUNICIPAL SOLID WASTE

To investigate the change regulation of waste?s shear strength parameters during the process of fill，the compression process and gradual change of shear displacement of the fresh municipal solid waste were taken into consideration，a large-scale combined test apparatus of compression and direct shear of municipal solid waste was used，and 288 fresh municipal solid waste testing samples were prepared in the laboratory. Three mixture proportions of the sample were adopted，and three initial void ratios were selected for each mixture proportion. Besides， four different vertical pressures were chosen for every initial void ratio，eight different compression times for each vertical pressure were selected，and ten different shear strain limiting values for each sample were considered. The testing results show that the cohesion force and the internal friction angle increase with the increasing of the shear strain limiting values，and a simple and practical logarithmic model is used to describe the relationship. Besides，the coefficients of the logarithmic model are discussed. Furthermore，the relationship between the coefficients of the model and the compression time is formulated，and the range of the fitted coefficients values is also given. The model can be used to predict the shear strength parameters of a new filled landfill，and provide a theoretical basis for the stability analysis of municipal solid waste landfills.