城市固体废弃物动力特性试验研究
Experimental research on dynamic properties of municipal solid waste
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摘要: 参照杭州天子岭填埋场城市固体废弃物(MSW)主要成分,人工配制固体废弃物试样,利用中型动三轴试验仪研究其在较大应变范围内MSW的动力特性。MSW的动剪切模量Gd和阻尼比D随着动剪应变γd的变化曲线与泥炭土的相关曲线形状基本一致,并且在相同应变时数值相差不大。在相同的动剪应变水平下,随着围压的增大,Gd增加而D减小;当动剪应变增大时,Gd减小而D增大。由于MSW的高压缩性,初始孔隙比不同对试样的动力特性影响不大。同时进行了现场剪切波速试验,确定了最大动剪切模量Gdmax的估算式。为便于应用,建议了归一化Gd和D与动剪应变依赖关系的取值范围和平均值曲线,并将其与OII填埋场MSW动力特性的研究结果进行对比,可以看出MSW的成分对其动力特性的影响还是比较大。Abstract: To investigate the dynamic properties of municipal solid waste (MSW) in the range of large strain, dynamic triaxial tests were conducted using moderate-scale triaxial apparatus on MSW samples simulating the compositions of MSW from Hangzhou Tianziling Landfill. It is concluded that the relationships of dynamic shear modulus and damping ratio versus dynamic shear strain of MSW are similar to those of peaty soil. The dynamic shear modulus increases and damping ratio decreases as the confining pressure increases under the same dynamic shear strain level, but the dynamic shear modulus decreases and damping ratio increases as the dynamic shear strain increases under the same confining pressure. Because of the high compressible property of MSW, the influence of initial void ratio is very little. At the same time, a formula for evaluating the maximum dynamic shear modulus is proposed on the basis of experimental results of shear wave velocity. The ranges of variation and average curves of the normalized dynamic shear modulus and damping ratio versus dynamic shear strain are proposed, which are compared with those of OII landfill. It is found that the composition of MSW affects significantly its dynamic properties.