:通过室内蠕变试验,研究了城市固体垃圾(MSW)的蠕变变形规律。采用分级加载方式对初始孔隙比为2~4和初始有机物含量在15%~75%的MSW试样进行压缩降解试验。研究发现,应力一应变一时间曲线斜率随着初始孔隙比和初始有机物含量的增加逐渐减小,即材料压缩模量逐渐减小。采用指数模型拟合城市固体垃圾的应力.应变等时曲线,并取得了很好的拟合效果,模型参数简单易求,可反映城市固体垃圾压缩性的大小及其压缩机制。通过对指数模型求导,得到城市固体垃圾的切线压缩模量,切线压缩模量随初始孔隙比和易降解有机物含量的增加呈指数型衰减,初始孔隙比在2~3之间时,初始压缩模量衰减较快,也就是说,在该范围内,初始孔隙比对城市固体垃圾变形影响较大。
Creep deformation regularity of municipal solid waste(MSW) is researched by indoor creep tests. Taking 2 series of sampels of MSW with initial void ratios from 2 to 4 and organic matter content from 15% to 75% respectively, compression- degradation tests are carried out. The findings indicate that slope of stress-strain-time curve decreases with the increasing of initial void ratio and organic matter content; and the material compression modulus decreases gradually. An exponential model is proposed to fit the stress-strain-time curve and obtaining good fitting effect. Parameters of this model are easy to get and can reflect the compressibility and its mechanism. The tangent compression modulus of MSW is obtained by the exponential model derivation and it shows exponential attenuation with the increasing of initial void ratio and organic matter content. The initial compression modulus attenuates rapidly when the initial void ratios are 2-3. That is to say, the influence of initial void ratio on deformation of MSW is larger.