不同压力下垃圾降解压缩试验研究

利用课题组设计研制的垃圾降解压缩试验仪,将新鲜垃圾试样在100,200,400 kPa三个竖向压力作用下分别进行室内降解压缩试验。试验模拟了不同降解条件下填埋场垃圾的沉降过程,对比研究了压力对垃圾土长期沉降的影响。试验结果表明,当垃圾处于适宜的降解环境时,垃圾中有机物的生物降解导致沉降速率逐渐增大,产生比较显著的降解沉降。试样所受的压力越大,产生的主压缩应变越大,后期的降解沉降和蠕变沉降越小。随着时间的增加,压力对总沉降的影响相对减小。压缩参数与垃圾的降解状态有关,应变与时间对数曲线中在压缩前期和后期近似呈线性关系,压缩前期修正次压缩指数较小,后期垃圾加速降解时修正次压缩指数较大。

Biodegradation-compression tests on municipal solid waste subjected to different vertical pressures

In order to investigate the long-term deformation properties of municipal solid waste (MSW) subjected to different vertical pressures, three biodegradation-compression test apparatuses for MSW are developed, whose functions include loading, temperature controlling, leachate recirculating, and gas collecting. Artificial waste samples filled in the test apparatuses are compressed under different conditions in the laboratory to simulate the settlement of MSW in landfills. The test results show that the primary settlement increases and the long-term settlement decreases respectively as the vertical pressure acting on the samples increases, and that the effect of pressure on the total settlement exhibits a decreasing trend with the increasing time. When the refuse is under appropriate decomposition condition, the settlement rate increases due to the enhancement of refuse decomposition, which results in significant settlement. Compressibility parameters are correlated with the state of decomposition. The strain-logarithmic time curves for the samples are approximately linear with a relatively flat slope at the early stage of compression, and at the last stage of compression, the strain-logarithmic time curves are also linear, but the logarithmic compression rate becomes large because of the added effects of decomposition.