Experimental Study On The Dynamic Behavior Of Municipal Solid Waste

Along with economical development, our country's urbanized advancement is getting quicker and quicker, the urban population is getting more and more, the production quantity of municipal solid waste(MSW) was also increased year by year, the disposal of MSW has become more and more concerned. Sanitary landfill method,a widely used urban waste disposal technology,is one of the most ecomonic and effective methods. The scale of landfill gradually grows, MSW reserves increased year by year, it also influnced the security of the landfill, especially in the case of earthquake, the possibility of landslide and collapsing increased, so studying the dynamic performance of MSW is also the important task recently. The present research is supported by the National Science Foundation Project of Study on Municipal Solid Waste Landfill Solid, liquid and gas interaction and the mechanism of soil mechanics(No. 50538080), Study on residual deformation of MSW, dynamic shear modulus, damping ratio. And the residual deformation of MSW with degradation degree, dynamic shear modulus, damping ratio variation with the degree of degradation. The main contents of the research are as follows:By the use of medium-sized dynamic triaxial apparatus, municipal solid waste (MSW) experiments are conducted focusing on residual deformation, and improved Shen Zhujiang model parameters of the MSW were fitted. On this basis, the stress level effects on model parameters were studied under different failure criterion and the stress level indexes were recommended for MSW. MSW belongs to strain hardening-type material, and there is no obvious peak on stress and strain curve. Therefore, the same consolidation ratio of MSW has different stress levels under the conditions of the different failure criterion. In this paper, by replacing stress level with the consolidation stress ratio, a improved model was proposed for MSW. The modified model would be used conveniently without regard to different failure criterion.MSW is strain-hardening materials, so we have to define the failure criterion as the basis to determine the strength parameters beforehand. Here, we took the static test of different degrees of degradation of MSW, obtained the strength parameters under different failure criterion, and compared these parameters on different degrees of degradation. According to these parameters, we calculated stress levels with different degradation degree and different failure criterians, provided reliable data for modifying the model of residual deformation.For municipal solid waste in different degrees of degradation, we use the improved model for MSW residual deformation to derive the deformation parameters. Compared the consolidation ratio, degradation degree, the dynamic stress and other factors on the influence in residual deformation parameters. In the improved model, re-established the index value of consolidation ratio, which make it more applicable to different degrees of degradation of the residual deformation of MSW.Dynamic shear modulus and damping ratios of municipal solid waste in different degrees of degradation are also different. We study the different degrees of degradation of MSW in using cyclic triaxial test, define different dynamic shear modulus, damping ratio parameters, and provide the basis for the dynamic model.