Settlement Of Municipal Solid Wastes

Sanitary landfill is one of the primary objects Environmental-geotechnics Engineering concerned. Settlement of Municipal Solid Waste (MSW) might influence directly the safety of sanitary landfill. Presently, its research is short of systematization. So, on the basis of fundamental laboratory experiments and theoretical research, a systematic frame is constructed, as a plane for further research. The main work of the thesis is as followed:(1) Mechanism Analysis. The thermodynamic mechanism and characteristics of settlement of MSW are set forth, and the difference between MSW and normal soil is analyzed. It is also put forward that it's always unsuitable to divide the settlement of MSW into primary and secondary compression phase artificially, but to divide it according to the engineering characteristics of MSW in landfill.(2) Laboratory experiments. Two apparatuses are designed for researching settlement of MSW. The samples are prepared manually for the sake of the comparability among experimental results. During the experiment, the settlement of MSW is observed for a long time, and the equilibrium of leachate under different leachating conditions is observed especially for analyzing the influence of leachate on the physical compressive settlement and decomposition settlement.(3) Theoretical Research. The estimating model of biodegradation settlement and compression (consolidation) settlement model of MSW are constructed respectively. Considering that biodegradation settlement of MSW is difficult to be observed directly, it's proposed to estimate the settlement according to the evolution of gas-production rate and dynamic equilibrium of leachate. The compression (consolidation) settlement models of MSW are tried to be constructed on some fundamental hypotheses according to the mechanism of settlement of MSW and the experiments. Considering the practical circumstance of MSW in the landfill, the rheological model of low-water-contented MSW settlement is pushed over primarily.