Study on the Biodegradation Strength Properties for Municipal Solid Waste with Higher Content of Organic Matter

Basing on the new developed direct shear testing instrument, the biodegradation strength properties and strength parameters of municipal solid waste with higher content of organic matter have been studied. The municipal solid waste is divided into three parts: the material that is easy to be biodegraded, reinforced material that is difficult to be biodegraded and the incompressible solid waste material. The proportions of these three parts are 80%, 5% and 15%, respectively. A series of laboratory tests have been performed for different initial void ratios and different vertical pressures applied on the test specimen. Testing results show that the initial void ratio is the main influence factor for the biodegradation strength of the municipal solid waste, the relationship between the biodegradation shear stress and the shear strain is a strain hardening curve, the biodegradation shear stress gradually increases with the shear strain. Besides, the biodegradation shear strength shows a linear relationship to the vertical pressure applied on the test specimen, and it is in accordance with the law of coulomb. According to the testing results, the biodegradation shear strength parameters of municipal solid waste are obtained. The cohesion varies from 11.5 to 24.0kPa, and the internal friction angle varies from 8.3 to 29.0 degree.