Impact of Solidified Municipal Sludge as Temporary Covering Soil on the Stability of Landfill Slope

Abstract

Solidified municipal sludge is widely used as temporary covering soil in landfill. Due to the complex leachate of landfill, solidified municipal sludge has the problems of stagnant water and strength degradation. In order to investigate the influence of solidified municipal sludge on the stability of landfills, a landfill slope model with SEEP/W and SLPOE/W was established, using the actual infiltration as the boundary condition. Based on the changes in permeability and strength of the intermediate overburden layer, the migration law of leachate in a landfill under the condition of an intermediate overburden layer was analyzed. The relationship between landfill slope safety, climatic conditions and deterioration of the intermediate overburden layer was further explored. The results show that the permeability of the intermediate overburden layer affects the distribution of leachate and the height of stagnant water. During the rainstorm period, the safety factor of the landfill slope decreased rapidly from 1.4 to 1.0 or even lower. With the decrease in the shear strength of the intermediate overburden, the safety factor of the landfill slope was reduced to less than 1.0. Therefore, maintaining the permeability and strength of solidified municipal sludge at a certain level is required to ensure the safety and stability of landfill slopes.