New model for analyzing the critical value of waste collapse allows landfill capacity to be expanded by 30%
Science and Technology Daily (Reporter Jiang Yun, intern Xin Jingjing, correspondent Shi Congshan) "This theoretical model based on 62 global cases can expand the capacity of landfills by 30% and effectively extend its service life." In China Association for Science and Technology At the scientific and technological achievements release conference of "Scientific Landfill Green Future" hosted recently, the scientific research project "Urban Domestic Waste Landfill Stability Analysis Key Soil Mechanics Parameters Test System and Application" by Professor Zhang Zhenying from School of Architecture and Engineering of Zhejiang Sci-Tech University attracted attention.
"In addition to recycling and incineration, in our country, about 60% of the garbage is disposed of in landfills." Zhang Zhenying introduced that the general landfill height of domestic garbage landfills can reach more than 100 meters, if protective measures Improper and irregular landfills can easily cause instability and collapse of the landfill, leakage and leakage of landfill leachate, as well as the escape and even deflagration of landfill gas generated by the degradation of domestic waste.
In mechanics, the higher the pile and the higher the slope, there will be a critical slip surface. When the height or shape of the slope reaches the critical value, it will trigger collapse and landslide failure.
By studying 62 cases of instability and destruction of landfills around the world, Zhang Zhenying’s team analyzed the changes in the shear strength of domestic waste at the sliding interface and the permeability of leachate, and established the shear strength of domestic waste based on this. Theoretical models and prediction theoretical models related to pressure, compressive strain, degradation time, etc. provide accurate soil mechanics parameters for the stability analysis of municipal solid waste landfills.
“The composition of domestic waste is extremely complex, highly heterogeneous, and multi-scale. It is easy to degrade over time and lead to changes in properties such as shape, volume, and quality.” In order to effectively analyze the soil mechanics parameters of domestic waste, Zhang Zhenying’s team overcame traditional soil testing instruments. Small size and other defects, large-scale geotechnical testing equipment that simulates the degradation process of garbage has been developed, invented and manufactured, and a large number of geotechnical experiments have been conducted.
"At present, the team has established cooperative relations with more than 20 cities across the country." Zhang Zhenying said, but the ideal goal is to sort the waste and reduce the amount of waste landfilled from the source.