Centrifuge Model Test On Stress Characteristic Of Geomembrane Placed On Landfill Slopes

With the improvement in the urbanization level, the generation of municipal solid waste increases rapidly in China. The safety of landfill liner system is greatly threatened due to the complexity of the environment around it. Liners placed on landfill slopes may suffer great tension and damage as a result of large settlement of waste, especially in valley landfill. If the tension of the liner exceeds the strength of the liner material, the liner system will be broken, seriously affecting the surrounding environment of the landfill. Therefore, it is important for safe operation of the landfill and the lives and property of the residents around to study the force condition of the liner system, calculate the magnitude of the force and propose a optimized structure type of liner system.Considering the complexity of the composition of the liner system, the geomembrane which is the the most important component is chosen to be studied. Model waste and model geomembrane have been prepared, and six centrifuge model tests are conducted. The first four groups mainly study the geomembrane from aspects of the slope angle, interface strength and compression of the waste, and the results showed that:Geomembrane has tension zone and compression zone which is separated by the neutral point, and position of the neutral point is affected by gradient and settlement; Gradient and waste settlement are important factors to affect the development of tension; the tension is very small when the upside of geomembrane is smooth while the downside is rough because the external force is difficult to pass to the internal. The last two groups aim to study the effect of drainage layer and position of the landfill cell, and the results showed that:the presence of the drainage layer can greatly reduce the tension of geomembrane, and position of the landfill cell has great effect on force condition of geomembrane.The FLAC analysis model is built, and the simulation results show that:Settlement affects tension by changing mobilized interface strength; The presence of the drainage layer can greatly reduce the tension of geomembrane; Geomembrane of the central landfill cell is in the most dangerous state; The presence of anchoring platform has greatly decreased tension in geomembrane.Finally, the modified limit equilibrium method is used to calculate the tension of geomembrane which is better fit with the experimental results, and Shenzhen Xiaping landfill is chosen as an example.