考虑龄期分层的固体废弃物填埋场边坡稳定分析

固体废弃物填埋场长期使用过程中，垃圾土的强度参数随着龄期的变化而变化。在进行固体废弃物填埋场边坡稳定分析时考虑按龄期分层，基于极限分析上限理论，提出了转动-平动组合和多块体平动两种破坏机构。通过水平分层土坡算例的对比分析，验证两种破坏机构的合理性和有效性。进而对填埋场算例按龄期分层分析，结果表明，极限分析上限解的安全系数和破坏机制与强度折减有限单元法非常接近，多块体平动机构通过随机搜索所得的最危险滑裂面优于转动-平动组合机构。最后分析西班牙Coll Cardús固废填埋场，此填埋场是按龄期分层的典型复杂填埋场，运用两种破坏机构所得的安全系数和最危险滑裂面与有限单元法相符。算例分析表明，在不考虑水位的情况下，填埋体堆填时间越长越有利于填埋场的稳定。当填埋体按低、中、高龄期分层形成时，填埋场的整体稳定安全系数介于中龄期和高龄期的均质边坡之间。

Stability analysis of a municipal solid waste slope layered by aging

During the long-term service period of the municipal solid waste (MSW) landfill, the strength parameters of the waste body change as time elapses. In analyzing the stability of the MSW fill, we decompose the waste body into layers according to the age, and propose two failure mechanisms based on the upper bound theorem of limit analysis, including the rotational and translational mechanisms. To confirm the above two mechanisms, a comparative analysis is performed on a slope composed of horizontally soil layers, and then the case of the landfill slope layered by aging is analyzed by assuming the two mechanisms above. It is shown that the factor of safety and failure mechanism by the upper-limit solution of limit analysis are very close to those deduced from the reduction finite element analysis, and the critical failure mode obtained by the multi-block mechanism is more reasonable. In addition, the stability of the Coll Cardús MSW landfill in Spain with complex layers by aging is analyzed, and the results are consistent with those of the reduction finite element analysis. Our results indicate that, as the fill age increases, the landfill slope will become more and more stable in the absent of pore pressures. The fill age can be divided into low, middle and high levels. The safety factor of the landfill slope layered by aging is between those of the homogeneous slopes with middle to high aging levels.