Gao Wu, Xu Wenjie, Bian Xuecheng, Chen Yunmin
Department of Civil Engineering, MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China.
Waste Manag. 2017 Nov;69:202-214. doi: 10.1016/j.wasman.2017.07.048. Epub 2017 Aug 7.
The settlement of any position of the municipal solid waste (MSW) body during the landfilling process and after its closure has effects on the integrity of the internal structure and storage capacity of the landfill. This paper proposes a practical approach for calculating the settlement and storage capacity of landfills based on the space and time discretization of the landfilling process. The MSW body in the landfill was divided into independent column units, and the filling process of each column unit was determined by a simplified complete landfilling process. The settlement of a position in the landfill was calculated with the compression of each MSW layer in every column unit. Then, the simultaneous settlement of all the column units was integrated to obtain the settlement of the landfill and storage capacity of all the column units; this allowed to obtain the storage capacity of the landfill based on the layer-wise summation method. When the compression of each MSW layer was calculated, the effects of the fluctuation of the main leachate level and variation in the unit weight of the MSW on the overburdened effective stress were taken into consideration by introducing the main leachate level's proportion and the unit weight and buried depth curve. This approach is especially significant for MSW with a high kitchen waste content and landfills in developing countries. The stress-biodegradation compression model was used to calculate the compression of each MSW layer. A software program, Settlement and Storage Capacity Calculation System for Landfills, was developed by integrating the space and time discretization of the landfilling process and the settlement and storage capacity algorithms. The landfilling process of the phase IV of Shanghai Laogang Landfill was simulated using this software. The maximum geometric volume of the landfill error between the calculated and measured values is only 2.02%, and the accumulated filling weight error between the calculated value and measured value is less than 5%. These results show that this approach is practical for satisfactorily and reliably calculating the settlement and storage capacity. In addition, the development of the elevation lines in the landfill sections created with the software demonstrates that the optimization of the design of the structures should be based on the settlement of the landfill. Since this practical approach can reasonably calculate the storage capacity of landfills and efficiently provide the development of the settlement of each landfilling stage, it can be used for the optimizations of landfilling schemes and structural designs.
城市固体废弃物（MSW）体在填埋过程及填埋场封闭后的沉降，会对填埋场内部结构的完整性和存储容量产生影响。本文基于填埋过程的空间和时间离散化，提出了一种计算填埋场沉降和存储容量的实用方法。填埋场中的MSW体被划分为独立的柱状单元，每个柱状单元的填埋过程由简化的完整填埋过程确定。通过每个柱状单元中各MSW层的压缩来计算填埋场中某一位置的沉降。然后，对所有柱状单元的同步沉降进行整合，以获得填埋场的沉降和所有柱状单元的存储容量；这使得基于分层总和法能够得到填埋场的存储容量。在计算各MSW层的压缩时，通过引入主渗滤液水位比例以及MSW单位重量与埋藏深度曲线，考虑了主渗滤液水位波动和MSW单位重量变化对覆盖有效应力的影响。这种方法对于厨余垃圾含量高的MSW以及发展中国家的填埋场尤为重要。采用应力 - 生物降解压缩模型来计算各MSW层的压缩。通过整合填埋过程的空间和时间离散化以及沉降和存储容量算法，开发了一个软件程序——填埋场沉降与存储容量计算系统。利用该软件对上海老港填埋场四期的填埋过程进行了模拟。计算值与测量值之间填埋场最大几何体积误差仅为2.02%，计算值与测量值之间累计填埋重量误差小于5%。这些结果表明，该方法对于令人满意且可靠地计算沉降和存储容量是实用的。此外，利用该软件生成的填埋场剖面图中高程线的变化表明，结构设计的优化应基于填埋场的沉降。由于这种实用方法能够合理计算填埋场的存储容量，并有效地提供每个填埋阶段沉降的发展情况，因此可用于填埋方案和结构设计的优化。
