Abstract

This study is to analyze geotechnical properties and biological status of undisturbed municipal solid waste (MSW) associated with depth by using a large-diameter borehole sampling method. Through the method, a 28 m-borehole with 0.8 m of the diameter was drilled into the MSW body consisting of ten-lift layers of waste placed over 4000 days in an operating landfill. MSW sample cuttings were collected from the field site, weighted, and transferred to a laboratory for additional experiments to measure various properties such as moisture content, constituent characterization, unit weights, specific gravity, decomposition state, saturation, and compression rates with regard to waste depth. Also, the methane production obtained from MSW decomposition tests indicated that waste mass was relatively consistent throughout the depth of borehole and had not reached the accelerated production phase of methane. The wet and dry unit weights of the MSW sample with different depths produced excellent trends of the first-order rate with vertical stress. First Oder Rate Equation (FORE) analysis indicated that the maximum total and dry unit weight of MSW (γ_MSWw and (γ_MSWd) achieved at depth in the waste mass were 12.9 kN/m³ and 10.6 kN/m³, respectively. Based on the waste shrinkage ratio (WSR) defined as the initial dry unit weight divided by succeeding dry unit weight, the height of the original MSW pile was estimated to be 40.5 m. Different compression parameters, including aggregated MSW compression index (C_c), modified compression index (C_CE), and compression ratio parameter (C_c’), were comparably evaluated, which can be beneficial to understand compressibility and settlement processes in a landfill.

摘要

这项研究是通过使用大口径钻孔方法分析与深度相关的未扰动城市固体废物的岩土特性和生物学状态。通过该方法，将直径为0.8 m的28 m钻孔钻入MSW主体，该主体由十层提升的废物层组成，这些废物层在运行中的填埋场中放置了4000天。从野外现场收集生活垃圾样品碎片，称重，然后转移到实验室进行其他实验，以测量各种性质，例如水分，成分特征，单位重量，比重，分解状态，饱和度和废物压缩率深度。也，从城市固体废弃物分解试验获得的甲烷产量表明，在整个井眼深度，废物质量相对稳定，没有达到甲烷的加速生产阶段。不同深度MSW样品的湿重和干重在垂直应力下产生了一级速率的极好的趋势。首次Oder Rate方程（FORE）分析表明，城市固体废弃物的最大总和干重为（γ废物质量在深处获得的_MSWw和（_γMSWd）分别为12.9 kN / m ³和10.6 kN / m ³。根据定义为初始干燥单位重量除以后续干燥单位重量的废物收缩率（WSR），原始MSW桩的高度估计为40.5 m。比较地评估了不同的压缩参数，包括汇总的城市固体废弃物压缩指数（C _c），修正的压缩指数（C _CE）和压缩比参数（C _c '），这对于理解垃圾填埋场的可压缩性和沉降过程可能是有益的。