An attenuation layer composed of ground mixed with stabilising agents can prevent the contamination of the surrounding area when using soils and rocks with geogenic contaminants in embankments. The optimum particle size of the stabilising agent must be selected based on the requirements of the construction site because the mechanical and chemical properties of the attenuation layer are site-specific. However, the relationship between the particle size of the stabilising agent and the attenuation performance of soil–agent mixtures has yet to be fully clarified. This study employs batch sorption tests to evaluate the attenuation of arsenic by a soil mixed with a calcium–magnesium composite with different particle sizes, ranging from powder particles (<0.075 mm in size) to granular particles with diameters between 2.0 and 9.5 mm. Amended soil more effectively attenuates the contaminant than the original soil. In one experiment, a stabilising agent of granular particles (between 2.0 and 9.5 mm) for the amendment increased the soil’s partition coefficient K_d from 14.5 to 22.2 cm³/g, which is more than a 50% improvement in the attenuation. Using a stabilising agent with a smaller particle size for the amendment has a greater impact. K_d increases linearly as the particle size of the stabilising agent decreases down to 0.075 mm. Using the K_d from laboratory tests, simulations with a one-dimensional advection–dispersion equation demonstrate the durability of the attenuation layer. Both the powder and the granular particles show promise as attenuation layer materials.

当在路堤中使用带有地质污染物的土壤和岩石时，由混合有稳定剂的地面组成的衰减层可以防止对周围区域的污染。稳定剂的最佳粒径必须根据施工现场的要求来选择，因为衰减层的机械和化学性能是因场地而异的。然而，稳定剂的粒径与土剂​​混合物的衰减性能之间的关系尚未完全阐明。本研究采用批量吸附测试来评估土壤对砷的衰减，该土壤与不同粒径的钙镁复合材料混合，从粉末颗粒（尺寸 <0.075 毫米）到直径在 2.0 和 9.5 毫米之间的颗粒颗粒。改良土壤比原始土壤更有效地减少污染物。在一项实验中，用于改良的颗粒状颗粒（介于 2.0 和 9.5 毫米之间）的稳定剂增加了土壤的分配系数K _d从 14.5 到 22.2 cm ³ /g，衰减提高了 50% 以上。使用粒径较小的稳定剂进行修正影响较大。K _d随着稳定剂的粒径减小到 0.075 mm 呈线性增加。使用来自实验室测试的K _d，使用一维平流 - 色散方程的模拟证明了衰减层的耐久性。粉末和粒状颗粒都显示出作为衰减层材料的前景。