Abstract This paper presents a case history of the settlement performance of a railway embankment built on a Prefabricated Vertical Drain (PVD) improved soft alluvial soil of Karakore area, Wollo province, north-east of Ethiopia. The embankment was constructed on Awash - Kombolcha - Haragebaya (AKH) railway project for the purpose of preloading so as to facilitate the consolidation settlement in a short period of time; and it was monitored for more than 750 days. Numerical predictions of Class A and Class C (based on back-calculation procedure) were performed using Plaxis 2D. The soft soil creep (SSC) model was employed for the soft soil layers, while the Mohr-Coulomb (MC) model was used for the drainage and fill layers. The predictions were compared with the field monitoring settlement data. Quite a reasonable agreement was achieved from the finite element modelling of Class C prediction when the prediction was compared with the actual field settlement values. Parametric sensitivity studies were carried out to examine the influence of parameters on the rate and magnitude of settlements. The results of the numerical predictions and parametric studies have been discussed in detail. The soil on the flood plain area of Karakore is found to be very soft to soft alluvial deposit and formed over Tertiary Eocene stiff clay. The variable conditions of the soil formation and deposition highly dictated the deformation and excess pore water pressure behaviour of the soft subsoil sediment. The parametric sensitivity study showed that, following the compression index, the initial void ratio, the hydraulic conductivity, and the OCR highly influenced the settlement responses of PVD-improved soft alluvium soil respectively.

中文翻译：

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PVD改良的Karakore软质冲积土上铁路路堤的沉降

摘要 本文介绍了埃塞俄比亚东北部 Wollo 省 Karakore 地区在预制垂直排水沟 (PVD) 改良软质冲积土上建造的铁路路堤沉降性能的案例历史。该路堤建于Awash-Kombolcha-Haragebaya（AKH）铁路项目上，以预压为目的，便于短时间内固结沉降；并对其进行了 750 多天的监控。使用 Plaxis 2D 执行 A 类和 C 类（基于反向计算程序）的数值预测。软土层采用软土蠕变（SSC）模型，排水层和填土层采用莫尔-库仑（MC）模型。预测结果与现场监测沉降数据进行了比较。将预测值与实际现场沉降值进行比较，C 类预测的有限元模型得到了相当合理的一致性。进行了参数敏感性研究，以检查参数对沉降速率和大小的影响。已经详细讨论了数值预测和参数研究的结果。卡拉科雷洪泛区的土壤被发现是非常柔软的冲积沉积物，形成于第三纪始新世坚硬粘土之上。土壤形成和沉积的可变条件高度决定了软底土沉积物的变形和超孔隙水压力行为。参数敏感性研究表明，随着压缩指数、初始孔隙比、水力传导率、