Abstract The effectiveness of the prefabricated vertical drains (PVDs) in the consolidation of ultra-soft dredged soil with various soil water contents (W) in Mae Moh mine, Lampang, Thailand was researched via a series of large-scale model tests and numerical analysis. Large settlements with the delay of excess pore pressures is a distinct behavior of ultra-soft soil. The PVD dimensions were found to have a significant effect on the rate of consolidation and the delay of excess pore pressure at low total vertical stress (σv). The smaller PVD dimension resulted in the smaller rate of consolidation and longer delay of excess pore pressure. The undrained shear strength (Su) of ultra-soft clay at various degrees of consolidation could be approximated by the vertical effective stress (σ′v) based on the SHANSEP where the σ′v was determined from the Asaoka's observational method. The finite element analysis with axisymmetric and plane strain models showed that the axisymmetric model produced an excellent settlement prediction. However, the excess pore pressures were not well predicted by the axisymmetric model, due to the delay of excess pore pressures at the early stages of consolidation. In practice, the plane strain models proposed by Chai et al. and Indraratna and Redana's methods are suggested to predict the consolidation settlement of the Mae Moh dredged soil improved with PVD. The outcome of this research will facilitate the geotechnical design of reclamation of ultra-soft dredged soil in Mae Moh mine and other similar soils.

中文翻译：

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泰国 Mae Moh 矿用预制垂直排水管改善疏浚超软土的固结行为

摘要 通过一系列大型模型试验和数值分析，研究了预制垂直排水沟 (PVD) 在泰国南邦 Mae Moh 矿区不同土壤含水量 (W) 的超软疏浚土壤中的固结效果。 . 具有超孔隙压延迟的大型沉降是超软土的一种独特行为。发现 PVD ​​尺寸对固结速率和低总垂直应力 (σv) 下超孔隙压力的延迟有显着影响。较小的 PVD ​​尺寸导致较小的固结率和较长的超孔隙压力延迟。超软粘土在不同固结度下的不排水抗剪强度（Su）可以通过基于 SHANSEP 的垂直有效应力（σ'v）来近似，其中 σ'v 由 Asaoka 的观测方法确定。使用轴对称和平面应变模型的有限元分析表明，轴对称模型产生了极好的沉降预测。然而，由于超孔隙压在固结早期的延迟，轴对称模型不能很好地预测超孔隙压。在实践中，柴等人提出的平面应变模型。建议使用 Indraratna 和 Redana 的方法来预测 PVD ​​改良的 Mae Moh 疏浚土壤的固结沉降。