As a composite column, stiffened deep mixed (SDM) column is formed by inserting a precast concrete core pile into the center of a deep mixed (DM) column. The SDM columns have been successfully used to support highway and railway embankments and buildings over soft soil. However, there has been still a lack of feasible method to calculate the settlement SDM column-reinforced soft soil under an embankment load. This paper developed a theoretical solution to calculate the settlement of SDM column-supported embankment over soft soil. Based on the unit cell concept, the total settlement of the SDM column-reinforced soft soil consisted of three components, i.e., the compression of soil within the length of stiffened core pile, the compression of soil from the core pile base to the SDM column base, and the compression of soil below the SDM column base. The upward and downward penetrations of stiffened core pile were considered in the analysis. The analytical solution was verified by a comparison with the results computed by three-dimensional finite element analyses. A parametric study based on the derived solution was conducted to investigate the influence factors of modulus, length and diameter of DM column, length and diameter of core pile, and interface friction angle between DM column and core pile on the settlement of SDM column-reinforced soil, and some recommendations were proposed for its application in practice. The design charts for settlement calculation were developed for the ease of use in design. The design method was applied to two case histories of SDM column-supported embankments, and good agreements were found between the predicted settlements and the field measurements.

中文翻译：

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计算软黏土上加筋深层混合支护路堤沉降的设计方法

作为复合材料柱，可通过将预制混凝土芯桩插入深层混合（DM）柱的中心来形成加筋的深层混合（SDM）柱。SDM立柱已成功用于支撑高速公路和铁路路堤以及软土上的建筑物。然而，仍然缺乏可行的方法来计算路堤荷载下沉降SDM柱加筋的软土。本文提出了一种计算软土上SDM柱支撑路堤沉降的理论解决方案。基于单元格概念，SDM柱加筋软土的总沉降包括三个部分，即，在加硬芯桩长度范围内的土壤压缩，从芯桩基础到SDM柱的土壤压缩。底部以及SDM柱底部下方的土壤压缩。分析中考虑了加固芯桩的向上和向下穿透。通过与三维有限元分析计算的结果进行比较，验证了该解析解。基于导出的解进行参数研究，研究影响力系数，模量的长度和直径，芯桩的长度和直径，以及芯柱与芯桩之间的界面摩擦角对SDM筋加固的影响。土壤，并提出了一些建议，以便在实践中应用。制定了用于沉降计算的设计图，以便于设计使用。将该设计方法应用于SDM圆柱支撑路堤的两个案例历史，并在预测的沉降量和现场测量结果之间找到了良好的一致性。