Abstract Soil-cement columns are widely used to improve soft ground, and the bearing capacity of the formed composite ground is a key design parameter. The currently employed design method was developed for composite grounds under rigid footings, whilst the bearing capacity behavior of composite grounds under earth fills with different degrees of stiffness has rarely been investigated. Hence, the present study attempts to fill this gap. In this investigation, 1-g laboratory model tests are conducted to compare the bearing capacity behavior of composite grounds under a rigid footing and under embankment fill, based on which a numerical model that can capture the strain-softening behavior of soil-cement columns is established. The calibrated numerical model is further employed to perform 144 analyses. The results indicate that the failure mode of composite grounds differs for different types of earth fills: soil failure occurs prior to column failure under soft clay and dredged slurry, whereas column failure is the primary failure mode for composite grounds under embankment fill. This difference in failure mode of composite grounds can be explained using soil arching theories. For different failure modes, different bearing capacity efficiency factors should be used in design.

中文翻译：

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填土下水泥土柱复合地基承载力：物理和数值模拟

摘要 水泥土柱广泛用于软弱地基的改良，成型复合地基的承载力是一个关键的设计参数。目前采用的设计方法是针对刚性基础下的复合地基开发的，而对不同刚度填土下复合地基的承载能力行为很少进行研究。因此，本研究试图填补这一空白。在这项调查中，进行了 1-g 实验室模型试验，以比较刚性基础和路堤填充下复合地基的承载能力行为，在此基础上，可以捕获水泥土柱应变软化行为的数值模型是已确立的。校准后的数值模型进一步用于执行 144 次分析。结果表明，复合地基的破坏模式因不同类型的填土而不同：软粘土和疏浚泥浆下的土壤破坏先于柱破坏，而柱破坏是路堤填充下复合地基的主要破坏模式。这种复合地基破坏模式的差异可以用土拱理论来解释。对于不同的失效模式，设计时应采用不同的承载效率系数。