Stone columns have attracted considerable attention as a ground improvement techniques recently. Performance of stone columns, however, depends on confining pressure offered by the surrounding soils. In the case of very soft soils, the lateral confining pressure may be insufficient and this may lead to column bulging failure. Encapsulating the individual stone column enhances the lateral resistance against bulging by additional confining pressure. In this study, the influences of the length of encasement and type of aggregate materials on the bearing capacity of a single stone column in both dry sand and clay bed were investigated. The results indicated a clear improvement by encasing the half-length of the column. The numerical study also showed the effect of reinforcement stiffness reduces with increase in the cohesion of the clay. Parametric study showed that the effect of encasement stiffness is insignificant for clay bed with high values of cohesion.

中文翻译：

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围岩柱承载力的试验与数值研究

石柱作为近来的地面改良技术已经引起了相当大的关注。然而，石柱的性能取决于周围土壤提供的围压。在土壤非常软的情况下，侧向约束压力可能不足，这可能导致色谱柱膨胀失败。封装单个石柱可通过附加围压提高侧面抵抗膨胀的能力。在这项研究中，研究了包裹长度和骨料类型对干砂和黏土层中单个石柱承载力的影响。结果表明，通过包裹色谱柱的一半长度可以明显改善。数值研究还表明，增强刚度的影响随着粘土内聚力的增加而降低。