在沿海软土地区修建高重大建筑物，以及海洋工程中大型采油平台的建造中，所使用的桩一般具有较大的长径比，而长径比较大的桩易使桩侧土出现软化．当桩侧土出现软化后，使用常规设计方法确定的桩基承载力偏于不安全．基于修正的双曲线模型，推导了适用于桩侧土出现软化时群桩变形研究的计算公式．利用该算法能正确预估桩侧土出现软化后群桩的p -s曲线，从而为合理确定桩侧土出现软化时群桩的承载力提供理论依据．将该算法用于预估桩侧土出现软化后的现场实测群桩变形曲线，所得结果令人满意．

In construction of heavy, large and high-rise buildings in soft soil region along the coast, and the platform of ocean engineering, the piles used generally has large slender ratio. The pile that has large slender ratio often causes soil soften near the pile shaft. The bearing capacity of pile foundations determined by normal design code would become unsafe when the soil near pile shaft softens. Based on the modified hyperbolic curve model, a formula suitable for studying the pile groups deformations as the soils near pile shaft soften is deduced in this paper. The method can be used as a theoretical basis for determining the bearing capacity of pile groups as the soils near pile shaft soften. The predicted results using present method are in good agreement with the in situ deformation curve of pile groups as the soils near pile shaft soften.