基于Ohde理论的群桩极限端阻力计算公式

为从理论上探讨群桩中桩-土-桩的相互作用,分析该作用对群桩端阻力形成机理的影响,以建立在压缩机理之上的适用于单桩端阻力分析的Ohde理论为基础,提出了无黏性土中群桩极限端阻力的计算模式,据此分别推导出了群桩中边桩和中桩的极限端阻力理论计算公式.该公式能够定量反映桩距、桩径、桩端的入土深度和桩端以下土层的物理力学性质等因素对极限端阻力的影响,计算得到的群桩极限端阻力随相对桩距(桩距与桩径之比)减小而增加的规律与模型试验的实测结果基本一致.

Base resistance of pile groups based on Ohde's approach

In order to study the effect of pile-soil-pile interaction on the mechanism of pile base resistance in pile groups,a calculating model is proposed for the ultimate tip bearing capacity of a pile group in cohesionless soil based on the Ohde's pattern derived from the compression mechanism for a single pile.From this model an approach is derived to evaluate respectively the ultimate base resistance of an individual outside pile or an individual inside pile in a pile group.In this theoretical procedure,the influence on the ultimate pile tip resistance is taken into account by the pile spacing,pile diameter,pile embedding length and the properties of the soil below the pile tip.The pattern given by the theoretical formula that the pile base bearing capacity increases with the relative pile spacing(the ratio of pile spacing to pile diameter)decrease agrees with that measured in a model test.