广义Gibson地基中单桩-土-承台共同作用简化分析

Simplified analysis for interaction of single pile-soil-cap in generalized Gibson soil

基于广义Gibson地基中单桩桩顶支承刚度和地基土支承刚度,结合单桩与承台间等效相互作用系数,建立了单桩–土–承台共同作用方程,提出了广义Gibson地基中单桩–土–承台共同作用简化分析方法。算例分析表明:简化分析结果与有限元分析结果、Butterfield解之间具有良好的一致性,验证了简化分析方法的合理性。参数分析表明:当桩的长径比l/d≥30,且承台与桩的半径比n≤4时,承台分担荷载较小,承台对带台单桩基础整体支承刚度的影响可忽略不计;弹性模量增加系数kE对带台单桩基础性状的影响比较明显,基础整体支承刚度与kE近似成线性增加关系。

Based on the supporting stiffnesses of single pile and soil as well as the equivalent interaction factors of pile-cap in nonhomogeneous soil, a single pile-soil-cap interaction equation was established. A simplified analytical approach was proposed to predict the behaviors of single pile-soil-cap in nonhomogeneous soil. The rationality of the proposed approach was shown by a good agreement between the results computed by the simplified analytical method and those of finite element methods and Butterfield approach. Parametric studies were presented. When the pile slenderness ratio l/d ≥30 and the cap-pile radius ratio n≤〈4, the percentage of load shared by the cap would be small, and the effect of the cap on the supporting stiffness of single pile-cap system might be negligible. There was obvious effect of the incremental coefficient of elastic modulus with the depth, kε, on the behavior of the single pile-cap foundation, and the relation between supporting stiffness of the single pile-cap system and kε was approximately linear.