层状异性流变地层桩基长时位移的理论预测

Theoretical Prediction of Long-term Displacement of Pile Foundation in Layered Anisogenous Rheological Strata

摘要:

针对层状异性流变地层中桩基长时沉降位移预测计算难题，基于荷载传递模式、Poyting-Thomson模型和土体一维虚拟结构等效模型，建立了该类地层中桩基承载模式判别以及桩基服役全过程长时沉降位移的理论预测方法。研究了稳定蠕变地层桩基承载模式演变及其沉降位移时效特性。结果表明:摩擦承载状态下桩基沉降呈现瞬态弹性；土体的层状异性特型导致桩体压缩变形具有明显的台阶突变；摩擦+桩端共同承载时，桩基总体位移等于桩体形变位移和桩端沉降位移的叠加，具有显著时效特性并随时间逐步趋于稳定。

Abstract:

In response to the difficulty of predicting the long-term settlement displacement of pile foundations in layered anisotropic rheological strata, a theoretical prediction method for the bearing mode discrimination of pile foundations in this type of strata and the long-term settlement displacement of pile foundation throughout its service process is established, which is based on the load transfer mode, Poyting-Thomson model and one-dimensional virtual structure equivalent model of soil. The evolution of bearing mode and the settlement displacement time response characteristics of pile foundation in stable creep strata are studied. The results indicate that the settlement of pile foundation under the frictional bearing state presents the transient elasticity. The layered anisotropy of the soil leads to a significant step mutation in the compression deformation of the pile body. When the friction and the pile end are jointly supported, the overall displacement of the pile foundation is equal to the superposition of deformation displacement of pile body and the settlement displacement of pile end, which has the significant time effect characteristics and gradually stabilizes over time.