单桩复合地基上块体振动速度导纳的灵敏度特性

Sensitivity Analysis for Velocity Admittance of Block on Single-Piled Composite Foundation

简要分析了当前复合地基动测技术的不足,提出了用单桩复合地基上块体的竖向振动速度导纳曲线检测桩—土体系工程性状的机械导纳法.文中应用轴对称有限元—无限元耦合解,较系统地分析了块体速度导纳及其关于桩身弹性模量的灵敏度特性,包括地基土剪切波速、桩长和桩身缺陷的影响规律,对进一步完善复合地基动测技术以及用复合地基作动力机器基础时的优化设计具有重要的指导意义.

The conventional dynamic tests of composite foundation were reviewed and the velocity or mechanical admittance method for a block on single-piled composite foundation was recommended. By using the axis-symmetrical finite element-infinite element hybrid method, the sensitivity of mechanical admittance to pile modulus along pile shaft was numerically analyzed, including the effects of the shear wave velocity of subsoil and pile length as well as the defects of pile shaft. The conclusion will be of guide significance on further research of the proposed mechanical admittance method and on the design optimization for dynamic machines with composite foundations.