近断层脉冲型地震下建筑地桩基础沉降分析

Settlement Analysis of Building Pile Foundation Under Near-fault Pulse-like Ground Motions

传统基于碰撞回弹系数Stereo-mechanical方法在分析建筑地桩基础的沉降位移过程中未考虑地桩基础碰撞的能量损耗,造成分析结果存在准确性和可信度较低的问题。因此提出改进的Kelvin建筑地桩基础碰撞沉降分析方法,以解决基于碰撞回弹系数Stereo-mechanical法存在的问题。采用线性阻尼构建Kelvin模型,分析地桩基础碰撞靠近阶段和回弹阶段的阻尼做功,构建地桩基础碰撞转换单自由度体系振动模型,实现对地桩基础的相对沉降速度和相对沉降位移的有效运算,基于建筑地桩基础碰撞沉降发生初始和结束时刻的能量和动量守恒定理,得到建筑地桩基础的最大沉降位移,实现对建筑地桩基础沉降的有效分析。实验结果说明,所提方法能提高地桩基础沉降分析的准确性和可信度。

In the traditional stereo mechanical method based on the collision resilience coefficient, the energy loss caused by pile foundation collision is not considered in the analysis of settlement and displacement of building pile foundation, resulting in low accuracy and reliability of the anal ysis results. Therefore, this study proposes an improved Kelvin settlement analysis method for building pile foundation collision to solve this existing problem in the stereo mechanical method. The Kelvin model is established with linear damping to analyze the damping of the pile foundation during the close and rebound stages of collision. The pile foundation collision is then transformed into the vibration of a single degree of freedom system. The vibration model is established to real ize the effective calculation of relative settlement velocity and relative settlement displacement of the pile foundation. The maximum settlement displacement of the pile foundation is calculated based on the conservation laws of energy and momentum at the initial and end moments of the pile foundation collision settlement. The results indicate that the proposed method can improve the accuracy and reliability of the settlement analysis of the ground pile foundation.