相互作用体系中桩基的动力响应

Dynamic response of pile foundation in interaction system

率先在国内开展了对一种新型变截面桩-土-高层建筑结构体系动力相互作用的试验研究。通过振动台模型试验,观察了桩-土-结构体系动力相互作用的现象,验证和掌握了新型桩体与结构的震害特点。根据试验测定的数据,研究了支盘桩-高层建筑结构体系的动力特性和地震反应,重点分析了支盘桩的动力响应。通过计算和分析得出:桩-土接触压力时程曲线揭示了在地震动激励下桩-土之间存在着拉开和再接触的现象,表明支盘桩在动力相互作用过程中承受了拉、拔荷载,说明和证实了当基础具有较大的抗拉、抗拔和抗扭曲能力时,才能更好的发挥动力相互作用体系的抗震性能和减轻震灾;桩基两侧对应测点的应变时程曲线呈反向关系,表明在地震作用下,相同时间内桩基一侧受拔,另一侧受压,解释了地震区房屋产生倾斜、倾倒震害现象的根本原因。

An experimental research on dynamic interaction of pile-soil-structure system was first developed in China. Phenomena of the dynamic interaction of the system were observed, so earthquake damage characteristics between a new type of pile and structure were verified and discovered by shaking table test. Dynamic characteristics and seismic response of the system were studied, and dynamic response of squeezed branch piles was analyzed based on the test data. It was shown by calculation and analysis that the separating and reclosing phenomena occurred between pile and soil under the action of the seismic exciting force, not only revealing that squeezed branch piles were pulled up and pressed down in the course of dynamic interaction, but also explaining and verifing that seismic capability and reduced earthquake damage would be obtained in the dynamic interaction system only when the foundations had greater pulling, pressing and twisting resistant capability. Phenomena of pulling up on one side and pressing down on the other side in the pile foundation were revealed according to reverse direction relation of time-course curve from the corresponding measure points on the sides of pile foundation under seismic action at the same time, and it explained essential reason why the buildings were inclined and toppled in the seismic region.