液化地基中桩的破坏机理研究进展

地震诱发的地基液化对桩基础的破坏极大,液化地基中桩的破坏机理是岩土地震工程中的一个重要研究课题。目前地基液化时桩土结构系统的地震性态尚没有认识充分,已有的研究内容较多局限于桩身材料的强度破坏方面,难以考虑液化土体侧向流动、基桩屈曲失稳、以及土与结构动力相互作用等复杂因素的影响。本文重点加强以下3个方面的深入探讨和研究:(1)液化地基中桩的屈曲失稳;(2)液化地基中桩基破坏的数值模拟新方法;(3)液化地基中桩-土-结构的动力相互作用分析。

ADVANCES IN FAILURE MECHANISMS OF PILE FOUNDATIONS IN LIQUEFACTION SOILS

The earthquake-induced soil liquefaction can result in serious damages to pile foundations.Therefore,it is an important task to study the failure mechanisms of pile foundations in liquefaction soils in earthquake geotechnical engineering.Until now,the seismic behaviors of pile-soil-structure systems have not been fully understood yet.Most of current researchers are focused on strength failure of pile material,in which it is difficult to consider complex influencing factors such as lateral spreading of liquefying soils,pile buckling,and dynamic interaction between soil and structures.In this paper,firstly,a series of damage cases of pile foundations in liquefied soils are summarized from historical reports in Chian and abroad.Then,the failure mechanisms of pile foundations as well as research advances are introduced and analyzed in detail.Finally,aimed at liquefaction soils,it is pointed out that further investigations on the failure mechanisms of pile foundations should be strengthened on the following issues(1) pile buckling instability in liquefying soils;(2) novel numerical simulation methods for pile failures in liquefaction soils,e.g.continuum elasoplasticity-fluid dynamics coupled method;and(3) dynamic interaction analyses of pile-soil-structure systems in liquefaction soils.