地震液化问题研究进展

概括了地震液化问题研究的框架和主要内容.从液化的机理、液化可能性分析, 液化稳 定分析、液化变形分析及液化分析的数值方法等几个方面, 总结了液化问题的主流研究思路 和近期进展, 指出了目前的不足和应着重研究的方向.随着对地震液化问题研究的深入, 液 化问题研究的重心逐渐由液化可能性分析、液化稳定分析转向液化引起的变形评价.在液化 变形的评价方法中, 基于震害调查的经验统计方法的预测精度较差, 且不能考虑土与结构的 相互作用;而基于数值模拟的方法可以考虑复杂的边值问题, 显示出广泛的前景.在以后对 地震液化问题的研究中, 除了进一步收集分析已有震害资料提高液化可能性分析及液化变形 分析的现有方法的可靠性以外, 应着重深入研究饱和砂土液化变形的基本规律及物理机制, 在此基础上建立能够合理模拟饱和砂土整个液化过程中(包括液化前和液化后)的应力应变 行为的本构模型, 发展能有效地预测实际边值问题中液化变形的数值模拟方法.

RECENT ADVANCES IN SEISMIC LIQUEFACTION RESEARCH

Main framework and topics of seismic liquefaction study are summarized,including the current state of the art and trends,with respect to mechanism of liquefaction,susceptibility of liquefaction,liquefaction flowslides,liquefaction-induced deformation and numerical modeling techniques.It is shown that the key issues of seismic liquefaction in practice are related not with strength but with deformation.The liquefaction-induced deformation evaluation techniques can be diveded into two categories:(1)empirical methods based on statis- tical analysis of historical seismic liquefaction deformation database and(2)numerical modeling.Numerical modeling is shown to be an effective tool and have widespread prospect for analysis of complex boundary value problems of seismic liquefaction.In future seismic liquefaction research,it is important to improve the existing methods of liquefaction susceptibility analysis and liquefaction-induced deformation evaluation by establishing and analyzing the seismic hazard database.But more emphases should be placed on revealing the mechanism of seismic liquefaction,developing constitutive models that can describe the stress-strain behavior of sand over a small to large strain range during an entire pre-and post-liquefaction process,and developing corresponding numerical algorithms to implement the models in the simulation of practical boundary-value problems.