砂性地基中防波堤地震残余变形机制分析与液化度预测法

海港工程中防波堤地震残余变形的预测以及震损机制的分析是较复杂的问题。采用定义在应变空间中考虑土体动主应力轴方向偏转影响的多重剪切机构塑性模型，分别从砂性土的黏粒含量和标贯击数2个主要影响因素对防波堤地震变形的变化机制进行了有效应力分析，得出防波堤较大的残余变形是由于地震作用下土体中孔隙水压力的升高致使土体软化而产生的。然后，采用液化度单一指标从物理本质上来间接表征防波堤的残余变形，得到防波堤残余变形与液化度之间的函数预测关系，预测值与震害调查值以及数值分析值基本相符，表明所得液化度预测公式具有一定的可靠性。残余变形的液化度预测法可为类似防波堤地震灾害设计与评价提供参考依据。

Mechanism analysis of residual liquefied deformation of breakwater during earthquake

The prediction of residual deformation and analysis of damage mechanism of breakwater are complicated problems in seaport engineering during earthquake. The nonlinear constitutive model of a multiple shear mechanism type in strain space is used in the study; and the effect of rotation of principal stress axis direction has been considered. The effective stress analysis of breakwater is given by considering both fine content of clay and equivalent SPT N-value; and some conclusions are achieved that the greater residual deformation of breakwater is induced by softened soil due to higher pore water pressure of soil. Then, the index of extent of liquefaction is applied to scale residual deformation of the breakwater; and the prediction relation of function is achieved between residual deformation and extent of liquefaction. The prediction values are close to investigation and numerical analysis values; it is shown that the function of prediction is credible. Some reference is provided by this prediction method of residual deformation by extent of liquefaction for similar breakwaters.