基于两种回归场的SPR误差评估在地震液化数值分析中的比较与应用

COMPARATION AND APPLICATION OF THE SPR ERROR ESTIMATION BASED ON TWO RECOVERED FIELDS IN NUMERICAL ANALYSIS OF SEISMIC LIQUFACTION

在采用有限元方法数值模拟饱和砂土场地地震液化及流动的过程中,由于可液化砂土本构关系的非线性及土与结构接触的复杂性,在动力荷载增量很大时,网格易发生剧烈变形,导致计算结果缺乏需要的精度甚至中止计算。因此,需在计算中进行误差评估,获悉计算精度,为改善网格、优化最终计算结果提供依据。基于详细的SPR误差评估方法的原理和操作流程,比较了两种回归场在典型的液化流动数值案例中的结果和误差分布;结合液化程度、位移矢量分布等讨论了造成误差值大小差异的具体原因,既为数值分析提供可供参考的计算精度,也为进一步优化有限元计算提供合理依据。

In the finite element numerical simulation of seismic liquefaction and flow on the saturated sand ground, the mesh deforms strongly when the dynamic load increment is large, because of the complexity of the sand constitutive relationship and the soil-structure contact. Such calculation gives poor results without a desired accuracy, and even breaks off. Therefore, to improve the mesh and to optimize the final results, error estimation is required as a basis in the finite element calculation. According to the principle and procedure of the SPR （Superconvergent Patch Recovery） error estimation, the results and error distributions of two recovered fields in typical numerical examples on liquefaction and flow are compared; the reasons to the value differences of the errors are discussed, considering the liquefaction levels and the displacement vectors distribution. This error estimation can provide a referenced calculating accuracy, and a reasonable basis to improve the finite element calculation.