考虑频响特性的均质梯形断面路基等效参数计算

以无砟轨道路基为主要研究对象，建立多个高度梯形断面均质路基及半无限空间的有限元动力计算模型，对路基及半无限空间在相同荷载作用下不同位置的动应力、动位移和加速度进行了频响特性对比分析。综合考虑各动力响应结果得出：除去边坡点，路基内大部分点的动力响应吻合度基本呈现随路基高度减小而有所增加的趋势，当路基高度小于3m时，吻合度可达到约80％；当路基高度为4～6 m时，吻合度可达到70％以上；当路基高度为8 m以上时，吻合度低于60％。根据不同的动力分析目的，达到满足分析精度要求的吻合度时，具有梯形断面的路基可以等效为半无限空间，其等效参数可以按照动力基础半空间理论进行计算。

Equivalent parameters calculation of trapezoidalsection of homogeneous subgrade considering frequency response characteristics

In this paper,ballastless track-subgrade is applied as the main research obj ect.The dynamic finite element models of multiple highly homogeneous trapezoidal section of subgrade and semi-infinite space are set up,and comparative analysis has been made to study the dynamic stress,displacement and acceleration frequency response characteristics in different locations of the subgrade and semi-infinite space under the same load.The result shows that,except the slope points,the goodness of fit for dy-namic response basic rendering with the trend of increased with the decrease of the subgrade height.When the subgrade height is less than 3 m,the goodness of fit can reach about 80%;when the height is between 4 m to 6 m,it can reach more than 70%;8 m height or bigger appears less than 60%.According to different purposes of dynamic analysis,when meeting the analysis preci-sion requirement,the homogeneous subgrade with a trapezoidal section can be equivalent to half infinite space,and its equivalent parameters can be carried out in accordance with the dynamic basic half space theory calculation.