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推导了一种列车动荷载下基于蠕变本构方程的长期沉降计算方法。首先根据列车通过轨道时引起激振力,利用半无限空间Mindlin解求出轨道正下方任一点的列车移动荷载引起的动应力,其次采用波尔兹曼线性叠加原理和积分原理推导出动应力蠕变本构方程,然后将列车移动荷载引起的动应力代入动应力蠕变积分方程,推导出列车动荷载蠕变应力–应变积分方程,最后结合分层总和法计算出列车运行引起的长期沉降。并采用数值模拟和实测数据对本算法进行有效性验证,结果表明:推导的用于计算列车运行引起的长期沉降的半解析法计算结果与实测数据比较吻合,此半解析法忽略了间接作用轮对的影响,其计算结果相比于数值模拟结果偏小,但间接作用轮对长期沉降的影响很小,在工程上可以忽略不计。
A long-term settlement calculation method based on creep constitutive equation under dynamic loads was derived. First of all, the dynamic stress caused by train moving loads at any point directly below the track is obtained by means of Mindlin solution in semi-infinite space according to the excitation force when the train passes through the track. Second, the dynamic stress creep is derived by applying the principle of Boltzmann linear superposition and the integral principle Then, the dynamic stress caused by train moving loads is substituted into the creep integral equation of dynamic stress, and the creep stress-strain integral equation of train dynamic load is deduced. Finally, the long-term settlement caused by train operation is calculated by the hierarchical summation method. The numerical results show that the calculated results obtained by the semi-analytical method for calculating the long-term settlement caused by train operation are in good agreement with the measured data. The semi-analytical method ignores the indirect wheel set The results of the calculation are smaller than those of the numerical simulation, but the effect of the indirect action wheel on the long-term settlement is very small and can be neglected in engineering.