不同含水率下脏污道砟累积塑性变形预测

Prediction of cumulative plastic deformation for fouled ballast under different moisture contents

为预测脏污状态下铁路有砟道床累积塑性变形,采用循环加载三轴试验和修正次加载面模型对循环荷载作用下脏污道砟的累积塑性变形发展规律开展了研究。试验结果表明,细粒含量及含水率协同影响道砟的水力和力学性能,特别是当道砟中细颗粒含量和含水率都增长时,道砟的力学性能显著下降,进而加剧了循环荷载下铁路道砟累积沉降的发展。此外,基于次加载面本构模型并借助有限元软件,二次开发编写了修正次加载面模型子程序,通过对比室内试验结果验证了该模型的适用性。数值模拟结果表明,修正次加载面模型可以较好地预测不同含水率和细粒含量影响下铁路道砟的累积塑性变形。因此,可在未来研究中借助修正次加载面模型建立实尺铁路道床分析模型,预测不同脏污条件下铁路有砟道床的累积沉降。

To predict the cumulative plastic deformation characteristics of ballasted tracks under contaminated conditions,we utilized cyclic loading triaxial tests and a revised subloading surface model to investigate the cumulative plastic deformation characteristics of fouled ballast under cyclic loading.The findings revealed a synergistic effect of fine fraction content and moisture content on the hydro-mechanical properties of ballast.Particularly,simultaneous increases in fine fraction content and moisture content lead to a continuous decline in the mechanical properties of ballast,exacerbating the cumulative settlement of railway ballast under cyclic loading.Additionally,a modified subprogram for the subloading surface model was developed based on its constitutive theory and finite element software.The model’s validity was confirmed through comparison with results from cyclic loading triaxial tests.Numerical simulations demonstrated that the proposed model effectively predicts the evolution of cumulative plastic deformation of railway ballast under varying moisture and fine fraction content.Hence,the revised subloading surface model can be applied in future studies to establish a comprehensive engineering analysis model for predicting the long-term settlement of railway tracks under different fouled conditions.