既有线提速路基动应力分析

通过对既有线提速区段路基的调研和试验,得出结论,动应力与轴重、速度及线路平顺性有关。列车提速时,轴重增加和轨道不平顺对路基动应力影响最大。路基面动应力在横向呈马鞍分布,动应力沿深度方向衰减较快。采用当量折算和Boussinesq公式推算出的提速后路基动应力与实测值接近。在既有线提速改造中,重点应消除路基病害,提高基床特别是基床表层的强度和稳定性。

Dynamic Stress Analysis on Speed-increase Subgrade of Existing Railway

Survey and test were carried out on subgrade of speed-increase section on existing railway. It can be concluded that dynamic stress has something to do with axle load, speed and track regularity. The increase of axle load and track regularity are the key factors affecting the dynamic stress of subgrade as the speed of train increases. Dynamic stress is distributed as saddle along the lateral direction of subgrade surface. Dynamic stress along the depth declines sharply. Dynamic stress of subgrade after speed-increase is converted by equivalent weight and calculated by Boussinesq formula. It is found that the values are close to those of field tests. During speed-increase reconstruction of existing railway, the emphasis should be put on eliminating subgrade defects so as to improve the strength and the stability of subgrade bed, especially the surface layer of subgrade bed.