• 2022-10-28
    允许速度大于120km/h的线路,无垫层时碎石道床厚度不得小于();有垫层时碎石道床厚度不得小于(),垫层厚度不得小于200mm。
    A: "450mm,300mm"
    B: "500mm,300mm"
    C: "450mm,400mm"
    D: "500mm,600mm"