查《铁路路基设计规范》(TB 10001—2005)表4.2.3,道床厚度h1=0.5m,h'1=0.35m
渗水土路肩高出非渗水土路肩尺寸
△h=(h1-h'1)+△=(0.5-0.35)+0.1=0.25m