A.1.5%~2.5% B.1.5%~2.5% C.0.5%~1.5% D.0.05%~0.159%
A.6 B.7 C.8 D.9
A.设计值 B.标准值 C.准永久值 D.永久值
A.1区砂 B.2区砂 C.3区砂 D.4区砂