Question

一段防洪堤的横截面如图.已知CD=10m,AC的坡比（CE与AE的比）为2:1,BD的坡比为1:2,堤高CE=4m,要修

Answer 1

CE:AE=2:1,

AE=CE/2=4/2=2(m);

DF=CE=4m,

DF:BF=1:2,

BF=2DF=2*4=8(m);

EF=CD=10m,

横截面的面积=梯形CABD的面积

=(CD+AB)*CE/2

=(CD+AE+EF+FB)*CE/2

=(10+2+10+8)*4/2

=60(m²)

要修筑500m这样的防洪堤,共需土石:

=横截面的面积*长

=60*500

=30000(m³),[1方=1立方米=1m³]

要修筑500m这样的防洪堤,共需30000土石方.