filter layer

• 过滤层,渗透层

filter layer的用法和样例：

例句

1. It can be the filtration layer of the dikes,river canal,seacoast,concrete and retaining walls.
   可以做堤坝，河渠，海岸，混凝土，挡土墙的过滤层。
2. In drainage of agricultural lands, a filter or gravel envelope is used to prevent the entrance of fine sand and silt into the drains.
   在农田排水中常常采用砾石或过滤层来防止粉细砂和泥沙进入排水沟。