多级配砾石土反滤层工作机理及设计方法的研究，国内外均刚开始。

It has just begun to study the mechanism and design method of broadly graded soil filter.

youdao

多级配砾石土反滤层工作机理及设计方法的研究，国内外均刚开始。

It has just begun to study the mechanism and design method of broadly graded soil filter.

youdao