1)unbraced excavation,无支撑挖掘2)braced excavation,支撑式挖掘3)un-timbered excavation,无支撑开挖4)lack of cutting force,挖掘无力5)braced excavation,支撑开挖6)sheeting for excavation,挖方支撑
用法例句
It is discovered that the two kinds of lack of cutting force and three reason of action slow.
