开挖线就是根据实际需要,使梯田挖、填方平衡(或有计划地留一差数)的一条分界线,比它高的地方为挖方区,比它低的地方为填方区。梯田施工时,常以这条线作水平标准。实践证明,只有正确测定开挖线,才能准确掌握挖填土方、修筑地坎的工程 Excavation line is based on the actual needs, make terraced fields digging, filling a balance (or a plan to leave a difference) of a demarcation line, higher than it for the excavation area, lower than it for the filling area. Terraced construction, often with this line as the standard. Practice has proved that only the correct determination of the excavation line, in order to accurately grasp the excavation of earthwork, construction ridge ridge project