drainage sand blanket

例句：

1. 1. The engineer designed adrainage sand blanket to improve the soil's permeability.
   工程师设计了一个排水砂垫层来提高土壤的透水性。
2. 2. During construction, the builder used drainagesand blankets to prevent water from seeping into the foundation.
   在施工期间，建筑商使用排水砂垫层以防止水渗入地基。
3. 3. The sand blanket was crucialin preventing soil erosion and maintainingthe stability of the slope.
   沙垫层在防止土壤侵蚀和保持斜坡稳定性方面至关重要。