砂垫层 sand mat ; sand cushion ; sand bedding course ; sand blanket

排水砂垫层 sand mat of subgrade ; drainage sand mat ; drainage sand blanker ; sand filled drainage layer

路基砂垫层 sand mat of subgrade

三角砂垫 Triangular Sanding Pad

砂垫层流失 loss of sand cushion

垫砂 placing sand

砂浆垫层 bedding mortar ; mortar bed

冰砂垫 ice sand pad