砂心垫砂 bedding a core

垫砂起道 measured shovel packing

心型垫砂 bedding a core

稳芯垫砂 beddingacore

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

砂浆垫层 bedding mortar ; mortar bed

垫层砂浆 Bedding Mortar

砂垫 sand block