sand-gravel layer 砂砾石层
sand gravel layer 砂卵石地层
sandy gravel layer 砂卵石层
thick gravel layer 巨厚卵石层
boulder-gravel layer 卵砾石层
sand and gravel layer 砂卵石垫层
deep overburden gravel layer 深覆盖厚卵砾石层
C. Vibration strike: it is used in drilling and casing with loosen sand, cobble stone and gravel layer etc.
振动击打：用于松散的砂、卵石、碎石地层的钻进及下套管等。
There have three decisive questions need to solve while drilling in sand gravel layer. The first question is drilling footage.
在砂卵石地层中勘察钻探时，要解决三个关键性的问题：一是钻进进尺问题；
The invert siphon project in Zhongyishui lies in the sand and gravel layer, with rich groundwater and high seepage coefficient.
中易水倒虹吸工程建筑物所处地层为砂卵层，地下水丰富，渗透系数大。
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