有事为了克服以上缺点改用钻孔灌注桩和后压浆灌注桩，但灌注桩在砂土地层中也不易钻进，常出现卡钻、掉钻；
Sometimes, in order to overcome these shortcomings to use bored piles and post-grouting pile, but bored piles are difficult to drilling in sand stratum, drill pipe sticking and dropping often appears;
浮鞋的内部（包括锥型段部分）通常由水泥或热塑性材料组成，如果在套管鞋处井眼还需要继续加深的话这种材料必须被钻掉。
The inside (including the taper) is usually made of cement or thermoplastic, since this material must be drilled out if the well is to be deepened beyond the casing point.
牙医把她牙齿上蛀坏的部分钻掉。
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