To drill soft, unconsolidated, usually shallow formations by eroding the "rock" below the bit by hydraulic impact loading alone.

钻进松软、非固结，通常是浅地层时，通过仅仅依靠液力冲击载荷去冲蚀破碎钻头下的岩石。

youdao

The paper describes a waterjet-aided drill which, successfully developed by Changsha Institute of Mining Research, is useful in laboratory and capable of drilling holes both in soft and hard rock.

本文介绍了长沙矿山研究院研制成的一种实验室用并适用于钻凿软至硬岩孔的连续水射流钻机及与其相适应的两种新型水力-刮刀钻头。

youdao

The bane that discussing the soft rock geologic strata closes to drill a hole badly and solve the method and measures, and put forward the actual suggestion within work.

论述了软岩地层封闭不良钻孔的危害及解决方法和措施，并提出了实际工作中的建议。

youdao