中硬岩层 meaning in English

medium ground

Soft - medium hard rock formation
软-中硬岩层
Wedge hob drill head is applicable for medium harden rock layer , coarse grain granite , and it has below 9 - grade drillability . the compressive strength is no more than 10 of pull coefficient
楔齿滚刀钻头适合于中硬岩层，粗晶花岗岩，可钻性9级以下，抗压强度在普氏系数10 。
Drill efficiency could be promoted sharply in penetration of high - medium hard sand rock rock formation . its wings are of higher wear resistance and impact efficiency . to repeat repair grind are not necessary
大幅提高中硬岩层砂岩的钻进效率,刀翼耐磨抗冲击性强,不需反复修磨,钻头寿命长。
The present situation of many areas lack water seriously in china and execution of strategy of national geology survey makes it become urgent assignment that how to drill soft - middle hard rock rapidly and with high efficiency encountered frequently in drought and water - scarce area
摘要中国许多地区严重缺水的现状及国家地质大调查战略的实施，使得如何快速、高效钻进干旱缺水地区大量遇到的软中硬岩层成为当务之急。