underhole
n. 底部掏槽,底槽;下部掏槽
例句
Underhole drilling technology solved the difficulties of drilling in wet layers, deepened the drilling under water, and found an effective method of drilling hi pouring crushing layer.
潜孔锤泡沫钻进技术彻底攻克了潜孔锤在潮湿地层钻进的难关,加深了潜孔锤水下钻进的深度,找到了一条在涌水破碎地层进行潜孔锤钻进的有效途径。