【摘要】 根据工程实例 ,通过钻头和钻进工艺的对比试验 ,得出了利用大直径滚刀钻头 ,在致密卵漂石地层施工大口径桩孔 ,能大幅度提高钻进效率。更多还原

【Abstract】 According to th concrete examples,through comparative test between bit and drilling technology we came to the conclusing that the use of large diameter rolling-cutter-type bit could raise greatly the drilling efficiency wher large diameter bored piles are operated in the compact boulder bed.更多还原