double-wall drill pipe meaning in English
双壁钻杆
Examples
- Under the function of big pressure and dynamic load , the grains may be moved which may cause the soil body distortion . at present , the relatively ripe methods of drill in gravel layer are mostly double - wall drill pipe reverse circulation drilling , auger stem breast wall drilling and down - the - hole hammer follow down drilling
论文根据jsl ? 30型砾石钻机潜孔锤同心跟管钻具结构,采用程序计算得到了钻杆内各深度处压力分布、钻头压力降、环形空间压力分布及空气流速分布。