METHOD AND APPARATUS FOR DIRECTIONAL BORING UNDER MIXED CONDITIONS

摘要

A drill head for an apparatus for horizontal directional drilling. The drill head includes a device for detecting angular orientation, a holder for the device for detecting angular orientation, the device for detecting angular orientation being disposed therein, a hammer driven by a liquid and a drill bit. The holder, the hammer and the drill bit are connected head to tail along a longitudinal axis of a drill string with the holder at a proximate end of the drill head and the drill bit at a distal end of the drill head.