目前，在钻凿大口径钻井的工得中，国内外都广泛地采用牙轮钻头或圳力钻入钻凿的工艺方法，在各项工程中发挥着重要的作m。近年来，我国又研制了嵌岩基桩孔大口径游几锤．使得钻凿硬岩的时效提高了数倍。现正在研制试验中的”多头式”潜孔锤钻具较之“单头式”有更多优越性，固 At present, in the drilling of large-diameter drilling work, both at home and abroad have widely used roller cone bit or drill into the drilling process, in various projects play an important role m. In recent years, China has also developed a rock-based piles hole diameter a few swim tour hammer. Making the aging of hard rock drilling several times. Now under development test “long” DTH hammer than the “single head” has more advantages, solid