一、概述随着科学技术的发展,桥梁的钻孔灌注桩越来越长,直径也越来越大。作为成孔机具,在国外,正循环钻机基本上已被反循环钻机所代替;在国内,浅孔已多用反循环钻机,而深孔大多还用正循环钻机,反循环钻机还没普及。正循环钻机与反循环钻机钻出的孔,质量差别很大,正循环钻机钻出的孔,附着其上的泥浆套厚而松,成孔时间长,清孔困难,沉淀层厚, First, an overview With the development of science and technology, the bridge’s bored pile longer and longer, the diameter is also growing. As a hole making tool, abroad, the circulating drilling rig is basically replaced by a reverse circulation drilling rig. In China, shallow holes have been used with reverse circulation drilling rigs, and most of the deep holes also use positive circulation drilling rigs. Reverse circulation drilling rigs have not yet become popular. The holes drilled by the circulating drilling machine and the reverse circulation drilling machine are of very different quality. The holes drilled by the circulating drilling rig are loosely and loosely coated with the mud on the drilling rig, the time for forming the holes is long, the holes are difficult to clear, the thickness of the sedimentation layer is thick,