(中南工业大学资源、 环境与建筑工程学院， 长沙 410083)
摘 要: 三峡工程在硬岩中施工d 175 mm倒垂孔，为预防孔斜需要采用超低压钻进(最低钻压只有1.8 MPa)。 为此， 开发研制了一种金刚石与胎体之间有一弱结合层的新型钻头。 由于该种钻头新、 旧金刚石的新陈代谢换层速度较普通钻头快， 其抗打滑能力极强。 现场钻进试验结果表明， 该新型钻头不仅能克服钻头打滑， 而且机械钻速和钻头寿命均有显著提高， 综合指标提高幅度达2.06倍。
关键字: 硬岩 超低钻压 孕镶金刚石钻头 弱结合层
FORMATIONS WITH ULTRA-LOW BIT PRESSURE
IN THREE GORGES PROJECT
（College of Resources, Environment and Civil Engineering,Central South University of Technology, Changsha 410083, P. R. China
）
Abstract:In Three Gorges Project, the d175 mm inversely perpendicular holes were required to drill in hard granite with ultra-low bit pressure (the minimum bit pressure was only 1.8 MPa). In order to prevent the hole deviation, a new concept bit with weak binding layer between diamonds and matrix has been developed, which has very high anti-slipping performance, because the metabolism of new bit between worn, blunt diamonds and new, sharp diamonds can occur sooner than that of traditional bits. Field drilling experiments in Three Gorges Project showed that the new bits could not only overcome bit slipping but also improve the penetration rate and bit service life, the composite index of them increased 2.06 times.
Key words: hard formation ultra-low bit pressure impregnated diamond bit weak binding layer
