(中南工業(yè)大學(xué)資源、 環(huán)境與建筑工程學(xué)院， 長(zhǎng)沙 410083)
摘 要: 三峽工程在硬巖中施工d 175 mm倒垂孔，為預(yù)防孔斜需要采用超低壓鉆進(jìn)(最低鉆壓只有1.8 MPa)。 為此， 開(kāi)發(fā)研制了一種金剛石與胎體之間有一弱結(jié)合層的新型鉆頭。 由于該種鉆頭新、 舊金剛石的新陳代謝換層速度較普通鉆頭快， 其抗打滑能力極強(qiáng)。 現(xiàn)場(chǎng)鉆進(jìn)試驗(yàn)結(jié)果表明， 該新型鉆頭不僅能克服鉆頭打滑， 而且機(jī)械鉆速和鉆頭壽命均有顯著提高， 綜合指標(biāo)提高幅度達(dá)2.06倍。
關(guān)鍵字: 硬巖 超低鉆壓 孕鑲金剛石鉆頭 弱結(jié)合層
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
