研究目的：在津秦客运专线地质勘察过程中,当遇到松散、破碎或者软弱夹层,采用常规钻探手段时,由于岩芯受到冲洗液的冲刷、钻具振动、岩芯管内的摩擦,岩芯采取率极低,甚至导致岩芯烧坏、污染、原结构破坏等情况,不能满足地质勘察和规范要求,因此必须改进钻探工艺。
研究结论：(1)经钻孔生产试验证明,单动双管金刚石钻具能防止冲洗液冲刷、减少钻具振动,保持岩芯原结构,从而避免岩芯污染、烧坏; (2)采用单动双管金刚石钻进方法,提高了岩芯采取率,最高达91%,使岩芯采取率全部达到地质规范设计要求; (3)在单动双管钻具使用过程中,仍存在一定问题,还需进一步在生产试验中摸索改进。
Research purposes：In the course of the geological survey for Tianjin-Qinhuangdao Passenger Dedicated Line, the core-drilling ratio was very low in unconsolidated and fracture strata or in soft inter layer, even the rock core was burnt, polluted and its structure was damaged when using conventional drilling techniques because the rock core suffered the wash of the fluid, vibration of the drilling bit and the friction of the inner tube. It could not meet the railway prospecting criterion, so the drilling technique must be improved.
Research conclusions：(1) The applicable test of drilling showed the Single-acting Double-tube diamond bit could prevent the wash of the fluid, reduce the vibration of the drilling bit and remain the original core structure, therefore to avoid the pollution and burnt damage to the rock core. (2) Application of the Single-acting Double-tube diamond bit could enhance the core-drilling ratio to 91% maximally and the core-drilling ratio could meet the the railway prospecting criterion. (3) There were some problems in using the Single-acting Double-tube diamond bit, so the method of using Single-acting Double-tube diamond bit still could be improved in further tests and applications.
PDF(510 KB)
