Constraints on the outer-core tangent cylinder using normal-mode splitting measurements     

Miaki Ishii  Adam M. Dziewo&#;ski 《Geophysical Journal International》2005,162(3):787-792

  相似文献   

桩基筒形翼状钻头的改进设计及应用     

杨建林  兰凯  段隆臣  张涛  徐辉雄 《地质科技情报》2005,24(Z1):19-22

针对浙江省温州市世贸中心大厦桩基施工中硬岩钻进时出现的堵管、卡钻和效率低等问题,从所钻地层和钻头的磨损分析出发,提出了钻头的改进设计方案.改进型筒形翼状钻头比原先使用的平底滚刀钻头增加了18个孕镶金刚石-针状硬质合金复合式钻齿和3个钎头,并按受力特点进行了合理分布.实际钻进效果表明改进型钻头应用于超深、大直径钻孔的钻进效率较高、钻进过程平稳.针对钻头的实际磨损情况提出了钻头进一步改进设计的建议.  相似文献   

旋挖钻进中硬岩及卵砾层钻头结构及施工工艺研究          下载免费PDF全文

张公正 《探矿工程》2005,32(2):40-42

旋挖钻进技术作为一种高效优质的钻进方法近年来广泛地被用于公路、铁路及大型水电站基础工程施工建设中，取得了良好的社会效益和经济效益。探讨了在卵砾石、漂石等复杂地层以及坚硬基岩中进行旋挖钻进所用钻头的结构及其施工工艺。  相似文献   

鄂 北 地 区 钻 头 优 选 探 讨          下载免费PDF全文

闫永辉 《探矿工程》2005,32(4):40-42

为适应鄂尔多斯塔巴庙区块勘探开发需要，利用区域测井资料进行钻头选型，并结合现场实践优化钻头类型和钻井参数，提高钻井效率。通过新型PDC钻头推广应用,单口井所需钻头数量减少3~4只，减少起下钻3回次以上，缩短钻井周期3~5天。  相似文献   

小动力旋挖钻机用嵌岩短螺旋钻头结构形式的改进          下载免费PDF全文

刘南昌  胡继良  黄玉文  翁炜  张宏智 《探矿工程》2005,32(2):43-43,46

采用小动力无加压旋挖钻机在粒径较大的卵砾石地层和泥页岩地层中进行1500 mm以上大口径钻孔灌注桩施工，由于钻机动力小且不能加压，用常规嵌岩短螺旋钻头钻进出现进尺慢或不进尺现象。通过对河南西峡县宛西制药责任有限公司新厂房桩孔施工过程中出现此种现象的分析和处理，提出了嵌岩短螺旋钻头针对性的改进措施，并取得了良好效果。  相似文献   

鄂北工区钻头型号及钻井参数的优化          下载免费PDF全文

李德红 《探矿工程》2005,32(8):50-54

通过对近年来鄂北工区所施工井的钻井资料进行分析、对比，优选出了适合于各区块、各井段的钻头型号和钻井参数，提高了机械钻速，缩短了钻井周期，使鄂北工区的钻井技术上了一个新的台阶，加速了鄂北气田的建设。  相似文献   

关于薄壁金刚石钻头胎体性能的探讨          下载免费PDF全文

王生福 《探矿工程》2005,32(11):57-58

对薄壁金刚石钻头胎体进行了性能分析和配方设计探讨，尤其根据被钻切介质对钻头胎体性能的要求作了较详细的分析，从理论分析结合实践经验筛选出了钻切建筑石材和各种钢筋砼的钻头胎体配方，在生产中满足了钻头工作条件的要求。  相似文献   

对我国金刚石钻头胎体经典配方的理论优化和建议          下载免费PDF全文

侯传彬  郭铁峰  张祖培  任锡钢 《探矿工程》2005,32(8):58-59

选取合理可信的约束条件对我国经典的63号金刚石钻头胎体配方进行了优化验证，获得理论认识，并依此对已有成熟配方的改进提出了建议。  相似文献   

Ice-core pollen record of climatic changes in the central Andes during the last 400 yr     

Kam-biu Liu  Carl A. Reese 《Quaternary Research》2005,64(2):272-278

This paper presents a high-resolution ice-core pollen record from the Sajama Ice Cap, Bolivia, that spans the last 400 yr. The pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age (LIA) consisted of two distinct phases—a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880. During the dry period xerophytic shrubs expanded to replace puna grasses on the Altiplano, as suggested by a dramatic drop in the Poaceae/Asteraceae (P/A) pollen ratio. The environment around Sajama was probably similar to the desert-like shrublands of the Southern Bolivian Highlands and western Andean slopes today. The striking similarity between the Sajama and Quelccaya proxy records suggests that climatic changes during the Little Ice Age occurred synchronously across the Altiplano.  相似文献   

Numerical simulation of percussive drilling          下载免费PDF全文

Alexandre Depouhon  Vincent Denoël  Emmanuel Detournay 《国际地质力学数值与分析法杂志》2015,39(8):889-912

This paper presents a novel dynamical model to analyze the long‐term response of a percussive drilling system. This departs from existing approaches that usually consider a single activation and bit/rock interaction cycle for the analysis of the process performance. The proposed model integrates the axial dynamics of an elastic piston and an elastic drill bit, a motion‐dependent pressure law to drive the piston, and a generalized bit/rock interaction law representative of the dynamic indentation taking place at the bit/rock interface. It applies to down‐the‐hole percussive drilling as well as top‐hole, with minor modifications. The model does not account for the angular motion or the hole cleaning, however. The model is first formulated mathematically; then, a finite‐dimensional approximation is proposed for computations. Numerical analyses of the model response, for a low‐size down‐the‐hole percussive system, follow. The period‐1 stationary response for the reference configuration is studied in detail, and parametric analyses assessing the influence on the rate of penetration of the bit/rock interaction parameters, the feed force, and the percussive activation parameters are conducted. These analyses reveal that the multiscale nature of the process is well captured by the model and recover expected trends for the influence of the parameters. They also suggest that a significant increase of the penetration rate can be achieved by increasing the percussive frequency. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献