Facies model of a fine‐grained,tide‐dominated delta: Lower Dir Abu Lifa Member (Eocene), Western Desert,Egypt

Existing facies models of tide‐dominated deltas largely omit fine‐grained, mud‐rich successions. Sedimentary facies and sequence stratigraphic analysis of the exceptionally well‐preserved Late Eocene Dir Abu Lifa Member (Western Desert, Egypt) aims to bridge this gap. The succession was deposited in a structurally controlled, shallow, macrotidal embayment and deposition was supplemented by fluvial processes but lacked wave influence. The succession contains two stacked, progradational parasequence sets bounded by regionally extensive flooding surfaces. Within this succession two main genetic elements are identified: non‐channelized tidal bars and tidal channels. Non‐channelized tidal bars comprise coarsening‐upward sandbodies, including large, downcurrent‐dipping accretion surfaces, sometimes capped by palaeosols indicating emergence. Tidal channels are preserved as single‐storey and multilateral bodies filled by: (i) laterally migrating, elongate tidal bars (inclined heterolithic strata, 5 to 25 m thick); (ii) forward‐facing lobate bars (sigmoidal heterolithic strata, up to 10 m thick); (iii) side bars displaying oblique to vertical accretion (4 to 7 m thick); or (iv) vertically‐accreting mud (1 to 4 m thick). Palaeocurrent data show that channels were swept by bidirectional tidal currents and typically were mutually evasive. Along‐strike variability defines a similar large‐scale architecture in both parasequence sets: a deeply scoured channel belt characterized by widespread inclined heterolithic strata is eroded from the parasequence‐set top, and flanked by stacked, non‐channelized tidal bars and smaller channelized bodies. The tide‐dominated delta is characterized by: (i) the regressive stratigraphic context; (ii) net‐progradational stratigraphic architecture within the succession; (iii) the absence of upward deepening trends and tidal ravinement surfaces; and (iv) architectural relations that demonstrate contemporaneous tidal distributary channel infill and tidal bar accretion at the delta front. The detailed facies analysis of this fine‐grained, tide‐dominated deltaic succession expands the range of depositional models available for the evaluation of ancient tidal successions, which are currently biased towards transgressive, valley‐confined estuarine and coarser grained deltaic depositional systems.     

SYZX75型绳索取心液动锤在肃北德勒诺尔铁矿区的应用

介绍了SYZX75型绳索取心液动锤在甘肃省肃北县德勒诺尔铁矿区坚硬、破碎地层中的应用情况,总结了该钻具在斜孔施工中的经验。实践表明,使用SYZX75型绳索取心液动锤,大幅度提高了回次进尺和钻进效率;有效克服了破碎地层的岩心堵塞,提高了破碎地层岩心采取率;有助于斜孔施工中的孔斜度控制。     

新疆温宿、库车地区砂岩铀矿绳索取心钻探技术

介绍了在新疆温衍县、库乍县煤田和砂岩型铀矿钻探施工中,将绳索取心钻进技术应用于沉积岩和软岩地层施工的技术措施及效果。实践农明,绳索取心钻进技术在沉积岩和软岩地层同样可以发挥钻进效率高的优势。     

中深孔直斜两用轻便钻塔的研制及应用

在调研国产立轴式岩心钻机的基础上,经过充分论证,提出了直、斜两用钻塔的设计方案。直、斜两用钻塔的成功研发,解决了国产立轴式岩心钻机不宜施工斜孔的问题,拓展了国产立轴式岩心钻机的使用空间。介绍了该钻塔的设计思路、结构设计及其生产试验效果。     

倾斜地球同步卫星的轨道演化分析

利用STK软件对倾斜地球同步卫星的轨道进行仿真,给出了主要轨道参数的演化曲线,经分析发现：倾斜地球同步卫星的轨道是比较稳定的,可以满足卫星寿命期内对轨道相对稳定的要求。     

北京冯家峪铁矿坑道水平硬岩钻进技术实践

北京冯家峪铁矿地层坚硬致密、研磨性较弱、构造发育、易造斜、岩性复杂,坑道水平钻进中钻孔倾角变化范围较大（-55°～60°）,上仰孔施工中冲洗液易沿着钻杆流出并对施工人员、钻机设备造成较大危害,硐内安全生产隐患较多,这些都给钻进施工带来了较大困难。对此,选用主机质量轻、所需安装空间小的Z7559型全液压钻机,选取满眼组合钻具,定制软胎体金刚石钻头;合理选用、调整冲洗液性能及泵量,正确调整钻进工艺参数;采取限制回次进尺、合理安装钻机等措施,确保工程质量和施工安全。对坚硬地层大倾角硐内水平钻进施工具有一定的借鉴意义。     

倾斜与偏心荷载作用下裙板式基础破坏包络面研究

联合采用Swipe加载模式与固定位移比加载模式,对裙板式浅基础在倾斜与偏心荷载两种加载条件下的承载性能进行了比较系统的平面应变有限元分析,主要探讨了裙板式基础埋深、地基土不排水强度的非均质性对基础在竖向荷载V与水平荷载H、竖向荷载V与弯矩M加载平面内的破坏包络面的影响,揭示了地基在不同荷载分量组合条件下的失稳破坏机制。结果表明,基础埋深与地基土强度的非均质性对于地基失稳模式有较大影响,但V-H和V-M平面内的破坏包络面形状具有较好的归一化特性,并分别建议了裙板式基础在倾斜和偏心荷载作用下的破坏包络面方程。     

定向控制爆破技术在斜井掘进中的应用

文章论述在斜井掘进中采用定向控制爆破技术 ,利用最小抵抗线原理 ,即最小抵抗线方向是爆破作用和岩石移动的主导方向 ,使石渣向后抛掷 ,以充分利用耙斗装岩机工作 ,从而大大提高工作效率 ,降低工人的劳动强度。     

高雷诺数下均匀振荡流中倾斜桩柱上的水动力特征研究

本文介绍了均匀振荡流中光滑倾斜桩柱上（α＝４５°）水动力特征的试验研究及其与水平桩柱（α＝９０°）研究结果的对比。     

Interpretation of ground VLF-EM data in terms of inclined sheet-like conductor models

The response of two-dimensional, inclined, sheet-like conductors with, low conductance values to plane wave electromagnetic fields in the very low frequency (VLF) range has been evaluated by using a numerical technique. The conductance values of the conductors considered are appropriate for those produced by water and/or clay-filled fracture and shear zones in the Precambrian crystalline rocks of the Canadian Shield. The surrounding host rock was assumed to be, resistive with resistivities in the 1–10 k.m range to reflect the high resistivities over the shield areas. No overburden was assumed in this analysis.The results of the computations are presented in the form of characteristic interpretation diagrams to interpret ground VLF data in the field, where facilities for direct numerical modelling may not be available. A method for interpreting ground VLF data using such characteristic diagrams has been proposed in this paper which requires a prior knowledge of the host rock resistivity and the inclination of the conductor. These two parameters may be derived from a VLF resistivity survey and from appropriate filtering of the VLF tilt angle response. The interpretation method was applied to a ground VLF anomaly obtained at a research site near Atikokan in NW Ontario, which yielded an interpretation compatible with information from geological mapping.Geological Survey of Canada Contribution No. 51888.