锈蚀钢筋在疲劳荷载作用下压磁场分布研究

针对锈蚀钢筋的疲劳损伤与寿命评估中的难度大、精度低等问题,引入压磁检测技术,对锈蚀钢筋疲劳过程中的压磁场分布进行检测,从宏观与微观相结合的角度分析压磁场分布与疲劳损伤之间的联系。试验结果表明,锈蚀钢筋的压磁场分布能够反映疲劳损伤的演变规律,疲劳后期非线性特征加剧,锈蚀率及应力幅越大则变化越为明显,磁感强度值、磁场分布梯度、"反转"现象等均有助于进行疲劳损伤评价与寿命预测。研究结果可为压磁无损检测技术在钢筋混凝土结构中的应用提供依据。     

柴达木盆地北缘柴页1井中侏罗统大煤沟组页岩储层测井评价

页岩储层测井评价是后期压裂改造工程的基础,通过分析柴页1井常规测井曲线特征,结合特殊测井和岩心样品分析化验数据,综合评价了中侏罗统大煤沟组页岩岩性、物性、地球化学、含气性、可压裂性等特征,获得了储层评价及工程改造参数。柴页1井中侏罗统大煤沟组至少发育128.1m厚的富有机质页岩,具有高伽马、高声波时差、高中子、高电阻、低密度的特点;测井计算有利的富有机质页岩的总有机碳含量介于3.20%~4.20%之间,总含气量介于1.50~4.50m3/t之间,有利页岩层段脆性矿物含量介于45%~75％之间,划分出3个有利层组,第Ⅰ层组和第Ⅱ层组具有杨氏模量高、泊松比低的特点,有利于后期射孔压裂。     

柴达木盆地北缘侏罗系页岩气地质条件

侏罗系泥页岩是柴达木盆地的主力烃源岩之一,具备形成页岩油气的地质条件。对采自柴北缘鱼卡、大煤沟、小煤沟、开源、绿草沟、大头羊等煤矿附近地表露头的11块中侏罗统泥页岩样品进行单样品多参数实验分析,探讨了陆相页岩有机地化、储层物性、含气量等参数之间的关系,建立了页岩气资源评价参数体系。结果表明,柴达木盆地北缘中侏罗世处于浅湖-半深湖湖相沉积,断裂较发育,泥页岩富含有机质,具有低孔、低渗、低熟、较高含气量等特点,具备形成页岩油气的地质条件,进一步的勘查开发需优选地层压力系数高、保存条件较好、脆性矿物含量高的页岩气甜点区。     

对湖北大洪山地区一套紫红色砂-砾岩系沉积年代的再认识——碎屑锆石U-Pb年龄及其地质意义

湖北大洪山地区花山群六房咀组之上不整合覆盖了一套紫红色砂-砾岩。这套岩石的沉积时代存在争议,一种观点认为是南华纪早期;另一种观点认为是晚侏罗世。利用LA-ICP-MS分析技术,对这套碎屑沉积岩进行了碎屑锆石U-Pb测年,获得有效年龄数据125组,年龄值变化范围较大(3223~771Ma),主要集中于新太古代末—古元古代早期(约2500Ma)、古元古代(约2000Ma)和新元古代(约800Ma)3个时间段。对比鄂东南地区和三峡地区莲沱组岩石学特征和碎屑锆石年龄分布特征,认为其具有相似的物源,这套岩系沉积时代应该为南华纪早期而非晚侏罗世。综合分析扬子地块的前寒武纪年龄,认为扬子地块可能存在大量未岀露的新太古代末—古元古代早期(约2500Ma)基底,约2500Ma的岩石应该是扬子地块深部基底的重要组成部分。扬子地块存在广泛的古元古代(约2000Ma)岩浆活动,这期岩浆活动可能是Columbia超大陆聚合在扬子地块的响应。新元古代(约800Ma)扬子地块北缘存在Rodinia超大陆裂解同期裂谷,裂谷内基性岩可能为大洪山地区南华纪地层中基性岩砾石的物源。     

GNSS多系统组合精密定位研究进展

近年来,我国北斗卫星导航系统(BDS)以及欧洲伽利略卫星导航系统(GALILEO)正在快速建设与发展,同时,GPS和GLONASS卫星导航系统的现代化也在逐步推进,卫星导航定位领域正发生着深刻的变革。系统介绍了各卫星导航系统的建设和发展状况,探讨了多系统组合定位带来的机遇和面临的挑战,以及当前对这些问题的研究现状,最后对多系统组合定位的应用前景进行展望。     

Metallogeny of the Baiyangping Lead‐Zinc Polymetallic Ore Concentration Area,Northern Lanping Basin of Yunnan Province,China

The Lanping Basin in the Nujiang‐Lancangjiang‐Jinshajiang (the Sanjiang) area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of large unique sediment‐hosted Pb‐Zn polymetallic deposits or ore districts, such as the Baiyangping ore concentration area which is one of the representative ore district. The Baiyangping ore concentration area can be divided into the east and west ore belts, which were formed in a folded tectogene of the India‐Asia continental collisional setting and was controlled by a large reverse fault. Field observations reveal that the Mesozoic and Cenozoic sedimentary strata were outcropped in the mining area, and that the orebodies are obviously controlled by faults and hosted in sandstone and carbonate rocks. However, the ore‐forming elements in the east ore belt are mainly Pb‐Zn‐Sr‐Ag, while Pb‐Zn‐Ag‐Cu‐Co elements are dominant in the west ore belt. Comparative analysis of the C‐O‐Sr‐S‐Pb isotopic compositions suggest that both ore belts had a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata; the ore‐forming fluids were originated from formation water and precipitate water, which belonged to basin brine fluid system; sulfur was from organic thermal chemical sulfate reduction and biological sulfate reduction; the metal mineralization material was from sedimentary strata and basement, but the difference of the material source of the basement and the strata and the superimposed mineralization of the west ore belt resulted in the difference of metallogenic elements between the eastern and western metallogenic belts. The Pb‐Zn mineralization age of both ore belts was contemporary and formed in the same metallogenetic event. Both thrust formed at the same time and occurred at the Early Oligocene, which is consistent with the age constrained by field geological relationship.     

山东黄金西岭勘查区深部勘探孔防斜与纠斜措施

西岭勘查区金矿找矿工作已全面进入勘探阶段,勘查区网度为80 m×80 m,对于钻孔质量要求十分严格：终孔靶点偏差不超过勘探网度的四分之一,即不超过20 m。对于西岭勘查区设计孔深均超过1500 m（部分钻孔设计甚至超过2500 m）的钻孔而言,这种要求远远超过地质岩心钻探规程要求。山东黄金地勘公司根据多年深孔施工经验,在防斜与纠斜方面均取得了一些突破,自主研发了钻具扶正器、独创了钻孔纠斜法,形成了一套实用的钻孔质量保证措施。