新疆乌恰萨热克铜矿北矿带库孜贡苏组沉积相、古流向、物源区及其找矿意义——来自砾石统计分析的证据

萨热克盆地库孜贡苏组是萨热克铜矿的赋矿层位,开展沉积相、物源区及古流向研究对隐伏铜矿的勘探具有重要意义。选取萨热克铜矿北矿带库孜贡苏组地表矿化最好的砾岩展开砾石统计分析,结果表明,偏斜度显示砾岩为冲积扇相沉积,砾石叠瓦状和砂岩斜层理产状统计显示古流向为北北东向;砾石成分主要为石英、石英砂岩、砂岩,石英岩等;粒度分布呈宽峰态或尖峰态;物源区为元古宇长城系阿克苏群变质岩剥蚀区;物源补给分为主河流补给和支河流补给2种方式。冲积扇相、古流向、物源区分析确定了矿体的范围、最优的勘探线布置方位和潜在的找矿靶区,具有很好的勘探意义。     

蒙古科布多省阿拉腾索音博地区辉长岩LA-ICP-MS锆石U-Pb年龄及其地质意义

蒙古科布多省阿拉腾索音博地区地处阿尔泰构造带南缘,由一系列弧盆系及增生杂岩带组成。区内发育一条近东西向辉长岩带,辉长岩15颗锆石分为2类:一类具明显条带韵律环带,一类内部均匀干净,二者均不具核边结构,不含包体,结合高Th/U值(0.46~0.68),确定为典型的基性岩浆锆石;锆石LA-ICP-MS年龄加权平均值为317.6±1.6Ma,厘定其成岩时代为晚石炭世。研究对比表明,该辉长岩带形成于板块俯冲碰撞的尾声阶段,是阿尔泰造山运动大背景下区域基性岩浆活动的产物。     

西藏改则县多龙矿集区发现岩墙岭蛇绿岩残片

西藏班公湖-怒江缝合带北缘多龙矿集区是青藏高原新近发现的具有超大型远景的、典型的富金斑岩型铜矿集区,其成岩成矿地质背景是解决班公湖-怒江洋构造演化的关键问题之一。近年来的区域地质调查研究发现,多龙矿集区南侧出露岩墙岭蛇绿岩残片,应该是班公湖-怒江蛇绿岩带的重要组成部分。岩墙岭蛇绿岩主要由席状岩墙群、枕状玄武岩和硅质岩组成,整体呈棱形或透镜体状断续分布于侏罗系复理石沉积内,构成典型的网结状构造。糜棱岩普遍发育在岩墙岭蛇绿岩和围岩的接触部位。综合前人研究成果,初步认为多龙矿集区早白垩世成岩成矿作用应该形成于增生楔之上伸展拉张的构造环境。岩墙岭蛇绿岩的发现和确定进一步约束了多龙矿集区成岩成矿地质背景,同时为班公湖-怒江缝合带的延伸及其构造演化的研究提供了新的线索。     

基于兴趣区域的无参考型影像质量评价研究

针对现阶段无参考型算法主观一致性差的问题,提出了一种基于兴趣区域的无参考型影像质量评价算法(NROI),在德克萨斯大学的Live影像库中与经典算法:峰值信噪比(PSNR)、结构相似度(SSIM)、自然场景统计模型(NIQE)法,进行大量实验对比。结果表明,NROI的表现优于NIQE,PSNR与SSIM相当,适用于数字影像的质量评价。     

基于窗口移动中误差模型探测船载重力数据粗差

粗差探测是评价船载重力测量数据成果质量的重要内容。卫星测高反演重力场技术提供了海域全覆盖的重力场数值模型,其精度水平已满足探测船载重力测量数据粗差的精度要求。以卫星测高反演重力场模型为基础,提出了基于窗口移动中误差模型探测船载重力测量粗差的数据处理方法,其基本思路是:以卫星测高反演重力场数值模型作为背景场,计算船载重力测点处的测高重力值的差值,以差值作为输入量,等权构建中误差背景场,以开窗中误差背景场作为参考,按照平差思想探测船载重力测量数据的粗差。实验结果表明,依据本文方法能有效探测船载重力测量数据的粗差。     

浮托安装进船过程中护舷碰撞力实测研究

浮托安装法广泛应用于大型组块海上安装。导管架平台上部组块浮托安装进船过程中,风、浪、流引起的浮托驳船横向运动造成浮托驳船与导管架桩腿的碰撞,碰撞力可能会对导管架结构造成损伤。陆丰7-2上部组块浮托安装中,为了监测碰撞力大小,设计了碰撞力海上监测系统。通过在导管架外侧四个桩腿上安装光纤光栅应变传感器对碰撞过程中导管架桩腿进行应力监测,进而计算碰撞力。对碰撞过程,载荷作用位置、方向进行简化,并对载荷大小及垂向作用位置对计算的影响进行了研究。结构分析模型简化后,测点von-Mises应力与碰撞力大小成正比,对导管架整体结构建模计算并取局部结构计算比例系数,结合应力实测数据计算出进船过程中驳船对导管架桩腿碰撞力。     

Ultimate Bending Capacity of Strain Hardening Steel Pipes

Based on Hencky’s total strain theory of plasticity, ultimate bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material, the simplified analytical solution is proposed as well. Good agreement is observed when ultimate bending capacities obtained from analytical solutions are compared with experimental results from full-size tests of steel pipes. Parametric study conducted as part of this paper indicates that the strain hardening effect has significant influence on the ultimate bending capacity of steel pipes. It is shown that pipe considering strain hardening yields higher bending capacity than that of pipe assumed as elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the ultimate bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore/onshore steel pipes, supports of offshore platforms and other tubular structural steel members.     

Failure Pressure Analysis of Corroded Moderate-to-High Strength Pipelines

Based on the elastic-plastic, large-deformation finite element method, burst capacity of steel pipeline with longitudinal corrosion defect subjected to internal pressure is studied. The appropriate stress-based criterion is used to predict the failure pressure of finite element model of corroded pipeline under internal pressure. By considering the pipe steel grades and geometries of corrosion defects, a series of finite element analyses is conducted. The effects of corrosion depth, length and width on burst capacity are also discussed. A specific failure pressure solution for the assessment of corrosion defects in moderate-to-high strength pipeline is proposed on the base of numerical results. The failure pressures predicted by the proposed method are in better agreement with the experimental results than the results by the other methods.