CFRP加固一字形竖缝耗能预制剪力墙抗震性能研究

以一字形竖缝耗能预制剪力墙作为研究对象,设计了3个装配式剪力墙试件及1个现浇剪力墙对比试件,进行低周往复荷载试验,并对破坏墙体进行CFRP加固,再次进行拟静力试验。试件变化参数包括轴压比、混凝土强度等级及配筋率,对比分析加固前后试件滞回性能、刚度退化、承载力和耗能能力等性能。试验结果表明,与现浇剪力墙相比,一字形竖缝耗能预制剪力墙工作性能良好,阻尼器屈服耗能提高了试件整体工作性能;CFRP加固可有效抑制墙体斜裂缝的发展,对墙体承载力及耗能能力均有显著改善作用;各试件均满足剪力墙弹塑性层间位移角限值要求,延性较好;试件整体表现出良好的抗震性能。     

广西田东县那矿金矿区地质与地球化学特征及找矿方向

广西田东县那矿金矿位于滇黔桂金三角,属于卡林型金矿。本文在对那矿金矿区进行1∶10000地质填图的基础上,基本上查明了其成矿地质背景,结合1∶10000土壤地球化学测量,选取Au、As、Sb三种元素为成矿指示元素。通过土壤地球化学数据分析,对矿区内指示元素异常的特征、分布与地质现象进行对比分析,进行异常解释评价。研究结果显示:那矿金矿区中三叠统百逢组中上部粉砂质泥岩、泥岩、泥质粉砂岩是赋矿层位;坡表谷背斜与坡表谷断裂的复合部位为成矿有利部位;硅化、(褐)黄铁矿化、毒砂矿化、高岭石化、绢云母化、碳酸盐岩化等蚀变为金的矿化标志;圈定的Ⅰ号异常带是矿致异常,其Au元素异常规模大、品位高,是该区找矿的重点靶区。     

丝绸之路经济带甘肃黄金段找矿勘查新进展

丝绸之路经济带已成为国家战略,赋于了上合组织新的内涵,也给地质工作者提出了新的要求。甘肃是古丝绸之路的锁匙之地,是丝绸之路经济带上的“黄金路段”。2014年甘肃省提出利用拥有古丝绸之路贯穿境内1600 km的战略通道优势,打造丝绸之路经济带的黄金段,使其成为向西开放的战略平台、经贸物流的区域中心、产业合作的示范基地、人才交流的桥梁纽带。本文就甘肃省矿产资源优势、找矿勘查新进展及向西走出去提出建议。     

矿床成矿系列——五论矿床的成矿系列问题

矿床的成矿系列(简称成矿系列)是矿床学领域的一个理论性概念,由五级序次组成。矿床成矿系列是成矿系列的第二序次,是成矿系列的核心部分。矿床成矿系列的划分,以岩浆、沉积、变质、表生和流体(非岩浆-非变质成因流体)5种成矿作用为基本原则,以成矿地质环境为基础,结合成矿的时段与形成的矿床组合进行划分。本文对矿床成矿系列时空范围、时空组成结构、矿化强度与演化、成矿区带内不同矿床成矿系列之间的演化、叠加和复合作用及对指导找矿的意义进行了论述。     

Seismic attenuation estimation using a complete ensemble empirical mode decomposition-based method

The frequency attenuation gradient method can provide important information for hydrocarbon detection. In this paper, a method using Complete Ensemble Empirical Mode Decomposition (CEEMD), Hilbert transform and the least-squares curve-fitting is proposed for seismic attenuation estimation as an effective frequency attenuation gradient estimation approach. We first use CEEMD to obtain the different Intrinsic Mode Functions (IMFs), which have a narrow band and can enhance the physical meaning of instantaneous attributes trace by trace. The time-frequency spectrum, which is computed using a Hilbert transform of each IMF, is represented as a spectrum with a single-peak that has narrow side lobes, which is conducive to frequency attenuation gradient estimation. Second, for each time sample, the frequency-amplitude spectrum of each IMF trace is extracted from the time-frequency spectrum to conduct the attenuation gradient computation. Then, the logarithm operation is performed for each IMF trace. Due to the very narrow bands of some IMFs in some seismic traces, a variable frequency window is adopted along the IMF trace according to the local data characteristics. Finally, the attenuation gradient for each IMF in a seismic trace can be computed using least-squares fitting. A different IMF reflects a seismic trace with a different spatiotemporal scale and can highlight different geologic and stratigraphic information. The correlation weighted average operation is used to highlight some useful details in seismic trace and obtains the attenuation gradient for each seismic trace. Field data examples demonstrate our method and its effectiveness. The proposed method can stably estimate the frequency attenuation gradient.     

滇西盈江地区新泡山离子吸附型稀土矿床成矿条件及找矿前景

滇西盈江地区是近年来离子吸附型稀土矿床找矿突破较大的地区,典型代表为腾冲岩浆弧内新发现的新泡山稀土矿床,为一中型离子吸附型稀土矿床,是滇西高海拔地区新发现的典型矿床。新泡山稀土矿床的发现对今后高海拔地区的找矿工作具有重要的示范意义。通过对新泡山稀土矿床的地质特征、风化壳结构特征、矿体垂向变化特征进行研究,认为新泡山稀土矿床类型为富钕轻稀土离子吸附型稀土矿床,并伴生有重稀土钇。滇西盈江地区与花岗岩有关的离子吸附型稀土矿主要受控于母岩稀土元素丰度、气候以及地形地貌。"沟-谷-盆"地貌两侧及周缘低缓山丘和平缓山坡、山脊是有利的成矿部位。结合区域找矿成果,认为研究区稀土矿找矿潜力较大,可达超大型远景规模,在后续的找矿工作中应加强对重稀土元素钇的评价。     

Geology and mineralization of the Sanshandao supergiant gold deposit (1200 t) in the Jiaodong Peninsula,China: A review

The Jiaodong Peninsula in Shandong Province, China is the world’s third-largest gold metallogenic area, with cumulative proven gold resources exceeding 5000 t. Over the past few years, breakthroughs have been made in deep prospecting at a depth of 500–2000 m, particularly in the Sanshandao area where a huge deep gold orebody was identified. Based on previous studies and the latest prospecting progress achieved by the project team of this study, the following results are summarized. (1) 3D geological modeling results based on deep drilling core data reveal that the Sanshandao gold orefield, which was previously considered to consist of several independent deposits, is a supergiant deposit with gold resources of more than 1200 t (including 470 t under the sea area). The length of the major orebody is nearly 8 km, with a greatest depth of 2312 m below sea level and a maximum length of more than 3 km along their dip direction. (2) Thick gold orebodies in the Sanshandao gold deposit mainly occur in the specific sections of the ore-controlling fault where the fault plane changes from steeply to gently inclined, forming a stepped metallogenic model from shallow to deep level. The reason for this strong structural control on mineralization forms is that when ore-forming fluids migrated along faults, the pressure of fluids greatly fluctuated in fault sections where the fault dip angle changed. Since the solubility of gold in the ore-forming fluid is sensitive to fluid pressure, these sections along the fault plane serve as the target areas for deep prospecting. (3) Thermal uplifting-extensional structures provide thermodynamic conditions, migration pathways, and deposition spaces for gold mineralization. Meanwhile, the changes in mantle properties induced the transformation of the geochemical properties of the lower crust and magmatic rocks. This further led to the reactivation of ore-forming elements, which provided rich materials for gold mineralization. (4) It can be concluded from previous research results that the gold mineralization in the Jiaodong gold deposits occurred at about 120 Ma, which was superimposed by nonferrous metals mineralization at 118–111 Ma. The fluids were dominated by primary mantle water or magmatic water. Metamorphic water occurred in the early stage of the gold mineralization, while the fluid composition was dominated by meteoric water in the late stage. The S, Pb, and Sr isotopic compositions of the ores are similar to those of ore-hosting rocks, indicating that the ore-forming materials mainly derive from crustal materials, with the minor addition of mantle-derived materials. The gold deposits in the Jiaodong Peninsula were formed in an extensional tectonic environment during the transformation of the physical and chemical properties of the lithospheric mantle, which is different from typical orogenic gold deposits. Thus, it is proposed that they are named “Jiaodong-type” gold deposits.©2021 China Geology Editorial Office.     

地震前兆数据监视与管理系统

在北京十三陵地震台建设了一个高度集成的地震观测监控系统, 将原来分散的观测项目(如测震、 GPS、 气氡、 气汞、 电磁波、 地电场等测项), 改造为集中到一台服务器管理, 在一个监控平台上统一实现了对台站数据的收集、 入库、 管理、 处理、 监控等业务; 对这些观测项目可以在控制台上直接取数并将数据入库; 初步实现了观测数据的收集、 数据处理、 数据管理、 数据监控的软件管理系统, 减少了系统维护工作量, 方便台站工作人员操控。 监控系统的地震前兆数据监管软件系统DataMonitor可准实时监视数据, 检查数据的异常和到达情况, 并向台站数据管理人员告警; 可对数据库数据进行统计, 包括数据到达情况统计、 缺数统计、 数据连续率统计等, 并可按用户定制的测项分类进行统计。 该系统还提供多种前兆数据处理方法, 实现对前兆数据的各种常规分析处理。 地震前兆数据监视与管理系统已在北京十三陵地震台应用, 满足了数据管理人员日常工作需要, 可及时方便地掌握数据的情况并对观测系统进行维护。     

中国隧道及井巷地震波法超前探测技术研究分析

自20世纪90年代以来,反射地震波法作为一种主要的超前探测技术在我国国内隧道及井巷工程中取得了诸多成功应用的探测实例,同时在应用中不同探测方法也存在不少问题。文章结合国内外超前探测中应用较为广泛的TSP法、负视速度法、HSP法、TRT法、ISIS系统等反射波探测技术加以阐明,分析了国内超前探测技术应用与研究的现状,指出隧道及井巷超前探测数据采集与处理过程中存在的不足,并进一步提出超前探测研究在正反演理论、数据采集、偏移成像技术等方面应该注意的问题,超前探测的目标是要建立和完善一套实时的巷道前方地质体的动态监测与预报系统。     

三参数小波及其在地震资料分析中的应用

提出了一类含有三个可调参数的分析小波（称为三参数小波）,通过选择这三个参数,可使其最适合于所给定的问题．Morlet小波及改进的Morlet小波是其特例．通过对三参数小波中的参数加以约束,可以获得一类新的近似解析小波．论证了通过恰当的选择参数,三参数小波不仅适合于分析包含慢变频率和振幅分量的信号,而且也适合于包含快变分量的信号．以三参数小波为分析小波,提出了一种用于薄互层地震资料分析的方法．该方法能够刻画薄互层的沉积旋回,也能研究薄互层内部的局部结构,并采用模型资料验证了方法的有效性．