基于倾角仪与测量机器人的异形桥变形监测研究     

张海明  王明常  林楠  王凤艳  张馨月 《世界地质》2019,(2):513-521

为研究影响异形结构桥梁变形的因素,分析不同测量手段反映异形桥变形的灵敏度,以吉林省延边朝鲜族自治州安图县二道白河镇美人松空中廊桥公园内空中廊桥为例,采用倾角仪和测量机器人联合的方式,在顾及荷载、风向和风速的作用下,测定廊桥的倾斜角和位移量,获取两套独立观测数据。通过正交试验分析荷载、风向和风速对廊桥倾斜程度的影响,并通过灵敏度试验分析两种测量手段反映廊桥变形的灵敏度。研究结果表明,倾角仪和测量机器人都能较高精度地反映廊桥变形且数据相近,倾角仪反映廊桥变形灵敏度更高,廊桥变形主要受荷载和风速影响。  相似文献   

实验室与田间条件下骨炭粉与海藻肥对镉污染土壤修复效果评价     

王萌  陈世宝  李杉杉  李晓越  郑涵  孟楠 《地学前缘》2019,26(6):82-88

本研究基于小麦、玉米、高粱籽粒及烟草烟叶镉(Cd)消减率、修复边际效率及土壤中Cd有效态含量的变化等对比了实验室与田间条件下骨炭粉与海藻肥对Cd污染农田土壤的修复效果。研究结果表明：骨炭粉与海藻肥使玉米、小麦、高粱和烟草对Cd的吸收、转运均有显著(P<0.05)降低作用;在田间条件下,骨炭粉与海藻肥对不同作物籽粒或烟叶的Cd消减率为16.2%~39.8%,可增加作物产量12.3%~38.6%。钝化剂对不同作物增产效果有一定差异,对小麦籽粒增产作用最为有效。研究发现添加钝化剂改变了Cd在土壤团聚体中的分布,使得Cd在大粒径团聚体中负载量增加,并且与对照相比,显著提高土壤pH(提高0.43~0.77),降低土壤Cd的有效性,有利于控制Cd在土壤植物系统中的迁移。总体而言,不同钝化剂的Cd污染土壤修复边际效率为3.99%~14.74%,同海藻肥相比,骨炭粉的修复边际效率较高。不同钝化剂在盆栽实验的修复效果优于田间实验的效果,可能是因为相比于田间实验,盆栽实验条件下根系的作用范围有限,钝化剂的作用效果较高。  相似文献   

阳山金矿带金的赋存状态及其对成矿过程的指示意义     

李楠  邓军  张志超  刘兴武  刘基 《地学前缘》2019,26(5):84-95

阳山金矿带是西秦岭金矿带已探明金储量最大的独立金矿区,其矿化样式主要为微细浸染状矿化,其次为石英脉型矿化,可见金与“不可见金”均有发育,该金矿带是研究造山型金矿金赋存状态的理想地区,其研究成果对理解金成矿作用和过程以及指导选矿工艺具有重要意义。论文在翔实的野外地质调查和显微观察基础上,将成矿期划分为早阶段(黄铁矿石英)、主阶段(黄铁矿毒砂绢云母石英)和晚阶段(辉锑矿石英方解石),综合应用电子探针、激光剥蚀电感耦合等离子体质谱、电感耦合等离子质谱仪、高分辨率透射电镜、X射线粉晶衍射等技术,剖析阳山金矿带不同成矿阶段金的赋存状态,进而探讨其对成矿过程的指示意义。研究表明：成矿早、主阶段以微细浸染状硫化物矿化为主,金主要以晶格金的形式赋存于黄铁矿和毒砂中;而成矿晚阶段以脉状矿化为主,金主要以自然金的形式存在。金的赋存状态的变化,指示从成矿早阶段到晚阶段,成矿温度、压力逐渐降低,成矿流体成分由富As流体演化为相对贫As且富Sb的流体。  相似文献   

中国中新元古代重要沉积地质事件及其意义   总被引：2，自引：2，他引：0       下载免费PDF全文

旷红伟  柳永清  耿元生  白华青  彭楠  范正秀  宋换新  夏晓旭  王玉冲  陈骁帅 《古地理学报》2019,21(1):1-30

地球曾经历了3次超大陆演化过程,其中2次超大陆(哥伦比亚(Columbia)和罗迪尼亚(Rodinia))旋回涉及中新元古代,并与一系列区域性事件相联系,形成了多成因的超大陆演化模型。华北中东部新元古代沉积事件、扬子和塔里木新元古代裂谷事件、雪球事件等都被视为Rodinia超大陆的裂解响应,它们对定时三大陆块相互关系及定位其在全球超大陆的位置具有至关重要的作用,也反映了重要沉积地质事件在超大陆研究中不可或缺的作用和意义。此外,在中新元古代的Columbia和Rodinia超大陆演化过程中,还伴随发育具有广泛区域性甚至全球意义的巨厚白云岩与碳酸盐岩微生物(岩)、红层与黑色页岩、全球性臼齿亮晶碳酸盐岩和埃迪卡拉纪盖帽碳酸盐岩等沉积事件群及元素(同位素)漂移等地球化学异常事件,也包括特殊且重要的磷块岩、锰、铁矿等沉积成矿事件。由于不断显示出来在全球古大陆重建和古地理恢复方面的重要作用,它们越来越得到学术界的广泛关注和研究。文中通过系统分析中国中新元古代超大陆旋回演化中发育的部分重要或关键地质事件(群)时空发育与分布特征,并结合作者团队的实际资料和测试数据,以期揭示超大陆演化过程与重要沉积地质事件的内在联系,为超大陆聚散旋回演化和时空定位及原型沉积盆地的发育和评价提供科学证据。  相似文献   

Improving a thermal conductivity model of unsaturated soils based on multivariate distribution analysis     

Zou  Haifeng  Zhang  Nan  Puppala  Anand J. 《Acta Geotechnica》2019,14(6):2007-2029

Soil thermal conductivity (k) is a key parameter for the design of energy geo-structures, and it depends on many soil properties such as saturation degree, porosity, mineralogical composition, soil type and others. Capturing these diversified influencing factors in a soil thermal conductivity model is a challenging task for engineers due to the nonlinear dependencies. In this study, a multivariate distribution approach was utilized to improve an existing soil thermal conductivity model, Cote and Konrad model, by quantitatively considering the impacts of dry density (ρ_d), porosity (n), saturation degree (S_r), quartz content (m_q), sand content (m_s) and clay content (m_c) on thermal conductivity of unsaturated soils. A large database containing these seven soil parameters was compiled from the literature to support the multivariate analysis. Simplified bivariate and multivariate correlations for improving the Cote and Konrad model were derived analytically and numerically to consider different influencing factors. By incorporating these simplified correlations, the predicted k values were more concentrated around the measured values with the coefficient of determination (R²) increased from 0.83 to 0.95. It is concluded that the developed correlations with the information of different soil properties provide an efficient, rational and simple way to predict soil thermal conductivity more accurately. Moreover, the quartz content is a more important factor than the porosity that shall be considered in the establishment of thermal conductivity models for unsaturated soils with high quartz content.

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Analysis of hydrogeolgical characteristics and water environmental impact pathway of typical shale gas exploration and development zones in Sichuan Basin,China     

SUN Dong  LIU Xin-ze  YANG Hai-jun  CAO Nan  ZHANG Zhi-peng  CHEN Yin-song  LI Da-meng 《地下水科学与工程》2019,7(3):195-213

Studying the influence of shale gas exploration and development on groundwater environment is the basis of guiding water environment protection in the process of shale gas exploration and development.Groundwater environmental pollution is concealed,complex and persistent.Once it is difficult to control the pollution,the current commercial shale gas development zones in Sichuan Basin that are mostly located in karst areas and highly sensitive to groundwater will be vulnerable to the impact of shale gas exploration and development.Based on the hydrogeological conditions of shale gas exploration and development area and combined with engineering analysis of exploration and development,various risk pathways that may affect the groundwater environment during process of shale gas exploration,mining well construction,mining operations and other stages were identified in this paper.Some existing risk pathways were proved by verification of typical areas and should not be ignored.Based on the actual situation of typical areas,the countermeasures of groundwater environmental protection in the process of shale gas exploration and development in karst areas were discussed.It is believed that the groundwater environment can be better protected by strengthening administration,research and application of new technologies,precise design,hydrogeological conditions,and research and feedback of groundwater environmental protection.  相似文献   

贵州广顺二叠系化学地层的划分及沉积环境分析   总被引：2，自引：2，他引：2  

南君亚  周德全 《矿物学报》1996,16(2):223-230

本文以贵州省广顺二叠纪坝子头－茶叶剖面作了基准剖面，通过野外观察和室内岩相分析，根据岩石的成岩作用，颜色，微相特征及岩层的厚度和叠置关系，进行了层序的划分。在此基础上，以该剖面５９个岩层的１７个微量元素（Ａｓ，Ｂ，Ｂａ，Ｃｏ，Ｃｒ，Ｃｕ，Ｇａ，Ｍｎ，Ｍｏ，Ｎｉ，Ｐｂ，Ｓｎ，Ｓｒ，Ｔｉ，Ｖ，Ｚｎ和Ｚｒ）为变量，用因子分析和群分析进行了化学地层单元的划分，通过化学地层和层序地层划分结果的对比，结合化学  相似文献   

Tropical Storm and Hurricane wind effects on water level, salinity, and sediment transport in the river-influenced Atchafalaya-Vermilion Bay System, Louisiana, USA   总被引：1，自引：0，他引：1  

Nan D. Walker 《Estuaries and Coasts》2001,24(4):498-508

Changes in circulation, water level, salinity, suspended sediments, and sediment flux resulted from Tropical Storm Frances and Hurricane Georges in the Vermilion-Atchafalaya Bay region during September 1998. Tropical Storm Frances made landfall near Port Aransas, Texas, 400 km west of the study area, and yet the strong and long-lived southeasterly winds resulted in the highest water levels and salinity values of the year at one station in West Cote Blanche Bay. Water levels were abnormally high across this coastal bay system, although salinity impacts varied spatially. Over 24 h, salinity increased from 5 to 20 psu at Site 1 on the east side of West Cote Blanche Bay. Abnormally high salinities were recorded in Atchafalaya Bay but not at stations in Vermilion Bay. On September 28, 1998, Hurricane Georges made landfall near Biloxi, Mississippi, 240 km east of the study area. On the west side of the storm, wind stress was from the north and maximum winds locally reached 14 m s⁻¹. The wind forcing and physical responses of the bay system were analogous to those experienced during a winter cold-front passage. During the strong, north wind stress period, coastal water levels fell, salinity decreased, and sediment-laden bay water was transported onto the inner shelf. As the north wind stress subsided, a pulse of relatively saline water entered Vermilion Bay through Southwest Pass increasing salinity from 5 to 20 psu over a 24-h period. National Oceanic and Atmospheric Administration (NOAA)-14 reflectance imagery revealed the regional impacts of wind-wave resuspension and the bay-shelf exchange of waters. During both storm events, suspended solid concentrations increased by an order of magnitude from 75 to over 750 mg l⁻¹. The measurements demonstrated that even remote storm systems can have marked impacts on the physical processes that affect ecological processes in shallow coastal bay systems.  相似文献   

Isotopic Stratification and Its Implications in Groundwater of Northern China     

Chen Zongyu Institute of Hydrogeology  Environmental Geology  Chinese Academy of Geological Sciences  Shijiazhuang  College of Earth Sciences  Jilin University  Changchun Zhang Guanghui Ni Zhenlong Qi Jixiang Nan Yunju Institute of Hy 《中国地质大学学报(英文版)》2001,12(3)

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湖泊数据库数据结构详析   总被引：2，自引：0，他引：2  

江南  严晓蓉 《湖泊科学》1996,8(4):373-377

湖泊数据库为湖泊科学定量化研究、宏观决策分析提供了丰富的基础数据。对于如何提取数据库信息，为应用目的服务，必须了解湖泊数据库数据结构。本文概略地描述了湖泊数据信息种类，分析了湖泊空间信息和非空间信息的数据结构，尤其对关系数据库数据文件作了详细剖析，给出了调用数据文件的Ｃ语言源程序。  相似文献