Access routes to high mountain huts facing climate-induced environmental changes and adaptive strategies in the Western Alps since the 1990s     

Jacques Mourey  Ludovic Ravanel  Christophe Lambiel  Joël Strecker  Mattia Piccardi 《Norsk geografisk tidsskrift. Norwegian journal of geography》2019,73(4):215-228

ABSTRACT

In the European Alps, high mountain environments are subject to major impacts resulting from climate change, which strongly affect human activities such as mountaineering. The purpose of the study was to examine changes in access routes to 30 high mountain huts in the Western Alps since the 1990s. Data were derived from the use of two different methods, geo-historical studies and a questionnaire, and were used to identify both the climate-related processes affecting the climbing routes and the strategies implemented by public entities, Alpine clubs, guide companies, and hut keepers to maintain acceptable safety and technical conditions. The case studies revealed issues affecting three access routes and the results from the questionnaire showed that the main processes affecting access routes were loss of ice thickness and retreat from the front of the glaciated areas. Commonly, in situ equipment was installed to facilitate access for mountaineers and/or a part of a route was relocated to a safer area. The authors conclude that in most cases, the measures were effective but they were limited by financial, ethical and legal issues, especially in protected or classified areas that could jeopardise their durability and effectiveness.  相似文献   

Development of detachable replaceable links for eccentrically braced frames     

Mehmet Bakır Bozkurt  Sina Kazemzadeh Azad  Cem Topkaya 《地震工程与结构动力学》2019,48(10):1134-1155

Eccentrically braced frames (EBFs) can be repaired after a major earthquake by replacing the links. The link replacement is not a straightforward process and is influenced by the type of the link and the amount of residual frame deformations. The past decade has witnessed the development of different types of replaceable links such as end-plated links, web connected links, bolted flange and web spliced links, and collector beam and brace spliced links. All of the developed replaceable link details, except the web connected links, are not suitable for link replacement under residual frame drift. In this paper, a detachable replaceable link detail which is based on splicing the link at its mid-length is proposed. The detail is well suited for installation under residual frame drifts. In addition, the weight and size of the members to be transported and erected are reduced significantly, thereby facilitating the replacement procedure. Performance of this proposed replaceable link is studied by conducting six nearly full scale EBF tests under quasi-static cyclic loading. The link length ratio, type of end-plated mid-splice connection, and the amount of residual drift are considered as test variables. The test results revealed that the inelastic rotation capacity of the detachable replaceable links exceeds the requirements of the AISC Seismic Provisions for Structural Steel Buildings. No failures are observed in the end-plated mid-splice connections demonstrating the potential of the proposed details. The detachable replaceable links are investigated by numerical analysis as well to further validate their applicability and to develop design recommendations.  相似文献   

基于水化学特征的“奥灰”地热流体水文地球化学演化机制研究——以济南东部章宁1地热井为例          下载免费PDF全文

程洪柱  成世才  王振涛 《山东国土资源》2019,35(8)

以章宁1地热井的研究为例,在分析地热水水文地球化学特征基础上,对地热水的化学成分形成进行了研究,并通过与相对补给径流区的西曹范、章桃1地下水水化学特征的比较,研究其演化机理。综合分析认为地热水为沉积岩溶滤水,属于中度变质水,地下水流经火成岩侵入体时溶解了大量的Cl~-及F~-,HSiO~-_3等微量元素,次为地下水与沿文祖断裂上升的深部热液的混合,导致地热水化学类型的改变。深部热液的水化学成分与济南东地热水与深部热液的混合比例有待进一步研究。  相似文献   

Revisiting the morphological method in two-dimensions to quantify bed-material transport in braided rivers     

Gilles Antoniazza  Maarten Bakker  Stuart N. Lane 《地球表面变化过程与地形》2019,44(11):2251-2267

Research in the 1990s showed that bed-material transport rates could be estimated at the reach scale in both one-dimension and, over small spatial scales (10s of m), in two-dimensions. The limit on the latter was the spatial scale over which it was possible to obtain distributed data on morphological change. Here, we revisit the morphological method given progress in both topographical data acquisition and hydraulic modelling. The bed-material transport needed to conserve mass is calculated in both one and two dimensions for a 1600 m × 300 m Alpine braided river “laboratory”. High-resolution topographical data were acquired by laser scanning to quantify Digital Elevation Models (DEMs), and morphological changes caused by the flushing of the water intake were derived from repeated surveys. Based on DEMs of differences, 1D bed-material transport rates were calculated using the morphological method. Then, a 2D hydraulic model was combined with a topographic correction to route sediment through the network of braided channels and to obtain a spatially variable estimate of transport in both downstream and cross-stream directions. Monte Carlo simulation was applied to the routing model parameters, allowing identification of the most probable parameter values needed to minimize negative transport. The results show that within-section spatial compensation of erosion and deposition using the 1D treatment leads to substantial local errors in transport rate estimates, to a degree related to braiding intensity. Even though the 2D application showed that a large proportion of the total transport was actually concentrated into one main channel during the studied low flow event, the proportion of transport in secondary anabranches is substantial when the river starts braiding. Investigations of the effects of DEM resolution, competent flow duration and survey frequency related to ‘travelling bedload’ and sequential erosion-deposition emphasized the critical importance of careful data collection in the application of the morphological method. © 2019 John Wiley & Sons, Ltd.  相似文献   

准噶尔盆地玛湖凹陷西斜坡三叠系百口泉组扇三角洲优质储集层预测          下载免费PDF全文

桑林翔  刘军  王贵文  王苏天  李全  张云龙 《古地理学报》2020,22(6):1053-1064

针对准噶尔盆地玛湖凹陷西斜坡风南地区三叠系百口泉组扇三角洲砂岩物性空间变化大、优质储集层(孔隙度大于7.4%,渗透率大于0.05×10^-3μm²)预测难的问题,在沉积岩石学、地震沉积学以及地震反演和解释理论指导下,综合利用测井、岩心和三维地震等资料开展了高精度层序地层划分、沉积微相描述和优质储集层地震反演研究。建立了风南井区四级层序地层格架,明确了扇三角洲多期水进水退的充填过程,指出SSQ3和SSQ5是优质储集层的发育层系;识别出扇三角洲平原分流河道、河道间和扇三角洲前缘水下分流水道、河口坝、席状砂等沉积微相,指出扇三角洲平原是优质储集层发育相带;通过应用高分辨层序地层纵向边界和沉积相横向边界约束,进行分层相控叠后地震波阻抗反演,提升储集层预测精度,在SSQ3和SSQ5预测5个优质储集层发育区,提出3口井的井位建议,钻探均获工业油流。  相似文献   

川藏铁路交通廊道地质调查工程主要进展与成果     

郭长宝  王保弟  刘建康  涂杰楠  张永双  马剑飞  铁永波  韩冰  马鑫  刘峰  李雪  孟文  钟宁  杨志华  吴瑞安 《中国地质调查》2020,7(6):1-12

川藏铁路是我国正在规划建设的重点工程,由于其位于地形地貌和地质构造都极为复杂的青藏高原东部,在铁路规划建设中面临一系列迫切需要解决的关键地质问题: 区域性活动断裂与断错影响、地质灾害、高地应力及其引起的岩爆和大变形、高温热害、断裂带高压水与涌水突泥、高陡边坡稳定性等。为满足技术支撑川藏铁路规划建设、精准服务国家重大战略实施的需要,中国地质调查局部署了“川藏铁路交通廊道地质调查工程”,聚焦制约川藏铁路规划建设的关键问题,充分发挥地质调查工作对国家重大工程规划建设的支撑作用。2019年主要完成铁路沿线1:5万区域地质调查1 350 km²、1:5万地质灾害调查5 000 km²,建设6口大地热流地质参数井、8个地温监测站,完成地应力测量20孔,编制完成11份地质调查专报,提出的大渡河大桥段、理塘车站段、毛垭坝盆地段等线路优化建议/防灾建议被采纳; 首次将1:5 000大比例尺航空物探技术引入复杂山地铁路工程勘察,创新形成千米级超长水平钻孔定向取心钻进技术,实现500 m深的水平孔地应力测量突破等。该工程通过2019年调查研究,全力提升了铁路沿线地质调查程度与精度,并创新了复杂艰险山区重大工程地质问题与探测技术、地质灾害风险防控理论与减灾关键技术,有效支撑服务了川藏铁路规划建设。  相似文献   

MEEMD-Elman神经网络的电离层TEC预报模型     

汤俊  高鑫 《大地测量与地球动力学》2020,40(4):395-399

利用IGS中心提供的不同纬度的电离层TEC值,建立基于改进的集总平均经验模态分解(MEEMD)算法和Elman回归神经网络(ERNN)模型相结合的电离层TEC预报模型。实验结果表明,在低、中、高不同纬度采用本文方法预报5 d电离层TEC的预测值的均方根误差最优可达到0.96 TECu,相对精度最优达到95.4%,精度较EMD-ERNN模型及单一ERNN模型有显著提高。  相似文献   

福建北部近岸东台山岛火山岩形成时代、地球化学与古太平洋板块俯冲的响应          下载免费PDF全文

王飞飞  张勇  韩宗珠  宋维宇  吴浩  宁泽 《中国地质》2020,47(5):1426-1437

福建北部沿岸岛屿岩石组合以晚中生代火成岩为主，研究认为是古太平洋俯冲消减的产物，对反演洋盆构造演化具有重要的指示意义。本次对其中的福建北部海域东台山岛上广泛发育的酸性火山岩进行了锆石U-Pb定年以及全岩主微量地球化学分析工作。2件年代学样品分别获得了92 Ma和86 Ma的锆石U-Pb年龄，确定东台山岛火山岩形成于晚白垩世。全岩地球化学特征指示火山岩样品以酸性钙碱性岩石为主，整体富集Rb、Ba等元素，亏损Nb、Ta、Sr、Eu等元素，显示弧型岩浆岩的地球化学组成。研究认为东台山岛火山岩起源于古老下地壳变沉积岩熔融，并在浅层岩浆房内经历了不同程度的结晶分异过程。结合区域上晚中生代岩浆作用由陆向海的时空迁移特征，福建北部沿岸岛屿火山岩形成的深部动力学机制应该与古太平洋俯冲过程中的板片回转过程相关。  相似文献   

国内外割心钻具研发概况与分析          下载免费PDF全文

李鑫淼  梁健  尹浩  王志刚  梁楠 《探矿工程》2020,47(7):47-55

在松散、松软、破碎等复杂地层钻进时，与常规取心技术相比，割心技术能够获得更高的岩心采取率。国内外研发的割心钻具主要包括双动双管、单动双管和绳索取心割心钻具3种，钻具研发的关键点主要包括岩心爪结构设计和加压方式选择。从钻具研发情况看，三角形岩心爪具有良好的闭合性能，液力加压能够实现对割心压力的准确控制，绳索取心割心钻具钻进效率较高，但研发难度相对较大。本文详述了国内外割心钻具的结构设计特点及取心操作流程，分析了钻具设计原理的优缺点，提出了割心钻具发展趋势，为割心钻具的优化设计奠定了基础。  相似文献   

华南上扬子区深部温度估算及其油气地质意义     

李香兰  刘绍文  徐明  李旭东  郝春艳 《地质学报》2020,94(6):1896-1910

盆地热体制及深部温度估算对油气和区域地热能资源评估具有重要意义。南方上扬子区是海相油气勘探的重要区块,近年来更是我国页岩气勘探的主要选区。然而,由于数据不足及研究目标的分散,该区的盆地热体制特征还有待深化。结合前人已有地热数据,并整合新近开展的稳态测温数据,我们揭示了上扬子区现今地温梯度、大地热流分布特征,继而估算了1000～6000m埋深处的深部地层温度和2套主要古生界海相烃源岩底界面处的温度。结果表明,上扬子区具有中-低温的地热状态,其现今地温梯度和大地热流的范围(平均值)分别为10～74℃/km(24℃/km)和27～118mW/m~2(64mW/m~2),整体上从东北向西南方向递增,呈现出"东北低、西南高"的分布趋势。1000～6000m埋深处估算温度的分布格局与地温梯度及热流的分布趋势基本一致。东北部的鄂西-湘北地区为低温区,中部的四川盆地其大部分为中温区,西南的云南地区为高温区。上扬子区现今地热分布格局受区域差异构造和岩浆作用控制。结合储层温度估算并综合其他油气地质资料,提出川东的石柱-涪陵、川南的威远-自贡-泸州和宜宾-长宁等区的下志留统龙马溪组页岩层系是上扬子区油气勘探有利区带。  相似文献