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青藏直流线路冻土地基监测研究 总被引:3,自引:2,他引:1
青藏交直流联网工程是继青藏公路、 青藏铁路等之后, 在青藏高原多年冻土区建设的另一种新结构的冻土工程. 系统地分析了青藏直流线冻土工程与其它工程的差异, 并就该工程冻土基础温度、 水分、 应力和应变监测系统的建立和观测要素, 以及初步观测结果等问题进行了讨论. 通过对2011年全年观测数据分析发现, 整个监测系统可以准确、 及时反映输电线路冻土基础的不同性状和特征, 可以反映影响塔基稳定性的主要因素及其变化趋势. 初步观测结果表明, 在不同时段, 监测塔式基础底部总体处于冻结状态、 塔基基本稳定, 但个别监测塔基地温增温幅度、 上限融化深度较大, 沉降变形呈现增加趋势. 鉴于工程完工和荷载作用的时效性, 塔基稳定性应处于动态变化过程之中. 为正确评价塔基稳定性, 需要对塔基回填土的冻融、 水热变化和塔基变形等重要过程进行长期监测研究. 相似文献
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Test method and experimental research on resistance of oil shale under high temperature 总被引:1,自引:0,他引:1
《世界地质(英文版)》2012,(3):245-251
Heating the oil shale by current underground to accomplish in-situ transformation process, is a viable direction. The electrical properties of oil shale under different temperatures, especially the resistance, become important. Charging oil shale underground to heat oil shale till kerogen’s decomposition temperature, then crude oil and other gases can be generated. The resistance of the oil shale samples was measured by Direct Current (DC) quadripole method to find out the variation rules of resistance value. In the experiments, oil shale presented its semiconductor property. When heated till 350℃-450℃, its resistance changed greatly, optional for heating and cracking. The porosity, oil content, media and composition affected the resistance largely. 相似文献
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《Urban geography》2013,34(4):297-329
This paper examines recent proposals for memorials and monuments on the National Mall in Washington, DC. Demands for memorials are increasingly at odds with the Mall's important role as open green space and public protest space. This article analyzes the broader issues embodied in the competing purposes of this highly visible public space by considering the recent controversy over the World War II Memorial. The controversy focused primarily on the location of the memorial. Opponents contended the World War II Memorial would interrupt or destroy the iconography of the National Mall. Supporters argued that the location selected for the memorial was consistent with its importance in U.S. history and that it deserved such a prized location in the central axis between the Lincoln Memorial and the Washington Monument. The article then analyzes the politics behind the site selection, and examines the debate about the impact of the memorial's location. It concludes that the location of the memorial was not accidental but intentional, and thereby reveals a purposeful re-writing of the Mall's symbolic space to suit a specific vision of the war and its meaning in American history. The article also contends that the location of the memorial represents an emerging social-political agenda that is prioritizing the Mall as a place of commemoration at the expense of open space, and, perhaps, at the expense of public protest space. 相似文献
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The diapiric province of north-eastern Algeria and Tunisia extends NE–SW over several hundreds of kilometres. Available, geophysical and geological investigations were focused on the study of known diapiric outcrop. In contrast to the existing work, our study is focused on to identify a new hidden near surface salt diapir in the Guelma Basin, north-east of Algeria.Integrated geophysical study comprising aeromagnetic, gravimetric and DC resistivity data calibrated with existing well information provides new insights into the geometry of the geologic structure of Guelma Basin. Spatial correlation between magnetic low, strong gravity minimum and resistivity high reveal a hidden near surface salt diapir. The Guelma salt diapir is topped by a local topographic high which follows exactly the underlying salt body. Joint gravity-magnetic modelling indicates that salt is deeply rooted and has a dome-like shape. The Guelma salt diapir was triggered by normal faulting and is directly controlled by regional extension. 相似文献