高密度电法在某地铁工程孤石勘察中的应用

高密度电法具有勘探精度高,信息量大等优点,它已成为工程勘察中的主要物探手段之一。在地铁工程建设中常因地下孤石而导致盾构施工困难、耽误工期。该文通过工程实例,介绍了高密度电法在东莞R2线地铁工程孤石勘察中的应用效果,分析了不同装置形式下的探测效果以及在沥青路面实施探测的方法和数据解释。实例分析表明,高密度电法在孤石勘察中具有较好的效果。该文为孤石勘察工程提供了有益的参考。     

广州地区疑难地层中土压平衡盾构推进技术措施浅谈

广州地铁土建工程大量采用盾构工法,但当地复杂的地理地质条件使得该工法在应用中面临诸多难题,文章简要分析了在广州市各种疑难地层中盾构推进的困难之处以及相关的技术措施,即在上软下硬地层中、砂层和孤石区及长距离硬岩段盾构推进技术措施。     

广州地区疑难地层中土压平衡盾构推进技术措施浅谈

广州地铁土建工程大量采用盾构工法,但当地复杂的地理地质条件使得该工法在应用中面临诸多难题,文章简要分析了在广州市各种疑难地层中盾构推进的困难之处以及相关的技术措施,即在上软下硬地层中、砂层和孤石区及长距离硬岩段盾构推进技术措施。     

国内首条长距离大断面海底盾构隧洞掘进施工关键技术

台山核电站1#、2#取水隧洞是国内首条长距离大断面海底盾构隧洞工程,通过不断摸索和实践,成功地解决了盾构机选型、盾构始发、海底孤石预处理等几项关键技术和施工屏障,这些施工经验为今后的类似工程提供了借鉴和指导作用.     

地铁隧道盾构下穿施工地块的数值分析

以佛山某地铁工程为例,分析盾构隧道开挖与上部地面结构同步施工的相互影响。采用Midas GTS NX软件建立三维有限元模型,对比上部结构在正常施工与停止施工的2种工况下盾构隧道开挖过程中的位移状况。结果表明:在"桩基础+托换梁"的条件下,上部结构施工对下穿隧道的盾构开挖有一定影响,但影响较小,两者同步进行施工基本可行。     

排列方式及电极距对高密度电法探测孤石的影响分析

通过高密度电法在广州某地铁线路勘察孤石的探测试验,分析几种不同排列方式及电极距对孤石高密度电法探测效果的影响,同电极距时,偶极装置具较高精度,对浅部不均匀体反映也较灵敏。满足探测深度条件下,缩小电极距时,微分装置相比偶极和温纳装置其探测精度效果更明显。试验表明β和γ装置测量数据的T比值参数法具有较好的探测效果,在实际工作中值得进一步试验推广。     

软土夹砂地区近距离桩基施工对地铁盾构隧道的影响及治理

该文以南京河西软土夹砂层地区某桥梁工程桩基施工近距离地铁盾构隧道为例,介绍了试验桩及内插桩施工期间对盾构隧道沉降的影响程度,并对该过程进行了研究分析,总结出跳桩施工、连续穿透、及时注浆、自动化监控等有益方法,可为后续类似工程提供一定的经验。     

地铁盾构下穿既有火车站施工风险控制分析

以地铁盾构穿越既有火车站为工程背景,分析了盾构下穿火车站、小半径曲线盾构施工的风险及其控制措施。     

微扰动注浆对地铁隧道收敛变化的研究

城市盾构隧道多建在建筑物高度集中地区,周边建筑的施工往往会对盾构隧道造成一定的影响。该文以天津某运营的地铁盾构隧道为背景,探讨了微扰动注浆施工引起的侧向挤压力对地铁盾构隧道的收敛影响,并对微扰动注浆施工技术参数、施工方法、监测手段等方面进行了简要的说明,重点分析了不同情况下注浆对盾构隧道收敛的影响。     

盾构隧道管片与道床的稳定加固处理

处理淤泥质地基的上海地铁盾构隧道 ,经过四年的运行 ,淤泥地基出现变形 ,使盾构隧道产生不均匀沉降 ,导致地铁道床与管片剥离开裂 ,部分位置出现渗漏水和冒泥 ,为确保地铁正常运行 ,该文介绍采用复注浆法处理盾构隧道管片与道床的稳定与加固方法。     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586