冻胀力对寒区隧道衬砌结构影响及其防治措施

冻胀力对寒区隧道衬砌结构的影响及其防治对策一直是我国寒区隧道工程科研难点与重点，是寒区隧道工程建设和运营面临的严峻挑战。分析了冻胀力产生的机制，从理论分析、数值计算和现场实测等方面讨论了冻胀力对寒区隧道衬砌结构的影响特点．总结了目前所采用的冻胀防治措施。     

黑山寺公路隧道衬砌结构的优化设计

基于传统安全系数经验法,以黑山寺公路隧道衬砌结构为依托工程,进行了隧道衬砌结构的数值模拟计算与作用效应对比,分析得出了隧道衬砌不同截面上的作用效应,并根据隧道衬砌单元安全系数和规范要求进行衬砌结构厚度比选和优化,提出了合理的衬砌结构厚度,为黑山寺公路隧道结构设计提供理论支持。     

盾构隧道衬砌结构形式和内力计算方法分析

随着城市的快速发展，城市人口增长对城市交通的压力急剧增大，世界各国都在通过修建各种城市隧道来缓解这一矛盾。盾构法是城市隧道工程的最主要施工方法。在盾构法施工设计中，衬砌管片结构的合理设计直接关系到隧道支护的安全性、耐久性和工程成本，为此，本文将对衬砌结构的内力常用计算方法进行分析。     

羊栈岭隧道维修加固方案的力学计算分析

羊栈岭隧道围岩软弱破碎，采用钢支撑进行补强加固。根据隧道的断面建立了相应的计算模型，采用荷载结构法对衬砌内的应力进行计算，并基于该计算结果对加固后隧道的稳定性进行了校核。     

公路隧道衬砌结构火灾损伤检测与评价

文章通过对公路隧道衬砌结构的火灾损害机理分析,用超声波法对隧道衬砌结构火灾损伤检测,对隧道衬砌在火灾中受火时间、衬砌的损伤层厚度及衬砌结损伤的力学性能及强度进行评价,针对隧道衬砌耐火性能提出隧道结构设计与施工的注意要点,为今后的隧道衬砌结构的防火设计提供参考。     

华蓥山隧道复合式衬砌的支护抗力评估

通过对隧道复合式衬砌的支护抗力分析，并利用结构承载力设计法分别计算了隧道围岩承载环、砂浆锚杆和混凝土喷层的承载能力，得出了公路隧道复合式衬砌结构承受的支护抗力大小。和现场实测的喷层应力值对比表明，两结果基本吻合。最后得出了具有一定工程意义的结论。     

公路隧道衬砌裂缝成因分析及数值模拟研究

对隧道衬砌开裂的原因进行了综合分析，并利用absys软件对衬砌在结构完整和出现裂缝的受力情况进行了对比。结果表明，裂缝给衬砌带来的应力变化比较显著，拱墙径向裂缝对衬砌力学性能影响很大，沿隧道纵深方向影响较小。     

隧道复合式衬砌防水层施设施工细则

隧道复合式衬砌防水层施设施工细则张民庆，吴全立，南琛，赵玉良，贾建波（洛阳隧道局科研所４７１００９）（洛阳隧道局二处４７１００９）前言复合式衬砌是新奥法施工隧道的基本结构形式。它由一次支护，二次模注混凝土以及在一次支护与二次模注混凝土之间设塑料板防水...     

膨胀性围岩隧道衬砌结构安全性评价

结合某膨胀性围岩隧道衬砌结构病害分布特征,对典型膨胀性围岩隧道衬砌结构进行了质量检测和承载力分析,并结合衬砌结构稳定性监测规律、检测结果进行结构计算,从质量缺陷、结构承载力、变形稳定性3个方面进行深入分析,最后对隧道结构安全进行了综合性评价。     

盾构双隧道衬砌结构应力与变形的数值模拟

为分析盾构双隧道施工周围土体及衬砌结构管片应力和变形规律,结合大连地铁2号线202标段盾构施工工程实例,运用ADINA软件对盾构施工过程进行动态模拟,建立了盾构隧道-混凝土衬砌结构-注浆土体-原状土体三维非线性有限元计算模型,综合考虑了上部土体的岩性分层,隧道施工间的相互影响,衬砌、注浆土体和原状土体之间共同作用,盾构施工、土体注浆及衬砌支护的动态过程。通过数值分析,研究盾构双隧道施工周围土体及衬砌管片应力和变形规律,为隧道盾构施工、衬砌管片设计与控制地表沉降提供施工建议。     

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     

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     

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     

唐口煤矿深部复杂开采工作面瓦斯分源涌出规律研究

研究工作面瓦斯涌出规律对工作面瓦斯治理有重要意义。为了得到唐口煤矿深部3号煤层复杂开采条件下工作面回采时期瓦斯涌出时空演化规律,选取6304工作面作为对象,采用实测方法研究6304工作面瓦斯涌出规律。结果表明:6304工作面瓦斯涌出量为6.534 m³/min,其中煤壁占34.27%,落煤占29.62%,采空区占36.11%;沿工作面倾向由低到高,瓦斯浓度整体为上升趋势,其中1—76号架工作面瓦斯浓度小于0.20%,76—102号架瓦斯浓度上升明显,最大为0.387%;上隅角的后部采空区是工作面的瓦斯主要涌出源,上隅角1号测点瓦斯浓度0.78%,上隅角周边3号、5号、7号、8号、9号测点瓦斯浓度平均为0.643%;周期来压时,上隅角瓦斯相对平时较高。研究为针对性的瓦斯分源监控与灾害防治提供基础。