乌东德水电站拱坝坝基岩体松弛特征研究

高拱坝巨大荷载直接面对的是坝基表层卸荷松弛岩体,研究坝基卸荷后松弛岩体的特征,合理评价其影响并提出处理建议是拱坝建设中的关键。基于乌东德坝基工程地质条件,在详细调查建基面的基础上,综合利用高清电视、单孔声波测试等方法,深入研究乌东德水电站坝基岩体开挖后岩体卸荷变形特征、卸荷松弛深度、卸荷松弛程度及卸荷松弛时间效应等特征。基于坝基岩体的卸荷松弛特征及卸荷作用的时间、空间分布规律,认为乌东德坝基岩体卸荷松弛主要为开挖卸载后低地应力条件下的回弹所致,主要表现为沿已有结构面的张开,松弛深度及松弛度在一定时间后趋于稳定,不影响边坡整体稳定性,且表层卸荷松弛岩体具有较好的可灌性和灌浆效果,不需二次清挖即可满足大坝建基岩体质量要求。     

自由式单孔多锚头防腐型预应力锚索在地下厂房的运用

锦屏一级水电站地下厂房一层开挖完成后出现地应力超高,喷护混凝土脱落,岩体变形量大等不利厂房稳定因素.为了防止岩体的不利变化危害厂房的整体安全,设计起用了预应力锚索进行加强支护.主要介绍了锦屏一级电站地下厂房自由式单孔多锚头防腐型预应力锚索的施工工艺及质量控制措施.     

钢锚墩在锦屏一级水电站地下厂房的运用

锦屏一级水电站地下厂房地应力高,分层开挖完成后随着地应力的释放及重新分布,局部岩体出现压碎、层状劈裂破坏,围岩松弛深度及变位不断加深、加大。为了尽快实现锚索锚固支护效应以确保地下厂房洞室群围岩稳定和工程安全,施工时将部分原设计现浇混凝土锚墩调整为钢锚墩进行施工,取得了较好的质量、进度效果。主要介绍了钢锚墩的施工工艺、质量控制要点及其与混凝土锚墩的工效对比分析。     

基于双指标深部高应力岩体完整性的评价研究

地下岩体结构工程稳定性是地下工程的研究热点,而其中岩体完整性对地下岩体结构变形、失稳起着决定性作用,同时也是为地下工程的开挖设计、制定支护策略提供理论依据。针对会泽铅锌矿深部高应力、多地层交错等复杂地质环境,采用钻孔RQD统计法与现场声波测试技术,综合对会泽铅锌矿1274m水平岩体进行完整性评价。研究结果表明：统计的RQD均值在25.1%~29.8%之间,结合非连续面条数统计,表现岩体完整性整体上较差；声波测试显示岩体完整性系数范围在0.29~0.53之间,属于破碎及较破碎岩体。两种评价方法的实际应用,可互相评价结果的准确程度,对钻孔所揭露的岩体完整性进行定量分析,为矿山设计提供依据,可为类似矿山提供借鉴。     

锦屏二级水电站地下厂房围岩稳定分析

锦屏二级水电站地下厂房是典型的大跨度、高边墙地下洞室群,工程区地质条件较复杂,节理发育,断层较多,高边墙及洞室间岩柱的稳定性是洞室设计的关键.采用FLAC3D软件对洞室群进行了数值开挖模拟,获得了洞周围岩变形特征及应力分布状态,为洞室设计提供了科学依据与技术指导.     

锦屏一级电站尾水调压室大角度上仰孔锚索施工

锦屏一级水电站地下厂房尾水调压室顶拱发育有f14、f18断层及煌斑岩脉,开挖后出露断层及其影响带岩体破碎,风化强烈,围岩不稳定,为了洞室稳定及施工安全,设计采用预应力锚索进行加强支护.介绍了尾水调压室大角度上仰孔锚索的施工方法.     

高压压水试验在抽水蓄能电站勘察中的应用

为了确定岩体在不同压力作用下渗透特性的变化规律,陕西镇安抽水蓄能电站高压岔管、厂房端墙部位的岩体,专门做了钻孔高压压水试验。通过试验,取得了高压水头条件下岩体的透水性及透水规律,为设计在岔管和地下厂房洞室围岩稳定性、渗透性,制定厂房开挖支护措施和防渗措施,提供可靠依据。     

深井巷道围岩体声波特性及其规律

为掌握深井巷道松动圈的范围及松动圈内岩石破损程度的变化规律,对云南会泽铅锌矿950 m深井巷道进行现场声波测试。测试结果表明：不同的岩性,具有不同的声波特性,在松动圈范围内,岩体声波特性变化趋势一致;与上部测试结果相比较,松动圈的范围明显增加。在7种不同岩性的巷道围岩中,布置了10个测孔,应用单孔法进行声波测试,并对测试结果进行拟合,获得了深井巷道围岩松动圈范围内声波速度变化规律的数学表达式。为深部岩体的声波特性研究提供可靠的参考依据。     

大型地下洞室围岩稳定的三维有限元分析

使用三维有限元数值分析方法,研究了某大型水电工程大跨度、高边墙地下厂房围岩应力场的分布规律,预测了开挖后围岩破坏区的分布范围及最大变形量,评价了厂房的围岩稳定性。     

基于声波钻孔测试技术的岩体完整性分析

岩体完整性对井下岩体变形及巷道失稳破坏起着重要作用,其准确分析对开采设计、支护治理具有重要意义。针对井下矿山的特点,利用声波钻孔测试技术对现场钻孔进行声波测试,与室内实验室岩石的声波测试结果对比,对某铁矿的岩体完整性做出评价。研究表明:声波钻孔测试技术实际应用效果良好,可以对钻孔所揭露的岩体完整性进行定量分析,其声波测试结果较为准确的确定了研究范围内的岩体完整性系数,为矿山设计提供依据,可为类似矿山提供借鉴。     

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