某尾矿坝动力响应及稳定性分析

采用等效线性法对某尾矿坝现状及堆积终期坝体的动力响应及稳定性进行了分析。研究表明：尾矿坝现状坝体和1 375 m标高坝体的加速度、位移分布规律基本一致,加速度及位移响应极值出现在坝顶区域,尾矿坝堆积标高对坝体加速度和动位移影响较小;动剪应力极值出现在建基面附近,向坝坡及坝顶方向逐渐减小,随着堆积坝标高的上升,坝体剪应力极值增大;在动力作用下,尾矿库现状坝体和1 375 m标高坝体没有出现贯通性液化区域,1 375 m标高坝体动力稳定安全系数较现状坝体安全系数有所降低,但均能满足抗滑稳定要求,尾矿库扩大放矿规模后坝体整体是安全可靠的。     

寺院沟尾矿库加高扩容坝体的稳定性分析

采用总应力法对寺院沟尾矿库初期坝、堆积坝现状的稳定性进行计算复核,坝体最小抗滑稳定系数均满足要求;对尾矿堆积坝顶高达到120 m及150 m时进行了稳定性分析。在分析的基础上,提出建议:采取有效的排渗措施,加快库底尾粉质泥土固结,提高其抗剪强度指标。     

基于粗糙集与贝叶斯决策的尾矿坝浸润线预警

为支持尾矿库的现场安全监管与决策,根据粗糙集和贝叶斯决策理论,提出了基于不确定性的尾矿坝浸润线预警方法以确定合理的尾矿坝浸润线预警阈值。首先,根据尾矿渗透性与干滩长度的不确定性对坝体稳定性的影响,计算得到离散尾矿坝体安全系数对应的浸润线的多点位(埋深)数据;其次,以粗糙集属性重要度分析为前提,采用贝叶斯决策法建立坝体安全系数与浸润线埋深的多属性决策模型,以互信息熵表示安全系数对浸润线多点位埋深数据的依赖程度;最后,用条件概率量化浸润线重要点位对尾矿坝稳定性的影响,通过最大后验概率确定浸润线埋深预警阈值。通过对陕西某尾矿坝的实例研究,得出堆积坝标高1 220. 03、1 200. 03、1 180. 03、1 150. 03 m处的浸润线高于37. 33、19. 9、17. 6、11. 6 m时,尾矿坝存在潜在不稳定风险,应采取措施降低浸润线高度。结果表明,浸润线预警阈值能客观反映尾矿坝稳定性状况,完善了尾矿库的现场监测预警体系。     

大型尾矿坝加高过程三维渗流分析

采用三维有限元渗流和稳定性分析相结合的方法,对大型尾矿坝加高过程进行稳定性评价。分析结果表明:现状坝体的浸润线高度和渗流路线正常,稳定性系数满足要求,但安全储备量不大;加高坝体时浸润线高度变动不大,排渗设施对降低浸润线有重要作用。当坝高加高到100m坝高时,坝坡抗滑稳定安全系数稍小于规范值,继续增加坝高导致坝坡抗滑稳定系数与规定值差距较大,不满足规范要求。通过数值计算确定了尾矿坝加高限值为100m,并给出填筑过程的建议措施。     

御驾泉尾矿坝稳定性计算与分析

在查明御驾泉尾矿坝工程地质条件的基础上,采用极限平衡法和快速拉格朗日法计算了坝体标高334 m时在正常运行、洪水运行和特殊运行工况下的稳定系数。结果表明坝体是安全的,但是在特殊运行（地震条件）工况下的稳定系数并不高,仅为1.06,所以需要注意防范尾矿坝在特殊运行工况下发生坝体失稳事件。     

上游法尾矿坝加高扩容的加固处理措施

介绍了上游法尾矿充填筑坝，主要是通过坝顶均匀分散排矿，在重力分选作用下粗颗粒堆积于坝顶形成尾矿子坝，细颗粒则排向库内，形成尾矿沉积滩，该法尾矿坝由于缺乏防渗条件，加上坝顶排矿水的影响，坝体浸润线位置较高影响坝体稳定，为确保在加高扩容过程中，初期土石坝和后期坝安全稳定性所采取的加固处理措施。     

高地震烈度下宽顶废石尾矿坝的动力响应分析

云南某尾矿库设计将排土场修整后作为尾矿坝,形成的宽顶废石坝最大坝高182m,坝顶宽度496m,尾矿坝处于8度地震烈度区。采用等效线性黏—弹性模型,对宽顶废石尾矿坝的动力响应进行分析,得出高地震烈度条件下坝体加速度、动应力及动力稳定性。研究结果对高地震烈度区尾矿坝工程建设具有指导意义。     

高尾矿堆积坝动力稳定计算分析

高尾矿堆积坝的坝体稳定问题尤其是动力稳定问题越来越受到行业和监管部门的重视,并取得一定发展。以正在运行的某200 m高尾矿坝为例,运用Geo-Studio软件的Quake模块建立高尾矿堆积坝的动力反应计算分析有限元模型,对坝体进行动力稳定性模拟分析。在静力有限元计算结果的基础上,计算随时程变化的坝体最小安全系数以及坝体永久变形,确定了地震波作用下的尾矿坝液化区域,提出了提高尾矿坝抗震液化的相关建议,为确保尾矿坝的安全运行提供了理论依据,可作为类似工程的参考。     

地震作用下高尾矿坝三维有限元动力分析

为分析解决高尾矿坝的抗震稳定性问题,采用三维有效应力动力分析法,以河南洛阳某拟建高尾矿坝为例,分析该坝的动力响应、地震液化区域及干滩长度变化,评价其动力安全稳定性。计算结果表明:动加速度、有效应力、动位移从坝基到坝顶、从坝内到坝坡逐渐增大,最大值一般位于初期坝顶或堆积坝顶部;地震永久沉降约为坝高的0.06%,考虑永久沉降后,坝顶安全超高、干滩长度仍满足规范允许要求;堆积坝上游浸润线以下部分出现小范围地震液化区域,但对坝体安全基本无影响。     

基于渗流与应力耦合的尾矿坝稳定性分析

针对尾矿库坝体加高影响其稳定性的问题,基于有限差分法采用渗流与应力耦合模型,对某尾矿坝在4种不同工况下进行渗流场和静力场分析。渗流场计算结果表明:加高坝体在洪水位工况下,坝体内自由面比现状坝洪水位工况升高很多,浸润线最小埋深为5.88 m,小于规范规定的最小埋置深度6~8m,加高坝体在洪水位工况是不安全的,需采取加固措施。应力场计算结果表明:加高坝体洪水位工况下,初期坝坝脚外坡处应力水平值为0.8,坝坡靠近堆积坝坝顶处应力水平值为0.75,应力水平过大,需采取加固和排渗措施,分析结果与渗流场分析结果一致。     

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