巷道围岩支护系统粘弹性分析蠕变柔量法

以圆形巷道为例，讨论了围岩支护系统应力与变形的时间效应，建立了巷道围岩支护系统粘弹性分析的一种新方法——蠕变柔量法，得到围岩支护系统的适用于反问题的粘弹性应力解与位移解．对于反问题，巷道围岩支护系统的新的粘弹性分析方法，使有支护和无支护围岩可以依据相同的粘弹性反分析的解析方法，识别围岩的力学模型和反演力学参数．解决了粘弹性位移反分析解析方法实用化中的一个重要问题     

巷道围岩支护系统粘弹性分析蠕变柔量变

以圆形巷道为例，讨论了围岩支护系统应力与变形的时间效应，建立了巷道围岩支护系统粘弹性分析的一种新方法－蠕变柔量法，得到围岩支护系统的适用于反问题的粘弹性应力解与位移解。对于反问题，巷道围岩支护系统的新的粘弹性分析方法，使有支护和无支护围岩可以依据相同的粘弹性反分析的解析方法，识别围岩的力学模型和反演力学参数。解决了粘弹性位移反分析解析方法实用化中的一个重要问题。     

基于粘弹性理论的巷道围岩应力场、位移场解析预测

以粘弹性理论为基础,采用解析的方法,通过拉普拉斯变换,建立了考虑时效性的围岩应力场、位移场数学表达式。利用位移及应力边界条件,导出了高强预应力锚杆支护下的围岩应力场、位移场解析解。工程实践表明,随着巷道的开挖,锚喷支护能有效控制围岩稳定,且支护后围岩的应力场、位移场随时间的变化趋于稳定,理论上验证了解析解的合理性和科学性。     

基于Maxwell模型的有限元粘弹性位移分析

利用基于Maxwell模型的围岩位移的粘弹性解析解,建立了弹性模量随时间变化的关系式,并将该式应用到有限元中,得到了有限元的粘弹性位移递推公式,可以方便准确地对位移的发展做出预测。最后将该方法应用到工程实际中,计算的位移与实测位移能很好吻合,从而证明该方法是有效的。     

孔隙水压对岩体蠕变影响研究

将巷道围岩视为多孔介质,考虑地下水渗流作用的影响,应用弹性力学理论以及粘弹性蠕变力学理论,导出了巷道围岩的应力、应变、位移等的分布规律,以及它们与孔隙水压力之间的关系;找到了影响蠕变的又一主要因素———孔隙压力,建立了深部岩体非线性蠕变的力学模型和数学模型。     

孔隙水压对岩体蠕变影响研究

将巷道围岩视为多孔介质，考虑地下水渗流作用的影响，应用弹性力学理论以及粘弹性蠕变力学理论。导出了巷道围岩的应力、应变、位移等的分布规律，以及它们与孔隙水压力之间的关系；找到了影响蠕变的又一主要因素——孔隙压力，建立了深部岩体非线性蠕变的力学模型和数学模型。     

圆形巷道围岩的流变分析

圆形巷道围岩位移是表征和控制圆形洞室工作状态的重要参数;围岩失稳与岩体的流变性质密切相关,即在一定载荷下,经历一段时间后会发生延迟失稳;围岩采用西原模型材料,运用流变学的一般解法,得出围岩处于粘弹性和粘弹粘塑性两种状态下位移的解析解;通过分析可预测位移变化的动态过程,较准确地预测围岩的弹塑性及弹塑粘性位移,这为正确合理地选择衬砌参数和安设衬砌时间等提供了较为可靠的依据;同时也为进一步进行锚固隧道的位移和锚杆荷载计算,提供了基本思路和理论模型。     

软岩巷道流变破坏机理与合理支护时间的确定

根据岩石流变学原理,对软岩巷道围岩破坏机理进行定性地分析,运用Ｂｕｒｇｅｒｓ流变模型引入损伤变量,对圆形巷道粘弹性流变破坏规律进行定量的研究,提出了软岩巷道合理支护时间的确定方法。     

基于粘弹性模型的煤体冲击倾向指标的试验研究

在单轴压缩条件下,通过对煤样分级加载时蠕变特性的试验研究,分析了试验煤样的粘弹性蠕变特征,并根据煤样的粘弹性微分本构方程,提出了以煤的粘弹性蠕变柔度系数来判别煤发生破坏蠕变失稳的判据,同时给出了以此来划分冲击倾向度强弱的分级标准。     

近距离下煤层中空注浆锚索注浆前后周边剪应力作用机理

为解决近距离下煤层破碎巷道围岩难以控制的问题,基于理论分析和数值模拟研究中空注浆锚索注浆前后对破碎围岩的控制效果,即注浆前后中空注浆锚索与围岩的周边剪应力作用机理。结果表明：注浆前锚固段符合粘弹性本构模型,剪应力曲线呈现线性增加到非线性下降再到稳定的单峰值,注浆后巷道周围预应力场沿锚索形成一个渐变式的整体,使巷道围岩应力场重新分布,剪应力强度随之降低,应力曲线转变二次线性快速增加到非线性快速下降再到稳定的双峰值曲线,有效提高破碎围岩和软岩巷道的抗剪强度。     

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。