节理岩体强度的统计描述

岩体中存在大量节理、裂隙，其分布杂乱无章，节理分布的复杂特征可以借助分形方法来描述。本文基于岩体节理断裂扩展和剪切滑移两种失稳破坏机制，运用统计断裂力学方法建立了两种破坏方式下节理岩体强度的理论表达式。结果表明，岩体强度强相关于岩体中节理分布的分形维数，分维增大导致岩体强度非线性降低。本文研究表明，分形和统计断裂力学相结合，为建立节理岩体强度与其内部结构缺陷之间的联系提供了新途径。     

节理岩体强度的统计描述

岩体中存在大量节理、裂隙 ,其分布杂乱无章 ,节理分布的复杂特征可以借助分形方法来描述。本文基于岩体节理断裂扩展和剪切滑移两种失稳破坏机制 ,运用统计断裂力学方法建立了两种破坏方式下节理岩体强度的理论表达式。结果表明 ,岩体强度强相关于岩体中节理分布的分形维数 ,分维增大导致岩体强度非线性降低。本文研究表明 ,分形和统计断裂力学相结合 ,为建立节理岩体强度与其内部结构缺陷之间的联系提供了新途径     

单一节理岩体R—R破坏准则及参数确定

为评价岩体中节理对岩体强度特性的影响，分析了单一节理的分布性状，介绍了单一节理岩体破坏的Ｒａｏ－Ｒａｍａｍｕｒｔｈｙ准则及其参数试验确定方法，并应用于峨口铁矿采场边坡两种典型的单一节理岩体强度的研究。     

节理岩体边坡采动损伤与可靠性分析

为定量分析节理岩体边坡的采动损伤对边坡可靠性的影响,通过对大孤山铁矿下盘混合岩边坡进行现场勘测与模糊C均值聚类优化分析,确定了岩体2组优势节理的倾向、倾角、迹长和密度的随机分布参数。利用Hoek-Brown强度准则参数m和s与岩体质量分类指标GSI和扰动系数的关系,采用Monte-Carlo模拟抽样技术获得了节理岩体强度的随机分布参数。建立了节理岩体损伤与扰动系数D的联系,应用Kawarnoto损伤张量对采动损伤进行了数值分析,并根据Rosenblueth原理获得了扰动系数D以及反映时空效应和各向异性的岩体强度随机分布参数。基于此,定量分析了大孤山铁矿下盘混合岩节理岩体边坡采动损伤的时空变化特征及其对边坡稳定性的影响。结果表明,采场底标高从-87 m降至最终-450 m时,坡顶至-87 m水平同一高度滑弧可靠性指标相对下降7.7%,原因为采场下移导致节理岩体损伤加剧、强度降低所致,并且危险滑面逐渐向坡面偏移,与坡面近处岩体的损伤较大相关。     

含两组交叉节理砂岩强度及破坏特征离散元分析

为研究含两组交叉节理岩体强度及破坏特征,采用一组经室内试验标定的砂岩细观参数,建立含两组交叉节理岩体颗粒流模型,进行单轴压缩和三轴压缩模拟。基于模拟结果,分析了节理数量、节理倾角和围压对含两组交叉节理岩体强度及破坏特征的影响。结果表明：① 与完整岩石相比,节理岩体强度明显降低。峰值强度随着节理数量的增加近似线性减小,随着节理倾角的增大呈先减小后增大非线性变化趋势,而随着围压的增大而提高;② 节理岩体表现为张性破坏、沿节理滑移破坏、穿节理剪切破坏、张性滑移破坏及剪切滑移破坏等5种破裂模式;③ 节理数量增加会加剧试样破坏程度,但不改变其破裂模式。单轴压缩下,当节理倾角较小时主要发生张性破坏,随着倾角的增大,表现为张性剪切或沿节理面滑移破坏。在围压作用下,试样表现为剪切破坏或剪切滑移破坏。最后从细观层面探讨了节理岩体宏观裂纹的细观位移场分布特征。     

节理网络模拟研究及其初步应用

本文针对节理岩体进行了二维与三维节理网络模拟研究。基于随机节理网络系统的连通性分析,得出了复杂连通节理网络系统的岩体等效渗透系数的一般表达式。同时,利用三维节理网络模拟,建立了包含随机非贯穿节理的节理网络系统的岩体本构关系,并分析了影响岩体弹性变形性状的因素。     

节理岩体强度及其破坏机制研究

从岩石材料的细观尺度分析节理岩体的强度特性及其变形破坏机制,细观模拟了节理岩体岩桥断裂扩展机制,进一步研究了节理岩体强度及其破坏机制。分别对含单结构面、两组结构面和断续节理岩体破坏机制进行了研究,指出大量岩体工程的失稳破坏,通常是由于开挖面附近荷载的变化,岩体中断续节理的张开、闭合和扩展而产生新的贯通滑移面引起的,即岩桥的贯通。     

节理岩体爆破的块度计算模型

以分形理论和现场实测数据为基础，提出了节理间距的Ｃａｎｔｏｒ集分布和岩体天然块度的计算方法，用随机分形构造模型描述爆破岩块的形成过程，按照损伤力学的方法，研究节理岩体爆破机制，提出岩体破碎比比率这一新概念，由此建立了节理岩体爆破块度计算的损伤模型。     

岩石粗糙节理剪切强度的分形分析

以分形维数定量描述岩石节理面粗糙性，通过剪切实验分析研究节理剪切强度、法向应力和节理面分维的相互关系，建立了能够体现节理粗糙性和节理剪胀效应的节理剪切强度表达式，提出了适用于粗糙节理岩体的库仑强度的修正公式，为更深入、更准确地研究岩石节理剪切强度和岩体结构稳定性提供了新的方法。     

含贯通-非贯通交叉节理岩体等效弹性模型及强度特性

基于等效弹性模型的方法,构建综合考虑含贯通-非贯通交叉节理岩体宏细观缺陷的复合损伤模型。首先,将贯通节理部分看成一定厚度的独立材料,其主要产生闭合变形及沿节理面的剪切变形,其储存弹性应变能及剪切应变能;其次,基于断裂力学及应变能理论相结合,将交叉节理中的非贯通节理岩体部分看成岩体内部宏观损伤,对节理尖端的应力强度因子进行了计算,推导得出了储存在非贯通节理中的应变能计算公式,并将岩体内部的细观损伤按Weibull分布描述,建立综合考虑宏细观缺陷的节理岩体复合损伤模型;再次,对交叉节理岩体的强度准则进行了讨论,构建考虑交叉节理不同强度准则的等效弹性模型;最后,将计算结果与试验结果进行了比较分析,模型计算结果与试验结果吻合较好,证明了模型的合理性,同时讨论了贯通节理倾角、非贯通节理倾角对岩体峰值强度及破坏准则的影响,以及非贯通节理贯通率对初始损伤变量影响规律。     

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     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.