复杂应力条件下软岩煤巷支护技术对比研究

以古城煤矿1309工作面运输平巷为工程背景,采用FLAC3D数值模拟方法,分析了复杂应力条件下软岩煤巷无支护、传统支护方式及高强预紧力锚网索支护下的巷道围岩变形情况,并对巷道高强预紧力锚网索支护系统进行优化。结果表明,无支护条件下,断层上下盘巷道距断层前后40m范围内受断层影响明显,巷道围岩变形严重;传统支护方式巷道围岩变形较大,无法实现对巷道进行有效的支护;采用高强预紧力桁架锚网索支护方式可以有效控制复杂应力场下软岩煤巷围岩变形。     

矩形巷道支护预紧力对围岩稳定性的影响

以凉水井煤矿3-1煤破碎顶板为研究对象,对锚杆索预紧力对巷道围岩稳定性的影响进行分析。采用数值模拟的方法,分析了不同预紧力条件下,矩形断面巷道围岩的稳定性变化规律,得出不同预紧力情况下,巷道围岩变形及破坏特征,通过数值模拟,提出3-1煤矩形巷道锚杆索支护最佳预紧力方案,以达到充分发挥锚杆索的主动支护作用,降低劳动强度,提高经济效益的目的。     

受高水平构造应力影响的软岩巷道支护技术研究

针对白皎煤矿2410巷遭受高量值水平构造应力影响且围岩极其软弱的特点,对巷道变形特征进行了数值模拟研究。分析了裸巷开挖、低预紧力支护和高预紧力支护条件下巷道变形特征和塑性区分布情况,最终确定高预紧力强力锚杆索联合支护方案。方案实施后,矿压监测结果表明锚杆索预紧力较高时,巷道围岩变形得到有效控制,锚杆索最终稳定工作栽荷与初始预紧力相差不大。     

大断面巷道锚网索支护优化设计

1301工作面两回采巷道变形速度大,支护效果不够理想。运用UDEC数值模拟软件对锚网索支护参数进行了优化设计,对锚杆(索)进行了预紧力设计。现场工业试验巷道围岩变形观测结果表明:巷道支护效果良好,围岩变形得到有效控制。     

深部巷道锚网索支护参数关键因素分析

为了获得深部巷道锚网索支护的关键参数,运用数值模拟计算和正交试验方法,研究了深部巷道锚网索支护参数对巷道两帮及顶底板移近量的影响程度,并采用极差分析法对试验结果进行分析,得出了影响锚网索支护的关键因素。结果表明,锚杆间排距对巷道两帮及顶底板移近量的影响程度最大,依次为锚杆直径、锚杆长度及施加的预紧力。工程实践证明,合理的支护参数使巷道围岩变形明显减小,围岩稳定性得到明显提高。     

深部软岩巷道变形破坏机理及支护对策

针对鹤壁五矿三水平延伸轨道下山巷道破坏特征,对其变形破坏原因和支护对策进行了研究。结果表明:该巷道变形破坏主要是由于自重应力水平高、构造应力影响大、围岩条件差、支护设计不合理等因素造成的。为此,提出了锚网索喷+底角锚杆+柔层桁架支护设计方案,通过锚网索喷支护控制围岩有害变形,底角锚杆切断底板滑移线,柔性桁架保证巷道整体稳定,实现支护一体化、荷载均匀化,从而达到巷道稳定的目的。数值模拟和现场实验结果表明,该支护技术能够有效地控制深部软岩巷道变形,是一种有效的深部软岩巷道支护形式。     

霍尔辛赫矿井大断面煤巷锚网支护技术研究

从理论上分析了霍尔辛赫矿井大断面煤巷锚杆支护体系存在的问题,寻找影响锚网支护的关键因素,得出锚杆(索)的预紧力在支护系统中起关键性作用。采用数值模拟计算方法,分析锚杆预紧力、长度、间距、锚固方式、角度、钢带以及锚索预紧力不同时的应力效果。在霍尔辛赫开拓巷道和3201首采工作面巷道进行井下工业性试验并对锚杆(索)受力进行监测,得出高预应力强力锚杆锚索支护系统(锚杆预紧扭矩400N.m、锚索预紧力300 kN)可提高支护效果,有效控制围岩变形。     

叠加支承压力影响沿空巷道围岩稳定性特征及支护对策

针对急倾斜煤层叠加支承压力作用下沿空巷道围岩变形失稳问题,采用室内试验、数值模拟、理论分析和现场实验相结合的方法,对比研究了回采前后沿空巷道围岩位移、应力分布和塑性区范围等稳定性特征,开展了锚网索联合支护参数敏感性分析。结果表明：固定支承压力下,沿空巷道围岩应力非均匀分布,围岩变形以顶板下沉和两帮非对称变形为主;叠加支承压力作用下,沿空巷道围岩变形加剧,靠近采空区侧煤体弱化程度加深,煤帮及顶、底板岩层深部岩体向塑性状态转变;锚网索主要参数敏感性从强到弱依次为锚杆间排距、锚杆长度和锚杆预紧力。据此提出了非对称锚网索支护方案,有效控制了支承压力叠加影响沿空巷道围岩变形。     

深部软弱围岩大断面切眼支护技术研究

针对红庆河煤矿大采高综采工作面开切眼断面大、埋藏深、巷道围岩软弱、支护困难的情况,提出了仅采用锚网索进行支护的技术。通过数值模拟、现场试验和巷道围岩岩性分析,确定两次开切眼支护参数,锚杆预紧力不低于杆体屈服载荷的40%,采用8m锚索进行补强支护,通过高预紧力强力支护,控制切眼围岩早期的离层和变形。监测结果表明:锚网索支护可以有效地控制深部高应力、软弱围岩、大断面切眼的变形,支护效果好。     

深部倾斜巷道最优断面耦合支护对策

深部倾斜巷道围岩开挖支护后片帮、冒顶和底鼓变形现象严重。分析澄合矿区巷道变形破坏特点后,利用FLAC3D对原支护条件下巷道围岩的变形破坏机制进行数值模拟,并提出了最优断面耦合控制对策,即在优化断面形状的基础上,采用锚网索耦合支护,利用锚索、底角锚杆等对产生变形破坏的关键部位加强支护。可以有效地消除巷道围岩关键部位产生的差异性变形,使巷道围岩稳定性大大提高。     

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。