提高立井井壁混凝土强度等级的原理及其途径

通过对现行混凝土井壁和钢筋混凝土井壁设计公式分析，指出了提高井壁承载能力和降低井筒工程造价的最好方法是提高井壁中的混凝土强度等级，并通过试验分别采用高效减水剂和硅配制出了Ｃ５８和Ｃ６３级井壁高强混凝土。     

深厚表土层冻结井筒高强钢筋混凝土内壁设计优化与实测分析

针对深厚表土层冻结井筒内壁设计厚度较大问题,对高强钢筋混凝土内壁的受力机理、设计优化方法、现场实测结果进行了分析研究。首先,采用相似理论设计出模型井壁并进行加载试验,实测得到高强钢筋混凝土内壁的应力、变形和承载力,研究了该种井壁结构的受力机理,结果表明深厚表土层冻结井筒内壁属于深埋于地下的厚壁圆筒结构物,由于内表面的圆形结构特征,在侧向压力作用下,井壁结构中混凝土由外缘的三向受压过渡到内缘的二向受压应力状态,其混凝土抗压强度提高了1.592～1.765倍,井壁承载能力得到显著提高。建立了混凝土抗压强度提高系数试验值的计算公式,获得了高强钢筋混凝土内壁的应力特性和强度特征。然后,基于我国现行混凝土结构设计规范关于混凝土多轴强度验算要求,根据模型试验结果和内壁受力机理,提出了深厚表土层高强钢筋混凝土内壁设计优化方法,给出了混凝土抗压强度提高系数设计取值。并将设计优化方法应用于潘三煤矿新西风井冻结段内壁控制层位,井壁厚度由原设计的1 150 mm优化为900 mm,厚度减薄达21.74%。最后,通过潘三煤矿新西风井工程现场实测表明,优化设计后的井壁结构中环向钢筋应力值为-125.8～-136.9 MPa、竖向钢筋应力值为-39.5～-53.2 MPa,远小于钢筋强度设计值300 MPa,井壁中混凝土环向应变为-730×10~(-6)～-790×10~(-6)、竖向应变为-380×10~(-6)～-390×10~(-6),远小于C70混凝土的极限压应变值,说明设计优化后的井壁结构不但经济合理,而且安全可靠。     

高强钢筋混凝土井壁模型试验研究

介绍了模型试验情况，分析了高强钢筋混凝土井壁的变形和强度特征，给出了计算井壁极限承载能力的经验公式。     

冻结井高强钢筋混凝土预制弧板井壁试验研究

提出一种新型的冻结井高强混凝土预制弧板外层井壁结构形式，通过原材料强度模型试验，研究了其力学形态和极限承载力．研究表明，该种新型井壁结构形式具有在井下装配后即可满负荷工作，承载能力大、受力特性好等优点，适用于400m以上深厚表土层冻结井外层井壁支护．     

内层钢板高强钢筋混凝土复合井壁在冻结井筒应用研究

针对板集主井井壁修复工程,提出采用内套内层钢板高强钢筋混凝土复合井壁。对该种井壁受力机理进行分析,井壁内缘混凝土由于受到钢板筒的约束而处于三向受压应力状态,抗压强度明显增加,而该种井壁的现行设计计算方法并没有考虑到这一点。为此,根据我国现行混凝土结构设计规范中有关内容,给出内层钢板钢筋混凝土复合井壁设计计算完善方法。模型试验证明,采用完善方法设计的内层钢板高强钢筋混凝土复合井壁结构,其混凝土抗压强度提高了1.838~1.859倍。板集主井工程应用现场实测表明,井壁结构中混凝土环向应变值为-392με,说明采用完善方法设计的井壁结构安全可靠。     

张集煤矿大直径钻井井壁预制施工实践

张集煤矿风井区2个大直径井筒共244节钻井井壁在地面预制,井壁结构分为钢筋混凝土和双层钢板混凝土2种,井壁混凝土强度等级最高达到C80。在预制井壁施工中,采用了先进的混凝土泵送工艺,简化了施工环节,降低了劳动强度,加快了施工速度,提高了井壁质量,杜绝了过去高强混凝土预制井壁浇筑中产生的蜂窝、麻面、空洞、烂根等现象,取得了良好的技术经济效益。     

高强素混凝土井壁结构强度的试验研究

将高强素混凝土井壁进行模拟试验，得到了井壁在竖向和侧向压力作用下结构强度的试验结果，利用理论和试验相结合的方法推导出井壁结构强度破坏的表达式。     

高强素混凝土井壁结构强度的试验研究

将高强素混凝土井壁进行模拟试验，得到了井壁在竖向和侧向压力作用下结构强度的试验结果，利用理论和试验相结合的方法推导出井壁结构强度破坏的表达式。     

深井马头门处沥青块钢骨混凝土井壁结构的研究与应用

针对淮南新集一矿西区副井马头门及下段井筒处于强膨胀性泥岩地层中,对该马头门处立井井壁进行设计优化,选用了一种沥青块钢骨混凝土新型井壁结构。该井壁为沥青块缓冲层、密集槽钢井圈和钢筋混凝土的复合结构。采用有限元数值模拟方法,对钢骨混凝土井壁和原设计钢筋混凝土井壁的力学特性进行了对比分析。结果表明,相对于钢筋混凝土井壁,钢骨混凝土井壁的极限承载力可提高22%。沥青块钢骨混凝土井壁内力的现场监测结果表明,沥青块层具有较好的缓冲作用和调压效果,井壁结构受力状况良好且安全储备较高,进而验证了井壁结构优化方案的合理性和可靠性。     

高强混凝土在立井井壁中的应用及展望

高强混凝土是一种品质优良的建筑材料，具有强度高、变形小、良好的抗渗性和抗冻性。将高强混凝土用于深厚表土层立井井筒工程中，能满足我国不断加深的钻井和冻结井简建设的需要。高强混凝土复合井壁具有减小井壁厚度，防止井壁渗水，降低建井成本的优点。介绍了我国煤矿立井使用高强混凝土所取得的经验，提出了今后深厚表土层中高强混凝土复合井壁的结构形式，以便更好地推广和应用高强混凝土井壁，解决深厚表土层立井支护的难题。     

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

正~~     

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