FLAC在老采空区地基稳定性评价中的应用研究

以皖北某矿老采空区上方地基稳定性评价为例,研究了应用FLAC进行老采空区地基稳定性评价的过程与方法。研究表明,使用FLAC模拟老采空区地表移动和变形必须对岩层参数进行修正。模拟计算结果显示,老采空区地表残余移动变形与一般开采条件下主断面地表移动和变形具有相同的分布规律,在载荷作用下,地表移动和变形的大小范围均增大,该区域地表残余移动变形不会影响新建建筑物的安全使用。     

开滦唐家庄矿采空区上方地基稳定性评价

针对原唐家庄矿工业场地下方采空区的具体条件,通过地表残余移动变形预计、建筑物载荷影响评价、煤柱长期稳定性分析等方法,对老采空区上方地基稳定性进行了评价。     

浅部多煤层开采形成的老采空区地表兴建建筑物可行性研究

以北票矿区某浅部多煤层开采形成的老采空区地表兴建建筑物地基稳定性评价为例,结合老采空区塌落、上覆岩层压密及裂隙分布情况,从覆岩厚度、建筑物荷载对老采空区覆岩的影响、地表非均衡破坏以及地表残余变形的预计进行了分析,对地表兴建建筑物可行性进行了研究.研究结果表明,即使老采空区裂隙带处于建筑物载荷的影响范围之内,对地表残余变形及非连续变形发生情况充分预估,对拟建建筑物采取相适应的抗采动影响措施,或者对可能造成地表出现非连续变形的未塌落采空区进行处理,在浅部老采空区地表兴建建筑物是可行的.     

某金矿浅部老采空区活化对竖井变形的影响

山东某金矿浅部山体塌陷与地表移动变形严重影响了竖井正常提升与井下安全生产。故采用地球物理勘探、钻探及洞穴激光扫描方法对该矿老采空区的赋存情况进行了验证探测,发现矿区浅部留有大量的老采空区,认为浅部矿体的重复采动引起老采空区活化,是导致山体塌陷、地表移动及竖井变形的根本原因。在上述分析的基础上,应用概率积分法分析老采空区全部活化与深部开采对竖井变形的影响,为该矿竖井安全运营及老采空区治理提供了可靠依据。     

基于D-InSAR技术的金矿老采空区下沉监测与位置反演

为合理回收黄金资源,山东某黄金矿山对部分浅部老采空区残留的矿体进行了再次开采,重复采动破坏了地层的应力平衡状态,引起了老采空区"活化",导致地表发生移动变形,对地面建(筑)物带来了损害影响。为控制地表下沉危害,需要对"活化"的老采空区进行注浆处理,从而有必要准确确定"活化"采空区的位置。利用地表下沉信息反演"活化"采空区位置,结合合成孔径雷达差分干涉测量技术(Differential Interferometry Synthetic Aperture Radar,D-InSAR),运用ALOS-1卫星和哨兵1A卫星数据提取了该矿区部分时间段的下沉量分布信息,并将D-InSAR监测结果与前期水准实测数据相结合,分析了矿区下沉的变化规律,确定了岩层移动参数,反演出了"活化"采空区的位置。研究表明:该矿区下沉活动仍在发生,但下沉速率明显放缓,2007年以后采取的充填治理方案效果显著;尽管金矿开采地表下沉量较小,应用D-InSAR技术仍然能够快速获取下沉信息,可进一步根据地表下沉信息反演"活化"采空区的具体位置。研究结果可为矿区采用D-InSAR技术监测地表沉陷以及反演矿井地下开采空间的动态发展过程提供有益参考。     

采空区活化失稳关键因素模拟分析

以采空区采动破碎次生岩体为主要研究对象,通过理论分析,对采空区活化影响因素进行了分析,确定了具体工程条件下主要活化因素为充水、建筑荷载。以是否充水、建筑荷载大小为控制因素设计数值模拟方案,得到不同工况下的地表移动变形规律。研究发现,水对破碎岩体变形具有促进作用。通过对4~#煤和9~#煤按照每层0.015 MPa和每层0.1 MPa的建筑荷载进行梯度加载,模拟结果得到4~#煤采空区覆岩地基允许施加荷载为0.045 MPa,影响深度为19 m,不满足建筑物地基建设要求,需要对4~#煤采空区采取加固处理;9~#煤采空区覆岩地基允许施加荷载为2.0 MPa,地基扰动深度70 m,满足设计要求。     

老采空区地基稳定性模拟分析

利用FLAC2D有限差分程序对老采空区上方地表新建建筑物载荷作用下的地基稳定性进行了模拟分析.研究结果表明,该方法是可行的.为老采空区上方新建建筑物地基稳定性的评价提供了一种新的分析方法.     

采煤塌陷区上方大型厂房建设技术研究

针对采煤塌陷地上建设大型厂房的安全技术问题,以平顶山市某机械制造公司拟建厂区为例,在分析地下采空区特征及分布情况的基础上,通过选取合理的计算参数,采用概率积分法计算了建设场地后续的地表残余沉陷变形。采用经验公式计算了老采空区垮落裂隙带高度,并对比建筑荷载影响深度评价了地基稳定性,分析了老采空区"活化"的可能性。研究表明:新建厂房下方存在3层煤采空区,建筑物后续将承受Ⅰ级残余沉陷变形,由于采空区采深较大不会导致"活化"情况发生。根据地表水平变形这一影响大型钢结构厂房安全性的主要因素的量级情况,提出了针对大型厂房结构特征的抗变形技术措施。工程实践表明,老采空区上建设大型建(构)筑物是安全可行的,可以兼顾功能需要和安全性能,具有较好的技术经济效益。     

老采空区地基稳定性评价及分区研究

为了研究老采空区地基稳定性问题,以徐州市经济技术开发区某场地为例,从采空区三带模型出发,对采空区地表变形机理及基本规律进行研究,在此基础上结合矿区煤层可采边界及地表移动变形参数,使用地表开采沉陷预计系统MSPS对采空区引起的地面残余变形程度进行预测。研究结果表明:目前场地地表移动变形的活跃期已经结束,未来的地表沉降变形将以残余变形为主,并根据残余变形程度对采空区稳定性进行合理分区,进而对工程建设提出指导建议。     

采空区上方地基失稳机理和处理措施研究

废弃老采空区及其覆岩的结构形态对老采空区"活化"的形式和程度起控制作用,长壁老采空区及其覆岩结构可分为散体结构、碎裂结构、块裂层状结构和较完整层状结构,提出了其相对平衡岩体结构模型.机理研究表明,岩体结构的失稳和采动裂缝、空隙压密是造成长壁老采空区地基"活化"、地表沉降变形的主要原因;并在此基础上提出了"覆岩结构加固补强法"等四种长壁老采空区地基处理措施.某选煤厂主厂房下局部采动破裂地基处理实例研究表明,采用"覆岩结构加固补强法"处理长壁老采空区边界附近破裂岩体地基是可行和可靠的.     

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