浅埋暗挖隧道铣挖开挖方法研究

隧道暗挖法施工具有对地面交通干扰小、对环境污染少等优点,在越来越多的城市隧道工程中被采用,但施工爆破振动和噪声会给城市居民生活造成一定影响。结合杭州市紫之隧道浅埋暗挖段的施工情况,对多种隧道开挖技术进行比较,分析控制爆破开挖方法对周边环境的影响,提出采用铣挖开挖施工的方案,并对施工效果从开挖成形、地表沉降、施工进度和经济指标等方面进行了分析。     

挖掘机液压属具铣挖机国内外发展概况

目前在隧道施工、市政管线开挖、路面破碎维修、建筑物拆除、岩石冻土挖掘等施工中,普遍采用液压破碎锤破碎施工、掘进机掘进施工以及爆破施工方法,使用铣挖机施工替代上述方法,将体现出高效、精确、破坏性小、噪音低、污染轻、节能降耗等优点。文中简述铣挖机工作原理、应用范围以及国内外主要生产厂商产品的技术特点与技术参数,以及铣挖机国内外发展现状。     

软岩隧洞爆破超挖对施工进度与成本的影响及改进措施

以新疆奎屯河引水隧洞项目2标段工程为例,分析了隧道超挖产生的原因,结合工程实际计算了超挖对施工进度和施工成本的影响程度。计算结果表明:V类围岩隧道超挖10 cm时,每延米工时增加29 min,总工期增加69 d;隧道超挖10 cm,每延米平均增加的成本为3 527.987元,总标段增加1 206.6万元。为减少隧道超挖,从钻孔工艺、爆破参数设计和工程管理三个方面,提出了相应的改进措施。实施改进措施后,爆破质量得到大幅提高,经济效益提高49.87%,时间效益提高48.28%。     

公路隧道爆破掘进超欠挖的原因分析及施工对策

通过对隧道施工中超欠挖问题的分析和研究,提出了容易造成超欠挖的各项原因,并对这些原因进行分析,通过工程实例所取得的良好效果和经验总结,提出了提高测量放线精度、提高钻孔精度、重视钻爆设计、加强现场施工管理和组织等解决措施.对于提高隧道工程质量、加快施工进度、减少施工成本具有重要的意义.     

基于盾构隧道冻结扩挖施工的数值模拟研究

为研究在盾构隧道基础上进行冻结扩挖施工的可行性,本文以郑州地铁3号线二七广场站暗挖段的盾构隧道扩挖工程为背景进行研究.该段工程埋深浅、断面大、地下水位极低,且位于富水粉细砂层,施工风险和难度极高.本文考虑冻结与不冻结降水等4种工况,采用PLAXIS软件建立车站盾构隧道扩挖模型,对盾构隧道扩挖施工过程进行数值模拟,并通过...     

金丽温高速公路红枫连拱隧道超欠挖分析

超欠挖一直是隧道开挖中遇到的一大难题。该文在金丽温高速红枫连拱隧道超欠挖现象现场调查的基础上,绘制出开挖断面超欠挖块体投影面的平面展示图,对超欠挖现象的各种几何形态进行统计分析,包括投影面的边分析、面分析和块体的空间分布、超欠挖深度、体积分析。统计连拱隧道超欠挖块体空间几何和体积等分布特征,得出开挖断面上不同弧段的超欠挖差异,最后估算由于超欠挖而造成的对隧道成本的影响以及不同弧段超挖造成增加投入的差异。     

机械破岩在破碎矿体进路回采中的应用

破碎软岩矿体使用进路式钻爆法回采时,爆破振动导致进路围岩难以实现自稳,掘进过程进路易冒顶、片帮,支护工作量大,采矿效率低下。为解决上述问题,夏家店金矿引进铣挖机机械采矿代替钻爆法采矿。研究了铣挖机机械破岩机理,对比分析了铣挖机机械采矿与钻爆法采矿在作业安全性、生产效率、经济效益等方面的差异。结果表明：铣挖机机械采矿可代替矿山85%的钻爆法采矿;铣挖机机械采矿的进路稳定性提高,采矿效率提升了50%以上,支护工作量减少了近40%;矿石回采率增加了6.4个百分点,采矿成本降低了45.5元/t,取得了良好的安全效益、经济效益、社会效益。     

公路隧道超欠挖原因分析及控制措施

分析了公路隧道超欠挖产生的原因，提出了降低或减少隧道超欠挖的措施，指出采用“新奥法”技术、强化施工管理是控制隧道超欠挖的关键，可供隧道施工时参考。     

隧道岩爆分类及防治对策

隧道发生岩爆,不仅会对施工安全构成威肋,而且可能造成严重的超挖、增加工程造价甚至延误工期.根据隧道岩爆的特点,总结了国内岩爆的分类方法,并提出了从设计、施工、支护加固处理措施到质量管理的隧道岩爆防治对策,以避免和减少隧道岩爆的发生.     

山岭隧道浅埋段盖挖法施工技术

针对新建铁路成都-贵阳线新田坳隧道、祠堂山隧道、棉花山隧道下穿沟谷时埋深不足4m且大小里程两端地势陡峭的工程特点,经过明挖、暗挖、盖挖方案综合比选,最终采用盖挖法施工,避免了大面积明挖对生态环境的破坏,又规避了暗挖法隧道冒顶坍塌的危险。经过盖挖法在三座隧道浅埋段的应用,证明盖挖法在山岭隧道浅埋段施工中对提高施工速度、减少投资、降低施工安全风险、加强环境保护等方面具有很大的优势。     

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。