新建隧道施工对邻近既有运营地铁隧道的变形影响

随着城市轨道交通的快速发展,新建地铁隧道穿越或者邻近既有建筑结构的工况越来越普遍,如何将新建隧道对既有建筑的影响降低到最小程度,保证其结构安全、正常运营,已成为地铁修建过程中的一个重要研究内容。以郑州市某新建隧道明挖段和暗挖段施工为例,采用有限元软件Midas GTS建立数值计算模型,分析新建隧道施工对既有运营地铁隧道的变形影响规律,并与实际工程监测数据进行对比验证。研究结果表明：1)明挖段基坑开挖完成后,既有运营地铁隧道的最大竖向变形和水平变形分别为0.57、1.21 mm; 2)暗挖段施工完成后,既有运营地铁隧道的最大竖向变形和水平变形分别为0.27、0.39 mm; 3)实际监测数据略小于数值计算结果。本文结果可为类似工程提供一定的借鉴和参考。     

明挖基坑上跨既有运营地铁隧道施工关键技术与实践

基于苏州星港街隧道上跨地铁1号线明挖基坑工程实践,分析上跨基坑施工过程中既有隧道保护的重难点,采取了非原位试验、基坑分块开挖优化、隧道内自动化监测等施工关键技术。通过对施工中变形监测情况进行分析,对此类上跨项目采取门式加固、抗拔控沉桩、地基加固、监控量测、分块开挖、限时回筑等措施,可满足施工中对运营隧道的保护要求,为今后类似上跨基坑工程的建设提供参考。     

测量机器人在地铁隧道自动化监测中的应用

由于地铁隧道运营的特殊环境,传统的测量方法已不能满足地铁隧道变形监测的需要,测量机器人采用自动搜索、跟踪、照准等智能化测量功能,系统在计算机的控制下实现全自动、高精度的变形监测.保障隧道结构及地铁运营安全.     

地铁单圆隧道横断面变形监测研究

为了确保地铁运营的安全,地铁隧道结构的变形监测至关重要。该文根据地铁单圆隧道的环片拼装特点,对隧道横断面收敛变形监测方法进行优化。即按照最小二乘法将每个环片进行圆弧拟合,求出横断面的中心坐标,横断面上各点到中心的距离与隧道设计值的较差为环片的变形量;最后,利用C#编写数据断面处理程序,能够快速导入数据并将计算的变形结果可视化显示,对维护地铁隧道结构的安全运行有重要意义。     

基于小波的运营地铁隧道自动化变形监测数据处理

受邻近基坑施工影响的运营地铁隧道的位移变形监测常采用基于测量机器人的自动化监测系统,得到的变形监测数据具有观测周期长、监测精度高、累计位移小的特点,难以从观测数据中辨别真实位移和观测误差。该文采用小波变换方法对监测数据进行去噪声处理,提取变形趋势,从而可以清晰地得到变形规律,为优化基坑施工方案,指导类似工程提供有效的技术支持。     

地铁换乘通道暗挖段施工对既有盾构隧道的影响研究

以深圳地铁7、10号线福民站换乘通道暗挖段工程为依托,采用数值模拟方法,评估换乘通道暗挖段施工对既有地铁隧道的影响并分析其规律。通过数值分析,得到了以下结论:暗挖通道的施工对既有盾构隧道管片的受力影响较小,既有管片的受力不会因为暗挖通道的施工出现较大变化;上覆换乘通道的开挖造成的卸载效应会导致既有盾构隧道出现轻微的隆起变形,其最大变形值为1.66mm,出现在通道开挖完成而底板尚未施作的阶段;依据设计方案进行地铁换乘通道暗挖段的施工,不会对既有地铁隧道的结构安全及运营安全产生影响。     

基坑开挖对邻近既有地铁结构变形影响的数值分析与研究

既有地铁结构可能因邻近基坑工程施工而产生变形,在一定程度上会对地铁线路的正常运营产生影响。该文以天津市某邻近深基坑工程的既有地铁线路为例,采用PLAXIS 3D有限元数值模拟分析法建立三维空间实体模型,对邻近地铁结构的基坑Ⅰ、Ⅱ施工过程进行模拟,分析计算地铁车站主体结构、隧道管片的位移,以此来研究基坑施工对邻近既有地铁结构变形的影响。研究结果表明,基坑大面积开挖产生的卸荷效应显著,从而导致地铁结构产生一定的水平位移和沉降。距离地铁结构最近的基坑Ⅰ三期对地铁结构水平位移的影响最为明显。提出在其之间预设注浆纠偏措施的同时应加强变形监测,以保证隧道安全。计算所得各项变形指标均在变形控制标准之内。     

地铁盾构工程隧道施工对周边环境影响第三方监测

地铁盾构工程隧道施工通过不良地质条件地段过程中对地层产生扰动,可能引起地表及周边建筑物变形或沉降,尤其是隧道穿过正在施工的基坑止水幕墙,可能拉裂幕墙危及基坑及附近建筑物安全,因此必须进行监测。介绍了地铁盾构工程隧道施工过程中的第三方监测及经验、体会,希望对同类施工有所借鉴。     

地铁隧道变形监测现状分析

为了保证城市地铁安全,需要对地铁隧道进行全方位的变形监测。本文论述了当前地铁隧道变形监测的现状,介绍了地铁隧道监测采用的技术,总结了地铁隧道变形监测的内容和方法,对未来地铁监测的发展作了简要的展望,本文的研究为工程技术人员提供了参考。     

紧邻地铁隧道的深基坑地下连续墙施工技术

所建工程紧邻运营中的地铁隧道,施工难度和风险极大,通过对地下连续墙施工关键时段工序的分析,采用加强工序的穿插和衔接,辅以技术保证措施,在施工中加强信息化的施工监测,确保了地铁的安全和施工的成功.     

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     

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     

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.     

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.     

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