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依托上海14号线桂桥路站管幕段实例工程,对管幕群顶管顶进施工过程地面沉降情况进行监测,分析群顶管施工对地面沉降的影响,在此过程中对本工程采用水土分算或合算进行讨论。根据顶进过程实际工况和监测数据,分析管幕群顶管施工影响地面的原因,提出相应控制措施。结果表明:①管幕群顶管施工引起最大地面沉降出现在始发井出加固区区域;②在本工程中采用水土合算计算正面土压力较为符合实际情况;③管幕群顶管施工过程中影响地面变形的因素主要包括前舱压力、顶进速度、洞门止水、管壁摩擦和同步注浆等方面。 相似文献
37.
Mariusz Banaszkiewicz 《Materials at High Temperatures》2019,36(4):354-367
The principal objective of work was to develop fast and accurate method for online creep life monitoring of steam turbine rotors. For this purpose, a characteristic strain model of creep was investigated and validated using test data of 2%CrMoV rotor steel. The model was then used to determine creep damage functions which are introduced to compute creep damage at a constant temperature based on the Robinson time fraction rule. Finite element (FE) creep calculations of a turbine rotor were performed using the same creep model to obtain reference damage results for validating the proposed method. Comparisons of the results obtained using both methods showed a very good accuracy of the online creep damage predictions. 相似文献
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The power systems are functioning nearer to their capacity limits to increase the efficiency of the operation. With the prompt progress of smart grid, wide area measurement system (WAMS) is broadly and rapidly deployed in the EPS to understand, fore-cast, or even control the status of power grid stability in real time. Introducing phasor measurement units in addition to its advances have made them technically viable to monitor the stability of the PS using a wide area perception. This paper presents the review of WAMS and reports the various aspects of its operation in a power system. Initially, WAMS features, components, process, and its architecture are briefly described. The latter provides the data sources along with their standards required for WAMS and its applications. Also this paper gives a brief review on WAMPAC and various research openings for the development and implementation of real-time functions. 相似文献
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基于Atmega16A单片机自主设计一套地压监测系统。整个过程完成了硬件的购置、软件的设计、数据采集程序的编写、系统管线布置方式的设计以及系统的调试等工作。本监测系统的设计及装置的开发具有灵敏度高、功耗低,信号传输可靠、实时、远程和多元化数据监测,后期其他类型数据监测可扩展性强,系统成本低等优点。采集数据的声发射能率分析结果显示,有两次较大的声发射率值与监测范围内两次较大冒顶事故都可以很好的对应。希望该系统的应用能为矿山地下开采过程中地压活动的监测和预警提供技术支持。 相似文献
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Shahid Hussain Xiaoguang Wang Shabbir Ahmad Muhammad Riaz 《Quality and Reliability Engineering International》2020,36(3):910-946
Monitoring of any manufacturing, production, or industrial process can be controlled and improved by removing these special cause of variations using control charts. Shewhart-type control charts are effective to control a large amount of special variations, whereas, cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) charts detect small and moderate variations efficiently in the process parameters. Monitoring of location parameter can be done with mean control charts under the assumption that the parameters are known or correctly estimated from in-control samples and data are free from outliers (but in practice data occasionally have outliers). In this study, we have proposed generalized mixed EWMA-CUSUM median control charts structures for known and unknown parameters based on auxiliary variables for detecting shifts in process location parameter. The proposed charts are compared with the corresponding charts for the mean, based on contaminated and uncontaminated data. Different performance measures are used to evaluate the performance of proposed control charts and revealed through results that the median-based charts are more sensitive to detect a shift in process location parameter in the presence of outliers. An illustrative example using real data is also shown for practical consideration. 相似文献