Strain Transfer of Bonded FBG Sensor for Coal Mining Similar Model

2015 ◽  
pp. 20-28
Author(s):  
Guihua Zhang
2011 ◽  
Vol 33 (2) ◽  
pp. 539-548 ◽  
Author(s):  
Benjamin Torres ◽  
Ignacio Payá-Zaforteza ◽  
Pedro A. Calderón ◽  
Jose M. Adam

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1318 ◽  
Author(s):  
Tao Hu ◽  
Gongyu Hou ◽  
Zixiang Li

Mining deformation of roof strata is the main cause of methane explosion, water inrush, and roof collapse accidents amid underground coal mining. To ensure the safety of coal mining, the distributed optical fiber sensor (DFOS) technology has been applied in the 150,313 working face by Yinying Coal Mine in Shanxi Province, north China to monitor the roof strata movement, so as to grasp the movement law of roof strata and make it serve for production. The optical fibers are laid out in the holes drilled through the overlying strata on the roadway roof and BOTDR technique is utilized to carry out the on-site monitoring. Prior to the on-site test, the coupling test of the fiber strain in the concrete anchorage, the calibration test of the fiber strain coefficient of the 5-mm steel strand (SS) fiber, and the test of the strain transfer performance of the SS fiber were carried out in the laboratory. The approaches for fiber laying-out in the holes and fiber’s spatial positioning underground the coal mine have been optimized in the field. The indoor test results show that the high-strength SS optical fiber has a high strain transfer performance, which can be coupled with the concrete anchor with uniform deformation. This demonstrated the feasibility of SS fiber for monitoring strata movement theoretically and experimentally; and the law of roof strata fracturing and collapse is obtained from the field test results. This paper is a trial to study the whole process of dynamic movement of the deformation of roof strata. Eventually the study results will help Yinying Coal Mine to optimize mining design, prevent coal mine accidents, and provide detailed test basis for DFOS monitoring technique of roof strata movement.


Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1851 ◽  
Author(s):  
Li Sun ◽  
Chuang Li ◽  
Chunwei Zhang ◽  
Tianqi Liang ◽  
Zihao Zhao

This research focuses on a desensitization method to develop a wide-range FBG sensor for extra-large strain monitoring, which is an essential requirement in large scale infrastructures or for some special occasions. Under appropriate hypotheses, the strain transfer distribution of wide-range FBG sensor based on the shear-lag theory is conducted to improve the accuracy of extra-large strain measurements. It is also discussed how the elastic modulus of adhesive layer affects the strain transfer rate. Two prototypes in different monitoring ranges are designed and fabricated by two layers of steel pipe encapsulation. The presented theoretical model is verified by experimental results. Moreover, it is demonstrated that experimentation in regards to the calibration of the wide-range FBG sensor, improved the amplification coefficient up to 2.08 times and 3.88 times, respectively. The static errors are both calculated and analyzed in this experiment. The wide-range FBG strain sensor shows favourable linearity and stability, which is an excellent property of sensors for extra-large strain monitoring.


2014 ◽  
Vol 578-579 ◽  
pp. 1037-1041 ◽  
Author(s):  
Li Sun ◽  
Bo Zhang ◽  
Chuang Li ◽  
Chuan Yun Yue

The FBG sensors of measuring stress and strain on the surface of concrete are mainly based on substrate encapsulation in engineering. Since the substrate encapsulation FBG sensor has a multilayer structure, there is certain consumption when the stress is transferred from the surface of concrete to optical fiber, which leads to difference between measured value and actual value. This paper analyzes the influencing factors of strain transfer rate by the method of theoretical calculation and finite element analysis. The formula of strain transfer is thereby obtained.


1886 ◽  
Vol 22 (560supp) ◽  
pp. 8940-8940 ◽  
Keyword(s):  

2013 ◽  
Vol 7 (4) ◽  
pp. 456-474
Author(s):  
Beatrice Monaco

This paper explores some key texts of Virginia Woolf in the context of Deleuzian concepts. Using a close reading style, it shows how the prose poetry in Mrs Dalloway engages a complex interplay of repetition and difference, resulting in a remarkably similar model of the three syntheses of time as Deleuze understands them. It subsequently explores Woolf's technical processes in a key passage from To the Lighthouse, showing how the prose-poetic technique systematically undoes the structures of logical fact and rationality inscribed in both language and everyday speech to an extremely precise level.


2001 ◽  
Vol 23 (2) ◽  
pp. 91-103
Author(s):  
JAMIE HAMILTON ◽  
CIARA CLARKE ◽  
ANDREW DUNWELL ◽  
RICHARD TIPPING

This report presents the results of the excavation of a stone ford laid across the base of a small stream valley near Rough Castle, Falkirk. It was discovered during an opencast coal mining project. Radiocarbon dates and pollen analysis of deposits overlying the ford combine to indicate a date for its construction no later than the early first millennium cal BC. Interpreting this evidence was not straightforward and the report raises significant issues about site formation processes and the interpretation of radiocarbon and pollen evidence. The importance of these issues extends beyond the rarely investigated features such as fords and deserve a larger place in the archaeological literature.


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