Optical Fiber Frequency Shift Characterization of Overburden Deformation in Short-Distance Coal Seam Mining

Zhang, Dingding; Chen, Qiang; Wang, Zhengshuai; Yang, Jianfeng; Chai, Jing

doi:10.1155/2021/1751256

Cited by 4 publications

(1 citation statement)

References 30 publications

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“…When the working face is mined, the original rock stress of the overlying rock is redistributed. According to the definition of optic fiber frequency shift variation in the document [21], the size of the optic fiber frequency shift variation is used to characterize whether or not incoming pressure is occurring at the working face. The definition of fiber As shown in Figure 13d-f, when the working face advances to 142.0 cm, the strain curve of the optical fiber adds two new peaks on the original basis.…”

Section: Vertical Fiber Optic Frequency Shift Change To Pressure Char...mentioning

confidence: 99%

Research on Similarity Simulation Experiment of Mine Pressure Appearance in Surface Gully Working Face Based on BOTDA

Zhang,

Huang,

et al. 2023

Sensors

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In order to study the mountain deflection characteristics and the pressure law of the working face after the mining of a shallow coal seam under the valley terrain, a geometric size of 5.0 × 0.2 × 1.33 m is used in the physical similarity model. Brillouin optical time domain analysis (BOTDA) technology is applied to a similar physical model experiment to monitor the internal strain of the overlying rock. In this paper, the strain law of the horizontal optical fiber at different stages of the instability of the mountain structure is analyzed. Combined with the measurement of the strain field on the surface of the model via digital image correlation (DIC) technology, the optical fiber strain characteristics of the precursor of mountain instability are given. The optical fiber characterization method of working face pressure is proposed, and the working face pressures at different mining stages in gully terrain are characterized. Finally, the relationship between the deflection instability of the mountain and the strong ground pressure on the working face is discussed. The sudden increase in the strain peak point of the horizontally distributed optical fiber strain curve can be used to distinguish the strong ground pressure. At the same time, this conclusion is verified by comparing the measured underground ground pressure values. The research results can promote the application of optical fiber sensing technology in the field of mine engineering.

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Section: Vertical Fiber Optic Frequency Shift Change To Pressure Char...mentioning

confidence: 99%

Research on Similarity Simulation Experiment of Mine Pressure Appearance in Surface Gully Working Face Based on BOTDA

Zhang,

Huang,

et al. 2023

Sensors

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Kriging interpolation reconstruction of surrounding rock moisture content field

Zhang,

Qin,

Yuan

et al. 2023

Environ Earth Sci

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Mantle-Derived Helium Distribution and Tectonic Implications in the Sichuan–Yunnan Block, China

Meng

Zhou

et al. 2021

ACS Omega

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The geochemical characteristics of mantle degassing observed on the surface of the earth can indicate the origin and migration path of mantle fluids. Compared with the plate boundary tectonic environment, the intraplate tectonic environment does not have a large number of active volcanoes and active faults, and the observation of mantle volatiles in hot spring gas is relatively limited. We selected the Sichuan–Yunnan block to discuss mantle degassing based on the carbon and noble gas isotopes of the spring gases and previous studies on the fault slip rate and geophysical research. A total of five hot spring gas samples (including two free gases and three dissolved gases) were collected from the Sichuan–Yunnan block. Chemical and isotopic compositions were analyzed in N2-dominant hot spring gases. The 3He/4He ratio (0.068–0.541 R a) indicates the occurrence of mantle-derived helium throughout the Sichuan–Yunnan block, which has been diluted by a crustal radiogenic 4He component. The occurrence of mantle-derived helium in the study areas ranges from 0.74 to 5.67%. The lower proportion of mantle-derived helium in YNWQ and HGWQ than that in other spring gases near the Jinghe-Qinghe fault may be caused by the smaller scale of fault around YNWQ and HGWQ than the Jinghe-Qinghe fault. The correlation between 4He, 20Ne, and N2 concentrations implies a common trapping mechanism for 4He, 20Ne, and N2 in hot spring gases. The 40Ar/36Ar ratios and N2/Ar ratios indicate that N2 and Ar are mostly meteoric, and YNWQ and HGWQ have more crustal-derived Ar contribution (40.56 and 51.49%, respectively). The δ13C(CO2)o values calculated by Rayleigh fractionation and CO2 concentration suggest that CO2 has inorganic and organic origins. The plot of R c/R a versus δ13C(CO2) indicates that the spring gas CO2 origin in the Sichuan–Yunnan block is mainly derived from mixing of limestone and organic sediments with minor mantle CO2. The δ13C(CH4) versus CH4/3He values indicate that the origin of methane is thermogenic and microbial oxidation. The low mantle-derived helium distribution pattern is most likely controlled by the weak fault activity rate, the small fault scale, and not obvious magmatic activity in the Sichuan–Yunnan block.

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Optical Fiber Frequency Shift Characterization of Overburden Deformation in Short-Distance Coal Seam Mining

Cited by 4 publications

References 30 publications

Research on Similarity Simulation Experiment of Mine Pressure Appearance in Surface Gully Working Face Based on BOTDA

Research on Similarity Simulation Experiment of Mine Pressure Appearance in Surface Gully Working Face Based on BOTDA

Kriging interpolation reconstruction of surrounding rock moisture content field

Mantle-Derived Helium Distribution and Tectonic Implications in the Sichuan–Yunnan Block, China

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