Experimental study on PPP-BOTDA distributed measurement and analysis of mining overburden key movement characteristics

Chai, Jing; Ma, Zhe; Zhang, Dingding; Yuan, Qiang; Lei, Wulin

doi:10.1016/j.yofte.2020.102175

Cited by 13 publications

(7 citation statements)

References 6 publications

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“…Along with the fracture position of the rock beam, the compressive stress value is in the range of −42.0 ∼ −27.0 kPa. Advances in Civil Engineering e analyzing results are essentially consistent with general cases [41][42][43][44][45], which means that the V-P FEM is useful to detect the failure mode.…”

Section: Maximum Principle Stress Figurementioning

confidence: 54%

Analysis for Overburden Destruction on Lateral Boundary of Stope Based on Viscoelastic‐Plastic Finite Element Method

Yin

Liu

et al. 2021

Advances in Civil Engineering

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In longwall mining, the deformation and destruction of overlying strata always lag behind coal extraction. The overlying strata characteristics at the lateral boundary of the stope can be classified into four categories, i.e., Hard-Soft, Soft-Hard, Hard-Hard, and Soft-Soft. In order to analyze the effect of the above four structures, we adopt viscoelastic theory to the finite element method (FEM) and define the point safety factor to evaluate the rock damage. The accuracy of programming is verified through example verification. A modified viscoelastic-plastic FEM model is applied to analyze the performance of four overburden structures. The numerical computation results show the following: From the rupture of overburden rock to its stabilization, the duration time of four typical structures can be sorted as “Soft-Soft < Hard-Soft < Soft-Hard < Hard-Hard”. The fracture direction and dip angle of each structure vary as well. The fracture zone of the H-S structure is inclined toward the goaf, while that of the S-H structure is inclined to the lateral boundary of the stope. The fracture zone of the H-H structure is also inclined toward the lateral boundary, with a greater angle than the S-H structure, while the fracture zone of the S-S structure is inclined to goaf, with a greater angle than the H-S structure.

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Section: Maximum Principle Stress Figurementioning

confidence: 54%

Analysis for Overburden Destruction on Lateral Boundary of Stope Based on Viscoelastic‐Plastic Finite Element Method

Yin

Liu

et al. 2021

Advances in Civil Engineering

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“…Now, the commercial BOTDA system, named DiTeSt produced by Omnisens, reached the measuring distance of 30 km, the measuring accuracy of ±20µε and the spatial resolution of 500 mm. The Neubrex Company in Japan produced PPP-BOTDA (pulse-pre-pump optical time domain analysis); the measuring accuracy and spatial resolution of the instrument reached 10µε and 100 mm, respectively, which has been used for [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Measurement Improvement of Distributed Optical Fiber Sensor via Lorenz Local Single Peak Fitting Algorithm

Liu

Zhang

et al. 2021

Symmetry

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Brillouin frequency shift (BFS) of distributed optical fiber sensor is extracted from the Brillouin gain spectrum (BGS), which is often characterized by Lorenz type. However, in the case of complex stress and optical fiber self damage, the BGS will deviate from Lorenz type and be asymmetric, which leads to the extraction error of BFS. In order to enhance the extraction accuracy of BFS, the Lorenz local single peak fitting algorithm was developed to fit the Brillouin gain spectrum curve, which can make the BSG symmetrical with respect to the Brillouin center frequency shift. One temperature test of a fiber-reinforced polymer (FRP) packaged sensor whose BSG curve is asymmetric was conducted to verify the idea. The results show that the local region curve of BSG processed by the developed algorithm has good symmetry, and the temperature measurement accuracy obtained by the developed algorithm is higher than that directly measured by demodulation equipment. Comparison with the reference temperature, the relative measurement error measured by the developed algorithm and BOTDA are within 4% and 8%, respectively.

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“…For example, a displacement measurement device was designed to monitor the internal deformation of the HTC [ 27 , 28 ]. The strain distribution of the whole overburden stratum was revealed [ 30 , 45 , 46 , 47 ]. Then, the HTC was considered as the key stratum to investigate its influence on the overburden rock mechanics and the ground surface subsidence characteristics [ 48 , 49 ].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Deformation Pattern and Movement Law of the Huge-Thick Conglomerate Stratum by a Large-Scale 3D Model Test with Distributed Optical Fiber Sensor Monitoring

Yuan

Chai

Zhang

et al. 2021

Sensors

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Mining activities under the circumstances of huge-thick stratum occurrence commonly result in dynamic response of the working face. It is crucial to understand the rock failure and movement of the huge-thick stratum in order to prevent dynamic hazards. This paper introduces distributed optical fiber sensor (DOFS) monitoring into a large-scale model test to investigate the deformation pattern and movement law of the huge-thick conglomerate (HTC); the monitoring results are verified by numerical simulation. The results indicate that DOFS monitoring captures the spatiotemporal evolution of zoning development in the overburden deformation. The deformation field of HTC is illustrated, and there exists a strain basin that can be used to estimate the movement law of HTC. The average strain variability Ex, a new homogenization index for characterizing the overburden deformation, is proposed to describe the broken rules of the HTC. The numerical simulation proves the feasibility of the DOFS monitoring method and the correctness of the deformation pattern and movement law. This study provides efficient methods for DOFS monitoring utilization to investigate mining engineering problems and could be beneficial for unearthing the mechanisms of deep ground rock deformation.

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Experimental study on PPP-BOTDA distributed measurement and analysis of mining overburden key movement characteristics

Cited by 13 publications

References 6 publications

Analysis for Overburden Destruction on Lateral Boundary of Stope Based on Viscoelastic‐Plastic Finite Element Method

Analysis for Overburden Destruction on Lateral Boundary of Stope Based on Viscoelastic‐Plastic Finite Element Method

Measurement Improvement of Distributed Optical Fiber Sensor via Lorenz Local Single Peak Fitting Algorithm

Investigation of Deformation Pattern and Movement Law of the Huge-Thick Conglomerate Stratum by a Large-Scale 3D Model Test with Distributed Optical Fiber Sensor Monitoring

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