The Characterization Pattern of Overburden Deformation with Distributed Optical Fiber Sensing: An Analogue Model Test and Extensional Analysis

Abstract

The evolution of overburden deformation is crucial for safety and environmental efficiency and its monitoring is becoming a key scientific issue. The use of an optical fiber sensor (OFS) for mining engineering is now receiving praise by virtue of its distinct abilities of distribution, high accuracy, and anti-interference measurement. Nevertheless, the dynamic response of OFS monitoring on overburden deformation still needs to be characterized in detail. This paper analyzed the characterization pattern of overburden deformation based on distributed optical fiber sensing (DOFS) by means of an analogue model test. Then, we discuss the influence of rules of optical fiber embedding on a model test in a numerical simulation. The results show that the DOFS monitoring demonstrates the time-space evolution of overburden deformation and the development of three horizontal areas and three vertical zones. A standardization DOFS characterization model is proposed to expound the characterization mechanism of the overburden structure zoning process; the influence of optical fiber embedding on rock displacement in the model test is revealed, and it is found that the displacement error will increase sharply when the fiber diameter is larger than 2 mm. These findings could provide an effective solution for a monitoring method in intelligent mining from the perspective of a theoretical basis and technological system.

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

“…According to the previous research results of the characterization of overburden deformation with DOFS monitoring [ 49 ], the characterization rules of the zoning development of the mining overburden stratum (i.e., the vertical three-zone development) can be summarized as follows: the height of the caving zone, fractured zone, and bending zone are consistent with the height of the first, second, and third stages of the strain distribution, that is, sections A, B, and C in Figure 4 . As a result, the vertical three-zone development of the overburden stratum can be extracted based on the monitoring results shown in Figure 4 .…”

“…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 ].…”

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

“…Research on the movement of the overlying strata in mining engineering has been a black box problem. Similarity material simulation tests provide an effective solution for studying overburden deformation and rock structure evolution during coal mining [31]. The similarity model was constructed using a 3000 × 200 × 2000 mm (length × width × height) plane stress model frame and based on the geological conditions of the Ningtiaota coal mine.…”

“…The similarity materials were composed of quartz sand, gypsum, and mica powder. These materials were mixed with ratios based on calculation results and the similarity theory [31] (Table 1). The geometric similarity ratio, bulk density similarity ratio, and stress similarity ratio were 1 : 150, 1 : 1.56, and 1 : 234, respectively.…”

Improvement of Performance for Raman Assisted BOTDR by Analyzing Brillouin Gain Spectrum

“…Distributed optical fiber sensing has attracted the attention of researchers in recent years due to its unique advantage in realizing multi-point temperature, strain, and other physical measurements. The Brillouin optical time-domain reflectometer (BOTDR) with probe pulse and signal processing equipment connected at the same end has favorable flexibility [ 1 , 2 ], and thus has been widely applied in power cables, oil and gas pipelines, large-scale structure health monitoring [ 3 , 4 , 5 , 6 ], etc. However, the performance of the distributed optical fiber sensing system in terms of spatial resolution (SR), measurement accuracy, measurement speed, and maximum sensing distance are mutually restricted.…”