Principle of using borehole electrode current method to monitor the overburden stratum failure after coal seam mining and its application

Wu, Rongxin; Hu, Zean; Hu, Xin

doi:10.1016/j.jappgeo.2020.104111

Cited by 12 publications

(4 citation statements)

References 13 publications

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“…The roadway-surrounding rock mass located under the coal seam is subjected to the original rock stress, mining stress, and support stress, which dynamically change when the working face is mined. The change in the stress field in the rock mass and the development of microcracks and macrofractures lead to real-time changes in geoelectric field information 24 , 25 . By monitoring any change in the geoelectric field signal in the rock mass or any abnormal response characteristics, one can comprehend the evolution process of the real-time failure of the rock mass in different areas in the roadway-surrounding rock and take targeted measures for prevention (Fig.…”

Section: Geoelectric Field Monitoring Technologymentioning

confidence: 99%

“…Wu et al revealed the change law of the spontaneous potential in the process of rock mass damage based on numerical simulation, physical simulation test and field monitoring and further mastered the self-potential response characteristics of "three zones" of a coal seam roof in the mining process 23 . Wu et al expounded on the principle of the electrode current method and proposed the method and construction process to monitor mining overburden damage using the borehole electrode current method, which achieved a good application effect in field measurements 24 . Liu et al provided a detailed description of the point discharge occurrence, and the micromechanism of the self-potential anomalies was explained.…”

Section: Introductionmentioning

confidence: 99%

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Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Zhang

et al. 2021

Sci Rep

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The fracture of rocks surrounding the floor roadway during the mining of the working face of a coal mine is a complicated spatiotemporal process due to the superimposed action of multiple stress fields on the surrounding rock mass. Using the surrounding rock of a floor roadway in the working face of the Huainan Pan’er Mine as the research subject, we conducted real-time monitoring using geoelectric field monitoring technology, and found the spatiotemporal response law of the geoelectric field in the process of regional rupture and damage of engineering rock masses under a complex stress field environment. The results show that (1) the time series response characteristics and spatial distribution of the geoelectric field signal are closely related to the stress distribution and damage evolution of the surrounding rock mass; (2) the rupture and damage degree of the goaf floor significantly increased when the working face was pushed through the monitoring area for 20–40 m. During this process, the excitation current dropped by 4–12 mA, and the self-potential pulse fluctuation amplitude was greater than 400 mV; (3) from the beginning of the monitoring process to the end of the monitoring, the self-potential in the damaged area decreased by 250 mV, and the self-potential in the mudstone layer below the damaged area increased by 140 mV. The electrons released into the environment around the damaged rock mass during the severe impact phase of mining did not flow back to the damaged area, and the positive charge in the damaged rock mass gradually accumulated in the complete rock mass in units of rock strata; (4) when superimposed and supported by anchor rod and cables, the bearing capacity of the shallow bearing circle of the roadway was enhanced, and the excitation current presented a step-like overall increase during mining of the working face with a small drop after every significant increase. This result is of significance in monitoring the evolutionary process of real-time failure of rock masses under complex stress environments using geoelectric field information and in improving the quality of geoelectric field monitoring technology testing applications in the future.

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Section: Geoelectric Field Monitoring Technologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Zhang

et al. 2021

Sci Rep

Self Cite

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“…Most of the existing similar models are mainly the twodimensional models, whereas only a handful of threedimensional models are developed due to the limitations of test equipment and sites. Field tests of the deformation damage of the quarry rock include seismic wave lamination method [13], microseismic monitoring method [14], highdensity electrical method [15], and borehole television [16]. Field testing is the most direct testing method to capture the deformation of a rock and the damage under complex geological environment and variables.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Monitoring and Research on the Evolution of the Damage of Weakly Consolidated Coal Floor under Dynamic Pressure Using Distributed Optical Fiber

et al. 2022

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During the extraction of coal seam, the evolution pattern of the rock is an important element for controlling the rock seam and preventing water damage to mine. In order to obtain the deformation and damage of weakly cemented coal seam footings under dynamic pressure, the stability of the footings was studied using a combination of various methods, including rock mechanics testing, field testing, and numerical simulations. By sticking distributed optical fiber on the surface of rock samples, the degree and location of rupture on the surface of rock samples could be obtained using the strain response correlation for optical fiber. Two monitoring holes were arranged in the bottom plate of coal seam at 12307 working face of a mine in Ordos Basin, China. Moreover, a distributed optical fiber sensor was implanted in the hole. The results show that the failure depth was 16.5 m. On the other hand, the numerical simulation results show that the failure depth of the bottom plate was 16.0 m, which agreed well with the measured value. The distribution characteristics of the maximum principal stress of the bottom slab during the advancement of working face were obtained using three-dimensional (3D) numerical model. Based on the distributed optical fiber strain tests in the two boreholes in the same vertical profile and combined with the natural proximal interpolation method, the interhole strain increment distribution profile was obtained. The research results provide a reference for the safe mining of coal resources and the prevention and control of water damage in the mine floor.

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“…Direct observation methods include the drilling TV method and the drilling flushing fluid method (Sun et al 2013). Indirect observation methods include electrical monitoring technology (Wu et al 2020;Ou et al 2020), the acoustic emission monitoring method (AE) , the microseismic monitoring system (MS) (Xia et al 2021), and optical fiber testing technology (Zhou et al 2019). In-situ testing technology is gradually developing in a real-time and accurate direction.…”

Section: Introductionmentioning

confidence: 99%

Study on Deformation and Failure Characteristics of Weak Cemented Roof in Shallow and Extra Thick Coal Seam Mining

Liu

Zhang

Yao

et al. 2021

Preprint

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Detecting the development height of water flowing fractured zone in the roof of coal seam is of great significance for the roof safety of working face with developed sandstone and thick loose layer. This paper analyzes the influence of the induced polarization effect of electrode on the traditional single-mode parallel electrical method. In order to avoid this interference, the dual-mode parallel electrical method is applied to monitor the roof deformation and failure of a coal mine in Ordos Basin. The monitoring results show that: under the influence of mining, the change of geoelectric field of coal seam roof is dynamic, the apparent resistivity of initial mining fracture is high, the apparent resistivity of surrounding rock water filling mining fracture is low, and the apparent resistivity of fracture water flowing to goaf is high again. According to the characteristics of geoelectric field, the maximum height of water flowing fracture zone is 122 M; The average mining coal thickness of the working face is 11 m, and the fracture / mining thickness ratio is 11.1. The results of plastic zone show that the maximum height of water flowing fractured zone above the working face is 122 m, which is consistent with the test results. The vertical stress response characteristics of roof monitoring points are zonal. Under the influence of mining, the loose layer near the surface above the working face is cracked. The edge type ground fissures exist for a long time, and there are a series of geological problems such as soil erosion, ground subsidence.

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Principle of using borehole electrode current method to monitor the overburden stratum failure after coal seam mining and its application

Cited by 12 publications

References 13 publications

Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Dynamic Monitoring and Research on the Evolution of the Damage of Weakly Consolidated Coal Floor under Dynamic Pressure Using Distributed Optical Fiber

Study on Deformation and Failure Characteristics of Weak Cemented Roof in Shallow and Extra Thick Coal Seam Mining

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