Effect of stress amplitude on mechanical and acoustic emission of sandstone under constant–cyclic loading

Zhang, Bichuan; Zhao, Z.; Zou, Quanle; Zheng, Haolong; Ning, Yanhao; Kong, Fanjie; Ran, Qican

doi:10.1007/s10064-023-03307-z

Cited by 6 publications

(3 citation statements)

References 74 publications

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“…Coal is the main energy source that supports the economic development in China (Wu et al, 2022;Sun D. L. et al, 2023;Su et al, 2023). In the recent decade, the raw coal yield in China has always been high (Tan P. et al, 2023;Zhang et al, 2023a;Wu et al, 2023), with huge annual output (Tan et al, 2021;Zhang et al, 2022;Ran et al, 2023a). However, the shallow coal resources are gradually exhausted, and the number of deep coal mines grows by years with the increase in the mining intensity (Zou et al, 2022b;Huang et al, 2023a;Zhao et al, 2023a;Sun X. Y. et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

Xuan,

Cheng,

et al. 2023

Front. Energy Res.

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Influenced by the deep high-stress environment, geological structures, and mining disturbance in coal mines, the frequency of rockburst disasters in roadways is increasing. This research analyzed energy evolution characteristics during rockburst development in the elastic bearing zone and energy conversion in the plastic failure zone. The critical energy criteria for structural instability of roadway surrounding rocks were deduced. Numerical software was also applied to simulate the energy evolution during rockburst development in surrounding rocks of rockburst-prone roadways under conditions of different mining depths and coal pillar widths. The occurrence mechanism of rockburst deep in coal mines was analyzed from the perspective of energy in structures of deep roadway surrounding rock in coal mines. The research results show that the critical energy criteria are closely related to the elastic strain energy stored in deep roadway surrounding rocks and the energy absorbed by support systems. The impact energy in roadways is directly proportional to the square of the stress concentration factor k. Moreover, as the mining depth increases, the location of the peak point of maximum energy density gradually shifts to coal ahead of the working face. The larger the mining depth is, the more significantly the energy density is influenced by advanced abutment pressure of the working face and the wider the affected area is. With the increment of the coal pillar width, the distance from the peak point of energy density to the roadway boundary enlarges abruptly at first and then slowly, and the critical coal pillar width for gentle change in the distance is 30 m. Changes in the peak elastic energy density in coal pillars with the coal pillar width can be divided into four stages: the slow increase stage, abrupt increase stage, abrupt decrease stage, and slow decrease stage. The elastic energy density is distributed asymmetrically in deep roadway surrounding rocks in coal mines. Under the action of structures of roadway surrounding rocks, energy evolution in these structures differs greatly during rockburst development under conditions of different coal pillar widths. This research provides an important theoretical basis for the support of rockburst-prone roadways during deep coal mining.

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Section: Introductionmentioning

confidence: 99%

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

Xuan,

Cheng,

et al. 2023

Front. Energy Res.

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“…With the development of efficient coal mining technologies (Wu et al, 2022;Li et al, 2023a), the spatial scale of fully mechanized working faces in coal mines in China constantly expands in three aspects: mining depth, horizontal scale (including the working face length and advance length), and vertical scale (mainly the mining height) (Liu et al, 2021;Zou et al, 2022a;Ye et al, 2022;Li et al, 2023b;Ma et al, 2023;Sun et al, 2023). In such context, the mining depth of coal increases at a speed of 10-25 m/a, and the working face length gradually increases from 100-200 m to 300-350 m, and even above 400 m in some cases Zou et al, 2022b;Zhang et al, 2023a;Su et al, 2023;Ye et al, 2023). The increases in the burial depth and working face length cause significant changes in strata behaviors (Zhang et al, 2022a;Liang et al, 2022;Ran et al, 2023a), and more pre-existing cracks are found in surrounding rocks of deep mines (Ran et al, 2023b;Zhang et al, 2023b;Zou et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

“…In such context, the mining depth of coal increases at a speed of 10-25 m/a, and the working face length gradually increases from 100-200 m to 300-350 m, and even above 400 m in some cases Zou et al, 2022b;Zhang et al, 2023a;Su et al, 2023;Ye et al, 2023). The increases in the burial depth and working face length cause significant changes in strata behaviors (Zhang et al, 2022a;Liang et al, 2022;Ran et al, 2023a), and more pre-existing cracks are found in surrounding rocks of deep mines (Ran et al, 2023b;Zhang et al, 2023b;Zou et al, 2023). As a result, the weighting in working faces occurs more frequently with a smaller step, in different areas (Wang et al, 2019;He et al, 2022;.…”

Section: Introductionmentioning

confidence: 99%

Three-peak evolution characteristics of supporting stress on a super-long working face in a thick coal seam

Wang,

Cheng,

Zhang

et al. 2023

Front. Energy Res.

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Increasing working face length is the development trend of intelligent and efficient longwall fully mechanized mining. By combining field measurement and theoretical calculation, change characteristics of the frequency, peak value, and range of weighting in a long working face in a 1000 m-deep shaft of Kouzidong Coal Mine (Fuyang City, Anhui Province, China) were studied. Based on the mechanical model of the hydraulic support group of the elastic independent support, force characteristics and posture change characteristics of the support in the 121304 working face of the mine were studied and analyzed. The supporting stress characteristics of the deep super-long working face were revealed, and the theoretical calculation was in good agreement with the actual measurement. Based on the aforementioned model, support parameters and control technology of the 140502 working face were studied. The results show that as the length of the working face increases, the supporting stress gradually transforms from a single peak to multiple peaks and expands to both ends of the working face. The weighting in different areas of the working face is characterized by an obvious time sequence and great difference in intensity. When the working face length is 300 m, the multi-peak characteristic of super-long working faces appears. The M-shaped three-peak characteristic can be used as the criterion for super-long working faces. A reasonable working face length should be determined by comprehensively considering occurrence conditions of coal seams, working face parameter, and equipment ability. According to the different attributes of hydraulic supports in space and function and combining with zonal characteristics of the long working face, the criterion for the super-long working face and the principle of zonal cooperative control of hydraulic support groups were revealed. In addition, a cooperative control method of equipment groups in the working face based on the state error and cost functions was put forward, and the three-level cooperative control strategy and implementation method were formulated. It can effectively guide the equipment group in the super-long fully mechanized working face in deep thick coal seams to achieve optimal coordinated control.

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Morphological evolution and flow conduction characteristics of fracture channels in fractured sandstone under cyclic loading and unloading

Zou,

Chen,

Zhan

et al. 2023

International Journal of Mining Science and Technology

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Effect of stress amplitude on mechanical and acoustic emission of sandstone under constant–cyclic loading

Cited by 6 publications

References 74 publications

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

Three-peak evolution characteristics of supporting stress on a super-long working face in a thick coal seam

Morphological evolution and flow conduction characteristics of fracture channels in fractured sandstone under cyclic loading and unloading

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