Mechanism of Water Inrush and Controlling Techniques for Fault-Traversing Roadways with Floor Heave Above Highly Confined Aquifers

Xu, Yong; Zhang, Ermeng; Luo, Yaqi; Zhao, Lin; Yi, Kang

doi:10.1007/s10230-020-00670-1

Cited by 26 publications

(8 citation statements)

References 10 publications

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“…In fact, p s is positive. If the result calculated by formula (8) or formula ( 9) is negative, it means that the roadway floor is in instability state under the current conditions. In conclusion, the condition of "sliding-rotating beam" motion is as follows: 6…”

Section: E Equilibrium Condition Of "Sliding-rotating Beam"mentioning

confidence: 99%

“…Floor heave is one of the focuses concerned by scholars at home and abroad [1][2][3][4][5][6][7]. A series of dynamic phenomena [8][9][10][11] such as roadway instability and floor water inrush are caused by floor heave, which not only affect mine ventilation, transportation, and pedestrians but also increase a lot of maintenance workload and mining costs [12,13].…”

Section: Introductionmentioning

confidence: 99%

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Stability Mechanism and Repair Method of U‐Shaped Steel Reverse Arch Support in Soft Floor Roadway

Wang

Chen

Zhang

et al. 2020

Advances in Civil Engineering

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This paper is aimed at the inverted arch support instability of track roadway with mining level +1100 m in Liuyuanzi Coal Mine. By means of field investigation, theoretical analysis, numerical calculation, and engineering practice, the instability reasons of inverted arch structure are expounded, the mechanical mechanism of instability of inverted arch structure is revealed, and the “sliding-rotating beam” for the instability of inverted arch structure is put forward. Based on Fenner’s formula and mechanics principle, the equilibrium equation of “sliding-rotating beam” is given. The results show the following: Firstly, the insufficient stiffness at the joint of the inverted arch structure and the U-shaped steel support on the floor is the key reason for the floor instability. Secondly, when the action stress of the “sliding-rotating beam” is less than the critical value, three kinds of instability modes of the inverted arch structure may occur, that is, sliding upward, rotating upward, or sliding-rotating upward. Each instability criterion and critical value are also different. Considering the axisymmetric condition, the critical value calculation formula of the three modes can be simplified into one formula. Thirdly, the equivalent friction factor restricts the stability of the “sliding-rotating beam,” and there is a “breaking point.” The relationship between the equivalent friction factor and the action stress of the “sliding-rotating beam” is “class hyperbola.” When the equivalent friction factor is greater than the “breaking point value,” the “sliding-rotating beam” may remain stable. Moreover, with the increase of equivalent friction factor, the action stress required for the stability of the “sliding-rotating beam” is smaller, and it tends to be more stable. The breaking point value of equivalent friction factor is 18.6. Finally, 36U-shaped steel round frame with bolt-mesh-shotcrete-combined support is applied to improve the equivalent friction factor and the foot stiffness of U-shaped support in roadway. After two months of on-site implementation, the floor heave was reduced by 69.1%. In conclusion, the theoretical analysis is correct and the control method is effective.

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Section: E Equilibrium Condition Of "Sliding-rotating Beam"mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stability Mechanism and Repair Method of U‐Shaped Steel Reverse Arch Support in Soft Floor Roadway

Wang

Chen

Zhang

et al. 2020

Advances in Civil Engineering

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“…Additionally, the law of the random horizontal movement of the thick loose layer under the influence of mining was summarized [3]. e coal seam overburden movement and the control mechanism of thin bedrock coal seams with thick loose layers were studied by various methods [4][5][6], and the results showed that the stability of the overburden mainly depended on the thickness of the bedrock and loose layers [7,8]. Engineering practice has shown that, at the working faces, a significant difference in the movement of the thick loose layer and the bedrock was observed [9].…”

Section: Introductionmentioning

confidence: 99%

Roof Failure Mechanism of Thin Bedrock Working Faces under Loading and Analysis Based on Microseismic Monitoring Technology

et al. 2022

Self Cite

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The resistance transfer coefficient of supports plays an important role in support selection in coal mines, which is the main factor in support crushing accidents. Based on the key layer theory, the formula for calculating the resistance transfer coefficient of supports under the load of a loose layer was deduced. The analysis of four working faces with thick loose layers and the corresponding mining pressure data were used to deduce the load transfer coefficients of the thick loose layers and ultimately illustrate the relationship between thick loose layers and different influencing factors. By using microseismic technology to monitor the process of roof failure in a thin bedrock working face with a thick loose layer during mining, the roof failure characteristics of a large-mining-height working face under the load of a thick loose layer were further verified. The results show that a thicker loose layer and thinner bedrock caused more of the load to transfer to the working face, the roof microseismic events were mainly concentrated in the range of 60 m to 75 m above the coal seam, and the most active events occurred during the square stage (the length of the working face’s goaf is equal to its width). The height of the water-conducting fracture zone was analyzed by microseismic data and then verified with theoretical calculations.

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“…Most of the abovementioned research focused on the failure characteristics, failure depth and range of the oor damage (Xu et al 2020;Zhang et al 2019), and the research methods adopted could not directly reproduce the characteristics of con ned water diversion and the failure process of the oor. To visualize the oor failure characteristics and the pattern of con ned water diversion in the mining process of the working face, this paper takes the II633 working face of the Hengyuan coal mine as the research object, uses a similar material simulation experimental method, and, with the help of an independently designed con ned water diversion monitoring system, visualizes the oor failure characteristics and the characteristics of con ned water diversion under the coupled effects of mining and con ned water.…”

Section: Introductionmentioning

confidence: 99%

Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

Wang

Yuan

Chen

et al. 2021

Preprint

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Coal mining in areas with deep confined water is very dangerous; to ensure safety, it is necessary to clarify the damage characteristics of the working face floor. To directly reflect the failure characteristics of the working face floor under the coupled effects of mining stress and confined water pressure, this study takes the II633 working face of the Hengyuan coal mine in the Huaibei mining area as the engineering background. With the use of a self-designed monitoring system for confined water diversion and a similar material simulation experimental method, the mining stress distribution patterns, the deformation and failure characteristics of the overburden, and the diversion characteristics of the confined water in the working face floor are studied. The combined use of a confined water loading system and a confined water lifting system can directly reproduce the floor confined water lifting characteristics affected by floor failure during coal mining. The results show that the floor undergoes three stages of deformation in the horizontal direction: premining stress concentration compression (10-15 m ahead of the working face), postmining floor pressure relief expansion, and roof collapse stress recovery (the distance of the lagging working face is 15-20 m). In the vertical direction, a soft rock layer blocks the continuous transfer of mining stress to deeper layers and produces an important cushioning effect. In the process of coal mining, shear cracks easily develop in the coal wall in front of and behind the working face. After the coal seam is excavated, the length of the fractures that develop in the model is 27 cm. The confined water loading system can visually reproduce the hydraulic characteristics of the confined water during the mining process; that is, the confined water easily bursts at the front and back ends of the coal wall in the goaf. The error, as determined by comparison between the field measurement and the theoretical calculation results, is only 0.617 m, verifying the reliability of the similar simulation method.

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Mechanism of Water Inrush and Controlling Techniques for Fault-Traversing Roadways with Floor Heave Above Highly Confined Aquifers

Cited by 26 publications

References 10 publications

Stability Mechanism and Repair Method of U‐Shaped Steel Reverse Arch Support in Soft Floor Roadway

Stability Mechanism and Repair Method of U‐Shaped Steel Reverse Arch Support in Soft Floor Roadway

Roof Failure Mechanism of Thin Bedrock Working Faces under Loading and Analysis Based on Microseismic Monitoring Technology

Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

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