Dynamic Evolution Law of Overburden Rock in Shallow‐Buried Super‐High Fully Mechanized Working Face and Determination of Support Strength

Abstract

The objective of this study was to reveal the law of overburden movement and stress evolution during the mining of super-high fully mechanized mining faces. Based on the 12401 fully mechanized mining face of Shangwan Coal Mine in Shendong, this study conducted research and analysis using the methods of similarity simulation experiment, numerical simulation, and field measurement. The results showed that the maximum and minimum principal stresses in the coal seam in front of the working face are concentrated with the advance of the working face. The degree of stress concentration increases with the increase in the advancing range, and the concentration degree of the maximum principal stress and the change gradient is greater than that of the minimum principal stress. But the range of the peak lead coal wall is lower than that of the minimum principal stress of the peak lead coal wall. The phenomenon of stress recovery exists in the goaf. With the increase in the advancing range of the working face, the degree of stress recovery gradually increases, and the degree of maximum principal stress recovery is higher than that of the minimum principal stress recovery. The large fractures observed near the working face are closely related to the underground pressure, relatively large fractures appear on the surface, and the fractures become narrower near the two pathways. Only caving and fissure zones exist in the thin bedrock overburden, and the bending subsidence zone changes with the bedrock thickness. The support strength of the hydraulic support should not be less than 1.47 MPa. This research on the overburden movement and stress evolution law of a super-high fully mechanized mining face can provide theoretical guidance for the exploitation and utilization of extrathick coal seam resources. It has broad engineering prospects.

Experimental Study on Ratio Optimization of Similar Materials for Underground Mining of Shendong Coalfield: A Case Study of Shangwan Coal Mine

“…The graph presented in Figure 14 displays the predicted periodic pressure step distance of 12,401 working face in Shangwan coal mine in comparison to the other literature. It is evident that the data obtained in this study closely align with the results from the previous literature, providing evidence for the accuracy of the similar material ratio utilized in this paper [38][39][40][41]. It is important to note that this study has some limitations.…”

Study on Dynamic Evolution of Overburden Rock Movement and Mining-Induced Stress of Ultra-high Working Face

“…Afected by the coal seam excavation, the magnitude and direction of the maximum principal stress of each rock stratum will change. Te distribution characteristics of the maximum principal stress of the coal seam under diferent advancing distances are shown in Figure 3 [30]. With the continuous advance of the working face, the classic law of frst increasing and then decreasing the in-situ rock stress is formed in the front, rear, and both sides of the goaf.…”

“…When the main roof is broken, the stress concentration phenomenon above the coal wall is weakened, the stress concentration value and infuence range are reduced, and the stress concentration phenomenon around the goaf changes little. Te distribution characteristics of the minimum principal stress under diferent propulsion distances are shown in Figure 4 [30].…”

Synergy Prediction Model of Information Entropy Based on Zone Safety Degree and Stope Roof Weighting Step Analysis

“…Li et al [6] employed the method of physical similarity modeling and field observation to study the fracturing migration law of the overlying rock during the mining process of extremely dense coal seam. Liu et al [7] used the similar simulation test, the numerical simulation, the field measurement and other methods to Axioms 2023, 12, 892 2 of 14 investigate the overburden rock movement and stress evolution law of the 12,401 working face in the Shangwan Coal Mine of Guoneng Shendong Coal Group Co., Ltd. in the Inner Mongolia Autonomous Region of China, which has provided the theoretical guidance for the development and utilization of extra-thick coal seam resources. Guo et al [8] took the geological conditions and practical mining conditions of the 21,129 working face of Tucheng Coal Mine in China's Guizhou Province as the engineering background, and used the method of combination of similar simulation test and field measurement to study the evolution law of the stope fracture field, the stress variation trend of the roof fault and the migration characteristics of the overlying rock in the double-fault recovery process.…”