A Disturbed Voussoir Beam Structure Mechanical Model and Its Application in Feasibility Determination of Upward Mining

Abstract

China is endowed with a large quantity of residual coal resources that require upward mining. The stability of interburden strata structures and accurate determination are crucial for safe mining. Therefore, we established a mechanical model of disturbed voussoir beam structures of interburden strata in upward mining. The model was solved, and stability analysis and instability mechanism analysis were conducted. Based on this model, a new method for determining the feasibility of upward mining was proposed and applied to the upward mining of coal seam No. 7 in Baijiazhuang Coal Mine. A physical simulation experiment and numerical simulation were conducted to validate the method. Through research, it was found that the model had two instability mechanisms: rotation instability and sliding instability. When the disturbance load crossed the critical block of the structures, the model was most likely to experience sliding instability. When the disturbance load acted entirely on the critical block, rotation instability was more likely to occur. The result of the determination, performed using the new method, showed that there was no rotation instability or sliding instability in the interburden strata structures of coal seam No. 7, indicating that the coal seam could be mined upward. This result was consistent with the determinations using the statistical method, “three-zone” method, and balanced surrounding rock method. Physical and numerical simulations revealed that the upward mining of coal seam No. 7 caused the subsidence, rotation, and separation compaction of the interburden strata structures but that the structures remained stable. The results indicate that the proposed model and method have accuracy and applicability, being able to guide the practical feasibility determination of upward mining.

Quantitative Evaluation Method and Response Mechanism of Shallow Groundwater in Multi-Mine Mining of “Soil–Rock” Composite Water-Resisting Strata

“…Mastering the evolution law of shallow groundwater is an important prerequisite for protecting shallow water systems [24][25][26]. This study aimed to reveal the evolution law and redistribution characteristics of shallow water flow fields in single/multi-mining units of different sizes at the mining scale [27,28].…”

Calculation Method of Support Load Zoning and Mechanism of Mine Pressure Behavior in Upward Mining Face across Half of the Goaf along the Panel Direction

“…Studies indicate that a prerequisite for upward mining is to extract the lower coal seam without compromising the integrity and continuity of the overlying upper coal seam [27][28][29][30][31][32][33]. The feasibility of upward mining in the 1515 mining face was assessed by three methods, namely, the ratio discrimination method, the rock balance discrimination method, and the discrimination method of "three zones" [34].…”

The failure behavior of coal-rock combined body under compression-shear loading

“…Coal resources play a pivotal role as a strategic safeguard for China's primary energy supply, with coal reserves buried at depths exceeding 1 km constituting approximately 75% of the untapped reserves. [1][2][3][4][5] As the demand for coal resources continues to surge, the depletion of shallow coal reserves is accelerating, making deep mining an increasingly prevalent practice. Nevertheless, this shift to deep mining is not without its challenges, as it entails facing various hazards, including rock bursts, coal and gas outbursts, roof collapse, and water inrush incidents.…”