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Three-dimensional void fraction evolution law and sensitivity analysis of mining-induced overburden based on
Zejun Li1, Nan Zhou2,3, YiZhu Lei4
1Key Laboratory of Deep Coal Resource Mining of the Ministry of Education, China University of Mining and Technology, Xuzhou, 221116, China.
Scientific Reports
|May 7, 2026
Summary
A new 3D dynamic void fraction (VF) model reveals how mining-induced overburden voids evolve over time. Key factors like mining height and strata distances significantly impact void evolution, crucial for hazard prevention.
Area of Science:
- Geological Engineering
- Mining Engineering
- Rock Mechanics
Background:
- Coal mining operations create voids in overlying strata, increasing the risk of geological hazards.
- Understanding the dynamic evolution of these mining-induced voids is critical for mitigating risks.
Purpose of the Study:
- To develop and validate a three-dimensional dynamic void fraction (VF) model to analyze overburden void evolution.
- To investigate the influence of key geological and mining parameters on void development.
Main Methods:
- Construction and verification of a 3D dynamic VF model based on the Bertalanffy time function.
- Proposal of four evaluation indicators: average VF for caving, fracture, and separation zones (AVF-CZ, AVF-FZ, AVF-SZ), and bulk average VF for the entire overburden (BAVF-EMO).
- Analysis of the impact of mining height, working face length, and distances of roof strata from the coal seam.
Main Results:
- Void fraction in the caving zone decreases with time, while other zones show increased VF, stabilizing after 80 days.
- Exceeding a 5m mining height significantly reduces AVF-CZ and BAVF-EMO.
- Increased distance between the sub-key stratum (SKS) and coal seam notably enhances AVF-FZ and AVF-SZ.
Conclusions:
- The developed model accurately simulates overburden void evolution under mining influences.
- Findings provide a theoretical foundation for optimizing backfilling strategies and managing mining-induced geological hazards.
- Understanding the relationship between geological structure and mining parameters is key to hazard control.
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