AUTHOR=Chen Hanxin , Luan Mengying , Xue Mei , Wang Mingquan , Tian Hailang , Qu Yinghao , Yuan Qiang , Zhang Mingtian 

TITLE=Study on structural evolution law of overlying rock mass in fully mechanized top-coal caving face under open-pit slope with extremely thick and hard overburden

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 13 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2025.1609397

DOI=10.3389/feart.2025.1609397

ISSN=2296-6463

ABSTRACT=Analyzing overburden movement, surface deformation and fracturing in mines with extremely thick, hard cover is critical for coal mine safety. In this context, the present study examines the 021N2 fully-mechanized top-coal caving face beneath an open-pit slope with extremely thick, hard overburden, developing structural-mechanics models and performing PFC-2D numerical simulations to investigate the structural evolution of the overlying rock mass. The simulations reveal that vertical displacement dominates the slope’s post-mining deformation, and that a force-chain arch forms above the goaf with associated stress fracturing and redistribution. In addition, mining-induced surface fissures create significant air leakage into the goaf, posing a high risk of spontaneous combustion. These findings provide a theoretical basis and technical guidance for controlling thick-overburden caving faces under open-pit slopes, thereby informing safer mining operations and engineering practice in similar contexts.