There is a layer of the unconsolidated confined aquifer (UCA) made of non-cemented sand and grit on the bed of Quaternary thick topsoil in many coal mines in east and north China. Existing on the bedrock of coal measures, it poses a serious threat to coal mine safety. Worse, it caused many supports crushing and water inrush disasters (SCWIDs) and resulted in significant economic losses. Aiming at the above problems, this paper adopts a simulation experiment, field measurement, engineering detection, and theoretical analysis to conduct the research. The research reveals the overburden’s destructive rules during mining under UCA. The results indicate that UCA plays an important role in the process of load transfer due to its mobility and replenishment in time. When mining close to the aquifer, the load transfer of aquifer leads to overburden breaking entirely and sliding instability of the bond-beam structure, then, the water flowing fractured zone develops rapidly and connects the aquifer, which is the fundamental reason for SCWID under the UCA. Based on the mechanism of SCWID, a prediction method of support crushing and water inrush hazard zones was put forward. Artificial pre-split blasting based on the location of a key stratum was applied to prevent SCWID. The proposed methods have been used in 7₁31 working face and safe mining was achieved.

Traditional physical similarity simulation methods struggle to replicate the cumulative unloading–expansion effect in overburden, particularly due to inherent limitations in representing the bulking–compaction behavior of fractured rock masses in the caving zone. This significantly hinders a deeper understanding of overburden movement mechanisms. To address this technical challenge, this study innovatively proposes an experimental method designed to simulate the bulking–compaction process of rock masses in the caving zone. The method employs a composite of EPE and PP sheets. Through systematic uniaxial compression tests and orthogonal experimental design optimization, an optimal material mix ratio with superior performance was identified. Its stress–strain behavior was systematically analyzed, and its feasibility was comprehensively verified from the perspective of the synergistic evolution of displacement and stress fields. The results demonstrate that the stress–strain response of the new similar simulation material (SSM) aligns highly with the Salamon model. Furthermore, its load-bearing capacity exhibits a non-linear strengthening characteristic with increasing EPE thickness. Physical simulation validation tests, based on the engineering context of the Shilawusu Coal Mine, showed that all the relative error parameters were strictly controlled within 12%. The overall accuracy was significantly superior to existing simulation methods, achieving a substantial reduction in prediction errors for key parameters.