Theoretical analysis of the secondary development of mining-induced surface cracks in the Ordos region

Prior studies have indicated that mining-induced surface dynamic cracks in eastern China only undergo one "expanding-closure" development cycle. However, field measurements from the Bulianta mines of northwestern China demonstrated that ground dynamic cracks in the Ordos region went through two "expanding-closure" cycle. Using in situ measurement data and theoretical analysis, we find that the strata control theory cannot reasonably explain this special phenomenon. In this paper, we propose a novel explanation from the perspective of soil mechanics. A comparison of two field examples in eastern and northwestern China demonstrates that our theoretical explanation is in agreement with in situ observations and therefore is a reasonable interpretation for the secondary development of ground dynamic cracks in the Bulianta mines. This study provides a theoretical basis for the mechanism of mining-induced ground dynamic cracks.