Fault-influenced overburden deformation in a steeply dipping submarine orebody

Abstract

Seabed mining operations have been found to induce significant movement and deformation in overlying rock strata, posing serious threats to mining safety. The presence of geological faults further complicates these deformation patterns. This study utilized geophysical surveys and the continuum-based discrete element method (CDEM) to investigate how fault activity influences rock deformation and failure. The results demonstrate that: 1) Acting in mechanically weak zones, faults exerted a pronounced barrier effect on deformation propagation and stress redistribution within the surrounding rock, leading to markedly divergent displacement patterns on either side of the fault plane. Comparative analyses between single-fault and double-fault models revealed an 18%–22% expansion of the damage zone under the latter, together with significantly intensified deformation and failure; 2) The double-fault model exhibited a larger maximum cumulative vertical displacement and a spatial shift in the location of peak deformation, thereby posing a heightened threat to mine safety; 3) Acting in an orebody substitute, backfill effectively constrained surrounding rock deformation, enhanced its load-bearing capacity, and delayed the overburden subsidence. Nevertheless, backfill only reduced the amplitude of deformation; it could not entirely prevent settlement. These findings provide essential theoretical insights and foundational knowledge for safer submarine mining practices.

Keywords

submarine mining / steeply inclined ore body / fault effect / overburden deformation / discrete element method of continuum mechanics

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