In　deep　rock　blasting　excavation,　high　in-situ　stress　often　leads　to　difficulties　in　presplitting　and　poor　contour　quality,　which　affect　engineering　safety.　To　counteract　the　inhibitory　effect　of　in-situ　stress,　water-coupled　charge　can　be　used　due　to　its　high　energy　transfer　efficiency.　In　this　study,　an　improved　calculation　model　of　crack　propagation　driven　by　the　quasi-static　pressure　of　explosion　gas–water　is　proposed　to　analyze　the　crack　propagation　and　coalescence　under　in-situ　stress.　Following,　a　three-hole　numerical　model　is　established　to　verify　the　theoretical　results　and　investigate　the　inter-hole　crack　characteristics.　The　results　show　that　the　in-situ　stress　inhibits　presplitting,　while　water　is　more　conducive　to　presplitting　than　air,　especially　under　high　in-situ　stress　and　low　rock　fracture　toughness.　The　hole　spacing　and　decoupling　ratio　should　be　reduced　under　high　in-situ　stress.　Using　water　as　the　filling　medium　and　aligning　holes　with　the　maximum　principal　stress　significantly　enhance　the　directional　effect　and　are　beneficial　to　rock　damage　control.　Finally,　optimization　schemes　are　verified　based　on　the　excavation　of　deep-buried　stopes.　Evaluations　of　the　3D-scanned　contour　reveal　that　water　and　parallel　layout　increase　the　hole　spacing　by　20　%　and　50　%　respectively,　while　maintaining　or　even　improving　the　contour　quality.　©　2025　Elsevier　Ltd