Pre-presplitting and post-grouting reinforcement supporting structure and method for severe underground environment

The invention discloses a front-presplitting and rear-grouting reinforcement supporting structure and method for a severe underground environment, and belongs to the technical field of underground supporting. Pre-splitting holes and grouting holes are vertically formed in the periphery of a rock stratum space in a severe roof; hole protection steel pipes with single-side openings facing the rock stratum space are placed in the holes respectively, and a static expansion cracking agent is injected into the pre-cracking holes firstly, so that the severe roof is in a critical broken state; cement-based materials are injected through the grouting holes to fill the rock stratum fractures; after grouting is completed, the presplitting holes and the grouting holes are blocked; according to the method, the top plate is actively reinforced through human intervention, instability factors in the top plate are eliminated, so that the subsequent supporting work becomes simple and convenient, the problem that the pressure o