Investigation of the Effectiveness of a New Backfilling Method: “Multi-Arch Pier-Column”

Owing to the shortcomings of blindness and inaccuracy when backfilling in goafs based on key stratum theory, we propose “multi-arch pier-column” method. This method involves drilling holes at specific locations surface inject filling slurry materials into goaf separation area under stratum. allows broken gangue be cemented form a stone body, improve its overall strength. process, along with stratum, ensures that does not break, forming joint medium “separation body + backfilled pier-columns coal column”, which prevents new subsidence layer. Using Gaojialiang mine as an example, effects proposed controlling were determined using numerical simulation FLAC3D software. The results indicate this can effectively control ensure is within safe range. multi-arch pier-column utilises self-bearing capacity overburden structure greatly reduces workload cost for subsidence. At present, system backfill unexplored research.