Determination of large-height support resistance based on multi-factor analysis

In response to challenge of adaptability of support and working resistance in large-height working face,the “cantilever beam-sandwich-voussoir beam” structure model is established,and the preliminary scheme of support re- sistance is calculated,which is verified by both numerical simulation and large-scale physical modeling. The study shows that the working resistance should meet the supporting demands of roof and rib,and keep itself with good posi- tion. The working resistance consists of two parts:one part is to bear the weight of cantilever beam due to breakage of key strata in caving zone;and the other is to balance the voussoir beam structure located in lower strata of fissure zone. When the working resistance is lower than 10 000 kN,the support operates at full capacity,and the deformation of sur- rounding rock increases distinctly;when the rated resistance higher than 11 000 kN,the indicator decreases distinctly. And the reasonable working resistance is determined to be 12 000 kN,which is verified feasible by the production practice. In mining practice,the terminal resistance is 8 340-10 247 kN and the percentage of safety valve opening is below 5% ,so the scheme can meet the production requirements.