Abstract:
Aiming at the problems of support overload and surrounding rock instability caused by the mutation of roof integrity during the 15302 fully mechanized caving face passing through the NDX24 collapse column, based on the theory of "structural mutation - stress response", a support parameter optimization path with the geological response characteristics of the rock mass as the core is constructed. Through drilling and core extraction, wave velocity testing, and GSI graded analysis, the binary structure of "column edge fracture - column core looseness" is identified, and the initial support value is determined by combining 3D primary selection matrix; FLAC
3D numerical simulation is adopted to design a orthogonal test of "four factor three-level", the combination of support parameters is optimized and selected through entropy weight - TOPSIS model. The results show that the optimized combination (180 kN pretension, 8.0 m anchorage, 1.0 m row spacing, 15 mm yielding) can reduce the roof subsidence and the displacement amount of two sides by 30.8% and 28.1%, respectively, and reduce the excavation cost by 9.6% per ton of coal. This research provides a quantitative and scalable optimization method and on-site verification basis for the support design of collapsed column areas.