Abstract
Abstract
To address severe surrounding-rock deformation in large-span dynamic-pressure roadways under shallow-buried closely-spaced coal seam mining, the No. 9 seam 914 panel entries of a typical mine are taken as the prototype. A combined analytical–numerical–similarity-test and in-situ monitoring framework is employed to investigate the evolution of mining-induced stress, the surrounding-rock deformation mechanism, and dual-arch synergetic support. (1) The lateral abutment pressure exhibits a single-peak distribution with
σ
max
≈ 12MPa at 16 m from the goaf boundary; advance abutment pressure peaks 14–20 m ahead of the coal wall. (2) Within the Rudnicki–Rice strain-localization framework, a rigorous displacement-vector-direction mutation criterion is derived, yielding \({\theta _c} \approx {27^^\circ }\) and a stress threshold of 15 MPa. (3) A "failure-depth / arch-stiffness matching" principle \({K_i}/{K_o} \in [0.1,0.3]\) is introduced to construct a "bolt-mesh inner arch + anchor-cable outer arch" synergetic bearing structure. (4) Six-month monitoring at 15 stations shows that the optimized scheme reduces maximum roof subsidence from 236 mm to 89 mm (-62.3%, p < 0.001), two-rib convergence from 178 mm to 75 mm (-57.9%) and deep roof bed-separation from 32 mm to 6 mm (-81.3%).