Arch Height Effect and Optimal Section Selection of Strata Behavior of Straight Wall Arch Roadway Under Mining Condition

In order to reduce roadway excavation and effectively control roadway surrounding rock deformation, different combinations of roadway width (4.5 m, 4.8 m, 5 m, 5.2 m), roadway height (3 m, 3.3 m, 3.5 m, 4 m), and arch height (0.3 m, 0.5 m, 0.8 m, 1 m) are selected. Through L₁₆(3⁴) three-factor four-level orthogonal test and numerical simulation, the surrounding rock deformation and plastic zone area evolution after roadway excavation are studied based on FLAC^3D. The results show that arch height is negatively correlated with plastic zone area in roadway roof surrounding rock and positively correlated with failure of roadway sides and corners. Further investigation finds the optimal combination to be roadway width 4.5 m, roadway height 3 m, and arch height 1 m. Compared with the original scheme, the new straight-wall arched section reduces plastic zone area by 35.07%, roof subsidence by 19.2% and side displacement by 22.4%. The optimized roadway section effectively reduces the failure range of surrounding rock plastic zone and contributes to long-term roadway stability.