Abstract
To investigate the feasibility and safety control technologies for main roadway excavation through the Dashuigou protective coal pillar area, an elastoplastic mechanical model was used to characterize the roadway‐induced expansion of the plastic zone and determine the width of the residual elastic core. A probability integral method was applied to predict overburden movement and surface deformation caused by roadway excavation. Three‐dimensional FLAC3D simulations were subsequently conducted to examine stress redistribution, displacement development, and plastic‐zone evolution around the roadways. Field monitoring was also performed to verify the analytical and numerical results. The results show that the maximum plastic‐zone width on either side of the protective coal pillar is approximately 0.71 m, whereas the minimum elastic‐core width remains 21.95 m. The estimated pillar load is approximately 3.27 MPa, which is substantially lower than the average failure strength of the coal pillar (10 MPa). The predicted maximum surface subsidence is approximately 28 mm, with a maximum tilt of 0.4 mm/m, a maximum curvature of 0.1 × 10
−4
mm/m
2
, and a maximum horizontal displacement of 12 mm. All these indices remain below the allowable limits specified in the relevant regulations. The numerical simulations indicate a peak stress of approximately 3.9 MPa at the roadway ribs, a maximum roof displacement of about 60 mm, and a plastic‐zone depth of 1.2–2.5 m. Field measurements further show that the roof‐to‐floor convergence of the roadways in the 5‐1 and 5‐2 coal seams stabilizes at approximately 49.5 and 59 mm, respectively. Roof separation remains limited, and the surrounding‐rock deformation gradually approaches a stable state during the later stage of roadway development. These observations agree well with the analytical predictions and numerical simulations. The results may provide a useful reference for roadway engineering in deferred‐mining zones under surface‐water bodies under comparable geological and hydrogeological conditions.