To determine the impact of influencing factors on unsupported roof stability in coal mine roadway, a mechanical model of the unsupported roof was built. FLAC 3D numerical simulation was utilized to study the stability of the unsupported roof under the influence of the depth of the roadway, the thickness of the roof, and the unsupported‐support distance. In view of the key influencing factors, the geological conditions of the site, and the relationship between the tensile stress and tensile strength of the unsupported roof, the maximum unsupported roof distance during roadway excavation was determined. Considering the surplus safety factor of the unsupported roof, the reasonable unsupported roof distance during the excavation of roadway 150802 was finally determined to be 2.08 m. The comprehensive roadway excavation speed increased by 62.7%, achieving a monthly progress over 500 m.

In order to study the deflection and failure characteristics of the goaf roof, a mechanical model of the goaf thin plate is established and the deflection expression of the goaf roof is obtained. The results show the following: (1) under the action of single factor, the roof deflection is more sensitive to the interaction of unsupported roof distance and load, but less sensitive to the support force. (2) The influence degree of each factor on the deflection of the thin plate in the unsupported top area is as follows: unsupported roof distance and load interaction > unsupported roof distance and supporting force > supporting force and load. (3) The roof bending deformation is slow when the unsupported roof distance is within 0–2.3 m. When the vacant distance of the roof is more than 2.3 m, the bending deformation of the roof is accelerated. Using FLAC3D numerical simulation software, the distribution of vertical stress and displacement under different space distances is analyzed and the reasonable space distance is 2.0 m. Through the application of 150802 machine roadway in Liuzhuang coal mine, the driving speed of the coal roadway is improved and the monthly footage of coal roadway reaches 506 m.