The migration law of overlying strata on working face is of great significance for safe mining of working face. In this paper, theoretical calculation, numerical simulation, and similar simulation are used to study the distribution characteristics, migration, and fracture law of key strata in the overlying strata of 130204 working face of Y.C.W coal mine and the relationship between the development height of water flowing fractured zone and the spatial position of weak aquifer. The theoretical calculation results show that there are “one main two sub” key strata in the overlying strata of 130204 working face, which play an important role in controlling rock movement. Numerical simulation and similar simulation results show that the first weighting step distance of the direct roof of 130204 working face is about 30-40 m. The initial weighting interval of the basic roof of the working face is about 70-80 m, and the periodic weighting interval is about 23.5-25 m. After the first weighting and multiple periodic weighting of the basic roof of the working face, the first subcritical layer is located in the caving zone, the second subcritical layer is located in the fracture zone, and the main key layer is finally located in the bending subsidence zone. The final height of the caving zone of the overlying strata is about 24 m, and the height of the water flowing fractured zone is about 130 m. Since the water-conducting fractured zone is connected and passes through the second subcritical layer with weak water-bearing property, it is possible for the water permeability accident of the working face. Therefore, in order to ensure the safety of the working face, the water should be detected and released in advance during the mining of the working face.

The original rock stress field is mainly divided into the σHZ-dominant stress field, the σZ-dominant stress field, and the σH-dominant stress field. Via theoretical analysis, the plastic zone morphology and the orientation of roadway surrounding rock under a three-dimensional stress field are studied in depth, and the theory is verified by numerical simulation. The results show that in the σHZ-dominant stress field, the plastic failure mode changes from elliptical to quasi-circular to butterfly, and the optimized angle range of the roadway orientation is determined by three principal stresses. In the σZ-dominant stress field, the shape of the plastic zone transforms from butterfly to ellipse, the optimized angle range of the roadway orientation is 50–90°, and the butterfly hidden danger zone is in the 0–50° range. In the σH-dominated stress field, the shape of the plastic zone transits from ellipse to butterfly. The optimized angle range of the roadway orientation is 0–40°, and 50–90° is the butterfly hidden danger zone.

Underground reservoir water storage technology has become one important way to achieve efficient coal mining and water resource protection in the western mining areas of China, and the width of coal pillar dams is an important factor affecting the safe operation of underground reservoirs. In order to study the limitations on the reasonable size of a coal pillar dam, Daliuta Mine was selected as the engineering background and a theoretical formula for the reasonable width of a coal pillar dam was proposed. By combining theoretical analysis with numerical simulation analysis, the main influencing factors of the coal pillar dam were compared and analyzed. The research results indicated that changes in the mining height and coal parameters can cause a sharp change in the width of the plastic zone of the dam body. Then, mine water will have an impact on the width of the plastic zone and the width of the elastic core. Moreover, when the width of the coal pillar is smaller than the theoretically calculated width of the coal pillar dam body, the deviator stress and vertical stress inside the dam will significantly increase, and the plastic zone of the dam will significantly expand.