The stress distribution of a hinged arch, which is formed by the initially-fracturing main roof, is analyzed, and a new formulation for horizontal thrust is developed by adopting an exponential law. Based on strict geometric transformation, the amount of deformation and subsidence are obtained. The results are validated by comparing the calculated results of the proposed formulation to the numerical results and field observations. The new formulation for thrust is applied to evaluate the structural stability. It is found that for shallow super-long mining face, when the angle of rotation is less than 3°, the thrust of the block with fragmentation i >0.4 increases slightly with the length of mining face and the angle of rotation, and the block fails to destablize due to sliding when i<0.45; if i≤0.3 the thrust increases significantly; the block is prone to fail due to overhigh thrust when the angle of rotation is more than 6°; the stable range for rotation by the proposed formulation is 12%, at least larger than the traditional range.