Abstract:
In view of the current research status that relatively few prediction models exist for surface subsidence velocity induced by full strike mining, a calculation method for the maximum surface subsidence velocity in full strike mining was proposed based on the extreme value principle with the improvement of the Knothe time function model, and a comparative analysis was conducted on its advantages over the existing theoretical and empirical calculation methods. Subsequently, combined with the characteristic that the surface subsidence velocity curve approximately follows a normal distribution, a prediction model for surface subsidence velocity in full strike mining was established, and the determination method for model parameters was given. Finally, the accuracy and rationality of the prediction model were verified using the field monitoring data of surface subsidence velocity from full strike mining working faces in a coal mine in Huainan and Bulianta Coal Mine. The results show that the average errors between the theoretical calculated values and the measured values of the maximum surface subsidence velocity in full strike mining of the two mining areas are only 1.01 mm/d and 3.52 mm/d, respectively, which verifies the accuracy of the proposed calculation method for the maximum surface subsidence velocity. The surface subsidence velocity curves predicted by the model for the two mining areas are basically consistent with the measured curves, with the average standard deviations of only 1.7 mm/d and 2.2 mm/d, respectively, which further verifies the accuracy and rationality of the theoretical model. The measured curves are basically consistent with the theoretical curves on the side of the open-off cut, while the predicted values are higher than the field monitoring values on the side of the final mining line of the working face. This phenomenon is attributed to two aspects: on the one hand, the mining influence on the side of the final mining line has a lag effect, so that when mining reaches the working face position, the mining influence is not fully transmitted to the surface, and the intensity of surface subsidence is not fully manifested; on the other hand, the surface subsidence velocity curve does not strictly conform to a normal distribution.