Study On Surface Dynamic Subsidence Prediction Method Based On Negative Exponential Method And Weibull Time Sequence Function

The movement and deformation of overlying strata and surface induced by underground mining is a complex and nonlinear process with time and space. As the working surface advancing, the construction of surface subsidence area will experience a movement and deformation process from dynamic to static, although the impact of dynamic deformation is temporary, once the structure of the building is destroyed, its security will be very difficult to guarantee. Therefore, it has important theoretical value and practical guiding significance for the accurate prediction of surface dynamic movement and deformation in mining process to prevent and mitigate the mining damage and to ensure the safe operation of the ground construction.On the basis of comprehensive analysis of domestic and foreign research status of dynamic prediction theories and methods of mining subsidence, this paper studies and summarizes dynamic prediction methods of mining subsidence from various aspects of measured subsidence data, physical mechanics, numerical calculation; it points out that Weibull time sequence function can accurately fit surface subsidence process; at the same time, the derivation process and the physical meaning of the parameters of the negative exponential prediction method of mining subsidence are further studied. According to the general form of the main section of the dynamic subsidence model, Weibull time sequence function and negative exponential function are combined to establish the surface dynamic prediction model based on Weibull time sequence function and negative exponential prediction method, and the prediction model is verified and analyzed. Concrete results are as follows:(1) The negative exponential function method of mining subsidence is suitable for the prediction of surface movement and deformation in the face of the approximately rectangular working surface, the selection of prediction parameters are closely related to the nature of overlying strata and surface measured subsidence data, the prediction results can reflect the real situation of surface subsidence, and the method has more flexibility for showing the actual subsidence curve of no antisymmetry relative to the inflection point.(2) While describing the process of dynamic subsidence of the observation points in the ground, the Weibull time sequence function can well fit the subsidence-time(w-t) curve, and the velocity time(v-t) curve and acceleration time(a-t) curve that are deduced by the subsidence-time curve can also meet the physical process of surface subsidence changes with time effectively, and the model parameters are obtained by using the least square fitting method.(3) Based on the Weibull time sequence function and negative exponential function, the prediction model of surface dynamic movement and deformation(including subsidence, tilt, curvature, horizontal displacement and strain) of the trend and tendency main section of surface subsidence area are established under the subcritical and critical mining conditions, and the model is deeply analyzed.(4) The surface dynamic subsidence prediction model based on Weibull time sequence function and negative exponential function is verified and analyzed, the prediction relative error is within the tolerance range by comparing and analyzing prediction results and surface measured subsidence data, and it proves out that the model is reasonable and effective, and provides a reference for the surface dynamic subsidence prediction.