Model Optimization Of Weibull Time Function And Dynamic Prediction Of Mining Subsidence

As one of the main energy resources used in China,coal resources will cause varying degrees of damage to ground buildings,roads and farmland in the mining process,and seriously affect the survival of human beings and sustainable development of society.Mining subsidence estimated are divided into static and dynamic is expected,the surface movement deformation caused by mining static,expects to get stop deformation after the final state of deformation value is important,but in industrial production,the dynamic subsidence of surface is obtained by dynamic is expected to change rule is more close to the actual,in the process of coal mining,accurately grasp the dynamic deformation information of the mining area,It has important practical significance for protecting ground buildings and rationally utilizing land resources in subsidence area.The key of dynamic prediction model is time function.Based on probability integral theory,this paper optimizes the Weibull time function model with good completeness,and builds the dynamic prediction model of trending main section and trending main section under limited mining conditions.The main work and innovation points of this paper are as follows:(1)Summarizes the theory of mining subsidence,dynamic expected time and function of the research status at home and abroad,describes in detail is often used in the structure of mining subsidence dynamic time function is expected,parameters,characteristics,and the model features of ideal time function as reference,comparison and analysis of each function model in the dynamic subsidence is expected to work the advantages and disadvantages and applicability.(2)The Weibull time function model is optimized using the piecewise function idea to improve the dynamic prediction accuracy of the time function model.The main problems existing in dynamic prediction of Weibull time function model are summarized: First,the subsidence predicted by Weibull time function at the time of maximum subsidence velocity τat the cut-off point is not equal to half of the maximum subsidence in the final state,which will cause great prediction deviation;Second,in the initial stage of mobile deformation,the slope of the subsidence curve predicted by Weibull time function increases too fast,which affects the universality of the function for dynamic prediction.In order to solve the above problems,this paper optimizes the Weibull time function model and establishes a piecewise Weibull time function model.Experimental results show that the optimized time function still maintains good space-time completeness,and the sink of τ time is consistent with the theoretical value by changing the parameter value.In addition,the rate of slope change of sinking curve is obviously slowed down in the initial stage,which effectively solves the original problem.This paper introduces several methods of calculating the maximum sinking velocity time τ,the time influence coefficient C and the power index parameter K,studies the relation between τ and x(the distance from open incision)by regression analysis method,and obtains the corresponding quadratic nonlinear regression equation.(3)Based on the optimized Weibull time function model and the probability integral theory,this paper analyzes the dynamic superposition principle of surface movement and deformation in the process of coal seam advancing,studies the division method of mining units,and deduces the time function calculation formula corresponding to n independent units in dynamic mining.Finally,the dynamic prediction models of strike main section and dip main section under the condition of limited mining are constructed,and the rationality of the model is proved by the measured data.