The Study Of Mining Subsidence Dynamic Prediction Model And Its Parameters

Mining subsidence is a complex process which changes with time and space;in order to explore the mechanism of mining subsidence,reduce the influence of mining subsidence on environment,it is important to study the dynamic procedure of surface movement deformation caused by underground mining.This article selected three working face in Huainan&Huaibei mining area as experimental faces.Analysis the rule of dynamic subsidence with measured data of surface movement deformation observation.The process of surface subsidence couble been divided into four stages according to the characteristics surface subsidence speed:pre-mining stable stage,acceleration subsidence stage,deceleration subsidence stage and after mining stable stage.The characteristic and the proportion of the total subsidence time of each stagr are related to the geological and mining conditions and the relative position of surface point in working face.Derivating and analysising the Knothe time function which is current most widely dynamic prediction model in Mining subsidence areas.Calculating the parameters of Knothe time function using the measured from surface movement deformation observation,inversion the surface subsidence process and comparing with the measured values.The results show that:Knothe time function has certain defects in simulating the surface subsidence speed,using this model to predicte the sinking process of the surface dynamic coulde cause greater error.Improved Knothe time function can overcome the defect of original Knothe time function in describing the surface subsidence speed.According to the defect of Knothe time function,this paper adds a new parameter ?to the Knothe time function,establishe the imoroved Knothe time function with piecewise function which r is discontinuity point,and predicte or inverse dynamic process of surface subsidence with higher accuracy.Analysis the parameters in the improved Knothe time function,the finally surface subsidence W0 control the upper and lower boundary of function;time factor influence coefficient C and the time of maximum sinking speed r change the configuration of function curve.Study the calculating method of each parameter:the finally surface subsidence WO could acquired with probability integral method model or D-InSAR technology;time factor influence coefficient C could be calculated with observation experimental data or calculating its value scope according to working face geological and mining conditions;the time of maximum sinking speed r could be calculated by maximum subsidence velocity lag angle.Calculating the improve Knothe time function parameters with surface movement observation station measured data.Establishing the dynamic prediction model of surface subsidence with calculated parameters,compared the expected values with the measured values and analysis the precision of improved Knothe time function,Results indicate that improved Knothe time function could simulate the dynamic process of the surface subsidence of mining subsidence with higher accuracy.In the end,exploring the application of improved Knothe time function with the prediction of scope of the surface water and building and construction damaged condition.