Knothe模型改进及充填开采岩层移动动态过程分析

Improvement of Knothe model and analysis on dynamic evolution law of strata movement in fill mining

Knothe模型是岩层移动动态预测最常用的时间函数模型,但该模型与岩层移动动态演化过程客观规律并不完全相符.通过分析Knothe模型岩层移动预测缺陷,增加表征时间影响函数变化和岩层移动非线性特征的双参数,建立了Knothe时间函数改进模型;基于弹性力学理论,建立充填开采岩层移动的小挠度弯曲变形薄板模型;将Knothe函数改进模型与建立的充填开采岩层移动模型相结合,构建了岩层随时间移动的动态演化过程函数表达式,并将演化过程划分为初始期、活跃期及衰退期.以新汶矿区翟镇煤矿2205工作面矸石充填开采实测数据为样本,开展了充填开采岩层移动动态过程实例验证分析.结果表明:在第22.9个月,地表最大下沉点的下沉速度达10.526mm/月;岩层总移动时间为38.9个月,其中初始期为20.5月、活跃期为5.1月、衰退期为13.3月.基于Knothe改进模型构建的岩层移动动态演化过程的函数表达式能够更客观真实地反映出岩层下沉量、下沉速度、下沉加速度的客观变化规律.

Knothe time function model is the most commonly used models in the dynamic prediction of stratum movement.However,this model is incompletely consistent with the objective law of the dynamic evolution of the stratum movement.Based on the analysis of this defect,the two-parameter which represents the effect of time on function change and characterizes the nonlinear stratum movement was added and the improved Knothe time function was established.The sheet model of the bending deformation of small deflection in stratum movement when using the filling mining system was built on the basis of the elasticity theory.The improved Knothe time function model was combined with the strata movement model in the filling mining system,the functional expression of dynamic evolution of stratum movement as time goes was established and this evolutionary process was classified as the initial period,the active period and the declining period.The case analysis of the dynamic process of stratum movement in the filling system was carried out based on the measured data of backfilling method with re-fuse of No.2205 working face in Zhai town coal mine,Xinwen mining area.The results show that the speed of the maximum point of surface subsidence is 10.526 mm per month,the total time of stratum movement is 38.9months,and the initial period,the active period and the declining period are 20.5 months,5.1 months and 13.3 months,respectively.It can be seen clearly that this function expression can objectively reflect the quantity of stratum subsidence,the rate of subsidence and the objective law of the change of the subsidence acceleration.