修正的Knothe沉陷模型及FLAC^(3D)模拟开采验证

Modified Knothe Subsidence Model and Mining Verified by FLAC^(3D) Simulation

针对原Knothe地表沉陷的时间函数模型与地表观测点下沉速度曲线不吻合的缺陷,采用数学分析的方法,修正了Knothe模型。修正的模型不但能较好地拟合地表沉陷观测点下沉的位移序列,而且从观测点下沉速度、加速度的变化方面也符合地下煤层长壁工作面开采过程中上覆岩层移动的物理过程,能较好地描述地表观测点下沉的3个阶段即逐渐开始阶段、快速发展阶段和缓慢衰减终止阶段的非线性特征。验证这一模型需要大量的观测数据,为克服进行大量的沉陷观测所需的人力和物力上的困难,采用FLAC^(3D)软件模拟的煤层地下开采过程,并在模型的上表面经过开采中心点的走向和倾向剖面线上共布置了36个地表下沉和下沉速度的监测点,监测了模拟开采过程中地表的移动过程;模拟完成后,各监测点的下沉及下沉速度与计算步数之间的关系曲线与修正的Knothe模型曲线的形态特征相符,说明模拟开采过程可行,进一步验证了修正的Knothe地表沉陷的时间函数模型可拟合地表观测点下沉的动态过程曲线。

To inconsistent disadvantage between original Knothe surface subsidence time function model and surface observation point subsidence speed,and then Knothe model was modified by mathematics analysis method.Modified model not only better fitting subsidence displacement series of earth subsidence observation point,but also conform to overlying stratum movement proceed during long wall working face mining from side of observation points subsidence speed,accelerate speed variation and so on,the nonlinear character of the following three stages of surface observation point subsidence could be better described,which is intial stage,rapid development stage and tardiness damping stage.Model verified need abundant observation data,in order to overcome the difficulties,underground mining of coal seam was simulated by FLAC 3D software,all 36 monitoring points for surface subsidence and subsidence speed were arranged,surface movement process during mining process was monitored,after simulation,the relationship curve between subsidence and subsidence speed and calculation step conformed to modified Knothe model curve,it illustrated that simulated mining process was feasibility,and also verified modified Knothe surface subsidence time function model could fitted dynamic process curve of surface observation points subsidence.