老采空区地表残余沉降预计与应用

Prediction of Surface Residual Settlement Over the Old Goaf

为了对长壁垮落法开采老采空区"活化"引起的地表残余沉降进行估计,从老采空区的覆岩形态结构出发,提出把长壁垮落法开采老采空区分成2个区进行预计:边界的欠压密区和中部的压密区,给出了欠压密区和压密区的尺寸.针对边界"活化"空间的分布特征和突发性"活化"特点,提出等价成变采高的小工作面开采来预计边界"活化"引起的地表残余沉降.针对中部破碎岩体缓慢蠕变的"活化"特点,采用剩余下沉系数进行预计.分别建立了相应的预计模型,并编写了预计程序.工程实践表明,老采空区的边界蕴含着大量"活化"空间,若边界处结构失稳,将在其正上方地表产生较大的不均匀移动变形;在采宽不大的情况下,老采空区"活化"引起的最大残余沉降位置在开切眼和停采线附近上方地表,并非在采空区中部压密区.

To estimate surface residual settlement caused by ＂activation＂ of old goaf with longwall caving,we propose,for the first time,that the old goaf is divided into two areas based on the morphological structure of overlying strata.These two areas are： 1） the border brown-dense area,and 2） the central compaction zone.In addition,we have given the size of brown-dense area and the compaction zone.Aiming at the spatial distribution characteristics of border ＂activation＂ and the sudden happening of border ＂activation＂,we propose the new method that a small working face with a variable mining height is used to predict surface residual settlement caused by boder ＂activation＂.In view of the slow creep ＂activation＂ feature of central broken rock,the remaining subsidence coefficient is used for the prediction.Further more,we have established the prediction model and compiled the prediction program.Finally,we have got the conclusion that the old goaf boder area contains a large number of ＂activated＂ spaces.If the boundary structure becomes instability,surface above the goaf will have a great non-uniform deformation.When the mining width is not big,the largest residual settlement will be located near the open-off cut and near the area above the stop line,not in the central compaction zone.