基于板弯曲变形的山区煤层开采地表下沉模型

A SURFACE SUBSIDENCE MODEL OF COAL SEAM MINING IN MOUNTAIN AREA BASED ON PLATE BENDING DEFORMATION

分析了长壁工作面采煤上覆岩层破坏、移动的“三带”理论,认为地表的下沉变形受控于弯曲下沉带,且地表的最大下沉量远小于弯曲带岩层的厚度,弯曲带岩层的变形符合板的小挠度弯曲问题。在此基础上,根据山区地形地貌的特征及山体坡向与煤层倾向的关系,将地表山体简化为顺向坡、反向坡、沟槽、山岭四种情况,用薄板理论中的半逆解法分别建立了四种地貌情形下的地表下沉盆地模型。模型虽然作了一些简化假设,但体现了煤层倾角、埋深、岩层物理力学性质、地貌形状等影响开采沉陷的主要因素。

According to the theory of the“three zones”of failure and movement of the overlying strata in the longwall mining face,the subsidence deformation of the surface is controlled by the bending subsidence zone,and the maximum subsidence of the surface is far less than the thickness of the bending zone strata,therefore,the deformation of the bending zone strata conforms to the small deflection bending of a plate.On this basis,according to the characteristics of the mountain topography and the landform and the relationship between the slope direction and the coal seam tendency,the surface mountainous body is simplified into four cases:that with a forward slope,that with a reverse slope,the trench and the mountain ridge.The surface subsidence basin models in the four cases are established by a semi-inverse method of the thin plate theory.Despite some simplified assumptions in the model,the main factors affecting the mining subsidence are considered,such as the coal seam dip,the burial depth,the physical and mechanical properties of the strata,and the geomorphological shape.