Field research on surface movement characteristic by coal mining under thick alluvium in Zhaogu mine area

In order to master the surface movement characteristic by coal mining under thick alluvium in Zhaogu mine area, based on the measured data of surface movement observation station on the Zhaogu No.1 mine and Zhaogu No.2 mine, the probability integral method parameters are obtained by data fitting method.Surface movement characteristic is summary analyzed, as well as the geological and mining technical reasons for the above unique laws.Based on the measured and fitted data, the angular parameters of surface movement in Zhaogu mine area are obtained.The results show that additional subsidence is caused by the water loss and consolidation of the deep aquifer after mining, resulting in a large subsidence coefficient and a small main influence angle tangent, and the larger the thickness of the loose layer in the overburden layer, the larger the subsidence coefficient, but the small main influence angle tangent value.Roof cantilever effect reduces caused by the thinner the roof bedrock of the coal seam, in addition, the soil at the stress arch axis is consolidated and compressed with the action of pressure caused by mining.The above two actions results in the decrease of inflexion offset or negative value, and the convergence of surface subsidence basin edge is too slow.Due to the large thickness of alluvium in overburden, the angular parameters of surface movement in Zhaogu No.1 mine are smaller than those in Zhaogu No.2 mine.