Study on influence of coal mining under ancient building on deformation disturbance of overlying accumulation layer on slope

The research on the mining stability and deformation mechanism of the overlying accumulation layer on the gently inclined bedding slope, especially from the perspective of coordinating the exploitation of underground resources and the safety protection of ancient buildings on the ground is in the exploratory stage. Taking the accumulation layer of Baoyingsi slope in Shanxi Province as the research object, based on the analysis of surface dynamic monitoring and geological process mechanism, combined with numerical simulation, the stability of accumulation layer and the formation mechanism of surface cracks were studied, and the mining method was discussed and optimized. The research shows that: ① Long-wall underground mining is the cause of the deformation of the accumulation layer, and the weak characteristics of the accumulation layer and the soft and hard interbedded structure of the slope are the internal causes of its deformation. The deformation mode of the bedrock under the accumulation layer is vertical extrusion and horizontal tension, which has an amplification effect on the deformation of the accumulation layer and affects the generation of ground cracks. The deformation and failure mechanism of the accumulation layer is as follows: mining under the slope-bending of overburden rock-toppling deformation of side rock-stress concentration of underlying rock-pulling and cracking; ② The cracks in the accumulation layer are distributed near the end of the working face of the goaf in the uphill direction, and are approximately parallel on the plane, showing a zigzagging motion or serrated shape. The number of ground fissures is more than that of surface fissures, but the scale is smaller. The temple buildings are affected by the hidden tensile ground fissures, which cause the deformation of the foundation and cause the cracking of the above-ground structure. During the monitoring period after stopping mining, the deformation rate of the accumulation body tends to converge, the residual deformation is reduced, and the deformation movement is basically stable. ③ After complete mining, the accumulation layer shows tensile deformation dominated by the following dislocations, and shear strain appears. The deformation degree of the accumulation layer will be aggravated under continuous mining conditions. The maximum principal stress increment of the underlying bedrock is 1080.75 %, and the tensile stress is concentrated. ④ Short-wall room mining leaving section coal pillar is beneficial to reduce the deformation of accumulation layer.The research conclusions provide a reference for understanding the deformation and failure of the overlying accumulation layer on the slope disturbed by underground resource mining and seeking solutions for the protection of cultural relics in coal mining under ancient buildings.