Research On Surface Deformation Law Of Hongliulin Coal Mine

Hongliulin Coal Mine is located In the Loess gully area of northern Shaanxi.The surface of the mining area is complex,and the gully is vertical and horizontal.Large-scale and high-strength coal mining is carried out in this area.The surface movement and deformation are more complicated,and often cause geological disasters such as landslides,collapses and collapses.It is of great significance to study the characteristics of mining surface deformation in this area.Based on the geological conditions of Hongliulin Coal Mine,this paper uses UDEC discrete element numerical simulation software to study the surface and overburden.displacement,stress variation and fracture development of S1501 working face.The thic.kness of different loess layers is studied under the condition of flat surface.The law of surface movement and deformation during coal mining under different mining heights and different soil-rock ratios;when the surface is gully,under different conditions of different overburden types,different working faces,and different working face positions,coal seam mining is carried out.The main results of the surface movement deformation law are as follows:(1)Coal seam mining is carried out under the geological conditions of S1501 working face.When the working face passes through the gully,the horizontal displacement of the slope is obviously larger than the horizontal part of the surface.The vertical d.isplacement at the foot of the slope is smaller than the displacement on both sides,and the longitudinal fracture in the loess layer is first generated.After the end of mining,the horizontal and vertical fractures in the loess layer are relatively developed.The fine-grained sandstone far away from the coal seam is equivalent to the key layer in the actual geological conditions,and plays a controlling role in the movement deformation of the overlying strata and the loess layer.(2)When the surface above the working surface is flat,the maximum settlement value and the maximum horizontal movement value of the surface change nonlinearly with the increase of the thickness of the loess layer.The loess layer has the dual function of loading and slowing the surface subsidence;the surface settlement Positively correlated with mining height,the horizontal displacement of the surface increases with the increase of mining height;as the proportion of loess layer increases,the surface subsidence increases,when the proportion of loess layer is too large(the ratio of soil to rock is greater than 2:1)The degree of surface deformation has been reduced;the sensitivity of the three factors affecting surface subsidence and horizontal displacement is analyzed by grey correlation,which are the height>soil-rock ratio>loess layer thickness.(3)Coal seam mining under one-way slope conditions,the vertical displacement at the foot of the slope is smaller than the vertical displacement on both sides,and the horizontal displacement on the slope increases first and then decreases from the top of the slope to the foot of the slope.And at the foot of the slope,the horizontal displacement is obviously reduced;the horizontal deformation has a greater influence range behind the slope than the front side of the slope,and in the case of reverse slope mining,the surface of both sides of the slope is affected by mining more than the slope There are a large number of cracks behind the slope and the slope,which will lead to instability of the slope and more likely to cause collapse under the action of rainwater scouring.(4)Coal seam mining under one-way slope conditions,when the working surface is located at different positions below the slope,the maximum surface subsidence is different,and the position is different;when the working surface is located at the lower left side of the slope,the horizontal displacement of the surface Both positive and negative values occur;when the working surface is at different positions below the slope,the horizontal displacement of the surface above the goaf is more severe,and the horizontal movement value at the bottom of the subsidence basin is not zero;the working surface is at the slope When the right side is below,its horizontal deformation has the largest influence range.(5)The coal seam mining under concave slope conditions,the vertical displacement on the slope at the slope position is greater than the vertical displacement at the slope position.From the top of the slope to the foot of the slope,the vertical displacement of the slope on both sides first increases and then decreases.Small trend;coal seam mining under convex slope conditions,the vertical displacement is the smallest near the slope;when the working surface is below the concave slope,the horizontal deformation of the surface is greater than when the working surface is in the convex slope.